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Multiframe Steel Codes - Daystar Software, Inc.

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1. ent mm Either Click on the icons for the end conditions in each direction Or gt Type in values for Kx and Ky gt Type in values for Lex and Ley gt Click OK If you choose a standard end condition the recommended Kx and Ky values will be automatically entered for you Page 30 Chapter Three ASD and AL Combined Actions ASD and AlJ When a member is subject to bi axial bending or a combination of axial tension or compression and bending it is likely to be necessary to carry out a combined check on the member s performance as a beam column This combined check usually takes the form of a comparison of the sum of the ratios of the actual stress to the allowable stress for each of the considered actions As columns are frequently subject to these types of actions there is also an option to check the side sway of a beam column The side sway check usually takes the form of a comparison of the horizontal deflection at the top of the member with a proportion of its height above ground level When checking or designing members for combined bending and compression actions under the ASD code you may wish to enter coefficients as prescribed by the code If you leave the Cm unchanged Multiframe Steel Codes will select a value for you which will be displayed in italics in the Design Details table in the Data window This value is most commonly 1 0 To set the coefficients for combined checks gt Choose Combined
2. Compression kx 1 000 ky 1 000 kz 1 000 Column Segments Restraints Major Axis Minor Axis Torsion ES xx yy Position Restraint Restraint Restraint gt Click on the icons for the end conditions in each direction or gt Type in values for K and K Page 95 Chapter Eight AISI gt Type in values for Lex and Ley gt Click OK If you choose a standard end condition the recommended K and Ky values will be automatically entered for you The initial values of L and L are the length of the member Combined Actions AISI No information is required when checking or designing members for combined actions using AISI Design Properties AISI Sometimes you may wish to set all of the design properties for a member or group of members at once This may be quicker than setting each of the design values in turn using the commands above To set all of the design variables gt Select the required members in the Frame window gt Choose Design Details from the Design menu Design Member 1 Properties Steel Grade Constraints Serviceability Stiffener s Member Bending Tension Compression m Lateral Restraints z S Members tulp laterally restrained or Pens Reduction factor flange fastened to sheeting for C a culo 1 000 Position of Lateral Restraints Lateral Restraints Segments Unbraced Length Lby fi 000 m Cbx fi 000 Lby fi 000 ri fi 000
3. Holes Diameter of Diameter of holes in the flanges of the section Flange Holes Page 44 Chapter Four AS4100 NZS3404 Total Height of Total height of any boltholes in the flanges of the Flange Holes section This value may be input directly or computed automatically when the number and diameter of flange holes are specified No of Web The number of holes in the webs of the section AM Diameter of Diameter of holes in the webs of the section KS Correction factor for the distribution of forces Total Height of Total height of any bolt holes in the webs of the Web Holes section This value may be input directly or computed automatically when the number and diameter of flange holes are specified Fabrication The method by which the section was Rolled manufactured This describes the residual stresses Member Category of member for purposes of seismic E A EE It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Code Clauses Checked AS4100 and NZS3404 When carrying out code checks Multiframe Steel Codes uses the following clauses of the applicable codes to check your structure No other checks are performed unless they are specifically listed below Checks are not carried out
4. Chapter 2 Using Multiframe Steel Codes gives step by step instructions of how to use Multiframe Steel Codes It describes all the commands and functionality provided by Multiframe Steel Codes except for the details specific to each of the design codes The following chapters provide the information particular to each design codes supported by Multiframe Steel Codes Chapter 3 ASD and AIJ describes the design checks dialogs and design properties specific to the American ASD and Japanese AIJ allowable stress steel design codes Chapter 4 AS4100 and NZS3404 the design checks capabilities and limitations dialogs and design properties specific to the Australian AS4100 and New Zealand NZS3404 limit state steel design codes Chapter 5 LRED describes the design checks capabilities and limitations dialogs and design properties specific to the American LRFD limit state steel design code Chapter 6 BS5950 describes the design checks capabilities and limitations dialogs and design properties specific to the British BS5950 limit state steel design code Chapter 7 AS NZS4600 describes the design checks capabilities and limitations dialogs and design properties specific to the AS NZS4600 steel design code Chapter 8 AISI describes how the user can specify an alternative set of design rules that can be used by Multiframe Steel Codes when designing a frame Chapter 9 AISC 2005 describes the design checks
5. K and K are the two effective length factors for the major and minor axes respectively The initial values of K and K are 1 0 Unbraced Length AS NZS4600 To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Lex corresponding to the spacing of restraints preventing compression buckling about the x x axis and L y corresponding to the spacing of restraints preventing compression buckling about the y y axis To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu Compression Compression 1 000 ky 1 000 k 1 000 Column Segments Restraints Major Axis Minor Axis Torsion ont poston Jens rien nesta gt Click on the icons for the end conditions in each direction or gt Type in values for K and K Page 83 Chapter Seven AS NZS4600 gt Type in values for Lex and Ley gt Click OK If you choose a standard end condition the recommended K and Ky values will be automatically entered for you The initial values of L and L are the length of the member Comb
6. Unbraced Lengths and Effective Length Factors BS5950 To determine the buckling load for a member the user may choose to specify a single unbraced length of the member for buckling about each principle axis It is also necessary to enter an effective length factor to indicate the type of restraint applied to the ends of the unbraced span of the column These may be different for buckling in the major and minor axis directions The effective lengths for determining the buckling capacity of the member are given by Lx Kx Lcx and Ly Ky Ley where Lcx and Lcy are the unbraced lengths of the member and Kx and Ky are the two effective length factors for the major and minor axes respectively The initial values of Lex and Lcy are the length of the member and the initial values of Kx and Ky are 1 0 Column Segments BS5950 A more sophisticated method for the design of a member for compression allows for the division of the member into a number of column segments These segments are defined by restraints that resist column buckling that are applied at intervals along the member In Multiframe Steel Codes restraints against buckling can be specified at joints along a design member These restraints are used to break the member into a number of column segments that may differ for the design of the member about its major and minor axis The effective length associated with each segment may also be specified to account for the restraint conditions at each
7. from the Design menu Combined Xx Combined Cm Cmy f 000 Cancel Help gt Enter the values for Cmx and Cmy gt Click OK Default Design Properties ASD and AlJ There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Default Yield strength of the section s steel Ultimate Tensile Strength of the section s steel strong axis weak axis the section s strong axis length the section s weak axis length LJ A stiffeners along the web of a beam stiffeners Page 31 Chapter Three ASD and AL Flange Hole Area of any bolt holes in the flanges of the section Area This area will be deducted from the cross sectional area when computing tensile stress Web Hole Area of any bolt holes in the web of the section This Area area will be deducted from the cross sectional area when computing tensile stress Area Reduction factor This factor is applied to the 1 0 sectional area after bolt holes have been deducted when calculated tensile stress You can use it to reduce the effective area by a defined amount It must have a value between 0 and 1 0 Page 32 allowable compressive stresses in bending See ASD code for details section s strong axis see ASD code section s weak axis see ASD code The method by which the section was manufactured This describes the residual stresses in the section Code Clauses C
8. 31 751 196 851 11 97 0 585 5 214 ksi Minor Axis Fb 0 75 Fy 0 75 36 27 ksi sl This report can be edited via Cut Copy Paste and Clear printed or saved to and recalled from a disk file You can type directly into the report or edit the text in the report however modifying the properties of the fonts in equations can easily corrupt the formatting of the design equations as the Greek characters and mathematical symbols are displayed using the Symbol font Design Members A design member is a single member or a series of connected members that can be considered as a single member for design purposes By default each member in the frame is a design member Members to be grouped together into a Design Member must satisfy the following conditions Page 7 Chapter One Introduction e All members must have the same section type e All members must have the same orientation e All members must be rigidly connected internally ends may be released e All members must be approximately co linear e All members must be connected with the local x axis facing the same direction e Members may have rigid offsets at internal joints but the flexible portions of the members must be continuous within the design group e There must not be any restraints on the internal connecting nodes Viewing Results Using Design Members The action and displacement diagrams for a design member may be viewed in the Plot Window Double clicking on a desi
9. Chapter 2 Using Multiframe Steel Codes AAA 11 Design Procedure cintas atan Sie TET 11 Working with Design Membere 12 Setting Design Properties cicatrices 12 Setting Design Properties cicatrices 13 Setting Section TYPE isc aria D s 15 setting Steel Grade icon dol li 15 Setting Design Constramts nono nono nono no iE E EE ER E crac 18 Setting Section Constraints secsec toe iy apenes eee s asne EEE Ensa EREE 18 Setting Frame Py pees tica s 19 Setting Allowable Stresses nono nonnnncnncnnn cnn cana nrnn cano 19 Setting Acceptance Rat iniciacion did ladies 20 Setting Capacity Factor Susini 20 Checking Frame is naninaai apilar acia nnn 20 Displaying Efficiency sicions en ena E eE E ESE 22 Goverming Load Cases inciociionsici naolinoncecanadondgontq sE save ENEE Eet 22 Designi g a E 23 Optimum Sections EE 24 Tips On Optimisation srdecne cesia conan ono conan cnn nono n crono nn nc nn S 25 Finding Design Valdes coito EEN decada oran 25 O O O 25 Printing the Report Wrmdow nono nono nonn nono nono nccnnccnne ns 26 SAVING VOUT WO loucotitia sso yieeetyode es elecs teenie ti edeeaeeccee 26 Saving the GE 26 Chapter 3ASDiand AM EE 27 Design Checks ASD and AU 27 Bending ASD and AV ii ce esses sheets einen aoe ale elle 27 Design Constraints AU 27 Unbraced Length ASD and AU 27 Bending Coefficient AS 28 Web Stiffener Spacing ASD and AIJ oo eeeeseeeneecreecnseceaecnaeenseens 28 Bending Dialog ASD and Al oo eeee
10. Combined Checks When a member is subject to combined actions generally bi axial bending or a combination of axial tension or compression and bending it is likely to be necessary to carry out a combined check on the member s performance Serviceability Checks Serviceability checks allow the user to specify the maximum deflection of a member For some codes the serviceability checks have been included with the Bending checks Seismic Checks When a structure is located in a seismic region some additional design requirements are imposed by some design codes This typically requires that certain members within a steel frame be designed for ductility Checking a member Multiframe Steel Codes can be used to check the compliance of a member to a steel design code When checking a member Multiframe Steel Codes computes an efficiency for each of the active design checks The efficiency is a measure of the member s design action design stress or deflection expressed as a percentage of the allowable capacity as calculated using the design rules That is an ideal member is loaded or stressed to 100 of its allowable design capacity or slightly less and a member labelled as being 50 efficient is twice as strong as it needs to be When checking a member the user has the option to output the design calculations performed by Multiframe Steel Codes to the report window Designing a member As well as helping to check a frame s compliance with
11. Position Restraint Restraint Restraint Lim 0 000 Y y M 2 1 3847 Y iv gt Enter the restraints associated with each node The restraint information is used to build a list of column segments that span between the specified restraints gt Click on the Major Axis tab This displays a table of column segments that will be used for the design of the member for compression when considering buckling about the major axis Restraints Major Axis Minor Axis Torsion 1 000 gt Enter the effective length factor K for each segment gt Click on the Minor Axis tab and enter the effective length factors for the minor axis column segments gt Click on the Torsion tab and enter the effective length factors for the calculation of torsional buckling resistance gt Click OK Page 109 Chapter Five LRFD Combined Actions AISC 2005 2010 The design of a member for combined actions is divided into three design checks The user can select to check the member for torsion or biaxial bending in conjunction with either a tensile or compressive axial force The user is not required to provide any additional design properties for the combined actions checks as it uses results already derived from the tension compression and bending checks Serviceability AISC 2005 2010 Multiframe Steel Codes provides two design checks for the serviceability of a member These design checks are used to check that the def
12. fby 0 6 Fy lt 1 0 Cancel M Side Sway lt fi in M Side Sway lt BEN in Only the calculations that have their check box checked will be used when you use the Check or Design commands Page 129 Chapter Ten Steel Designer Reference Chapter 12 Multiframe Steel Codes Reference This chapter summarises the extended functionality of windows and the extra menu commands that are available in Multiframe when Multiframe Steel Codes is enabled e Windows e Menus Windows Multiframe Steel Codes operates within the standard Multiframe windows and adds a Report window The following windows are available e Frame Window e Data Window e Load Window e Result Window e Plot Window e Report Window Frame Window This window is used for specifying the sections and design properties of the members in a frame Data Window This window is used for viewing the data describing the geometry and loading of the frame and for displaying and editing the design properties of the structure Load Window This window is used for viewing the loading applied to the frame One load case at a time may be viewed in this window You can choose which load case is displayed by choosing the appropriate item from the bottom of the Case menu Result Window This window is used for viewing the results of the analysis and design calculations carried out on the frame The results for one load case at a time may be viewed in this window You can ch
13. gt Click each tab and enter the design values gt Click OK Page 96 Chapter Eight AISI As a shortcut you can examine and change the design details for a single member by double clicking on it in the Frame window Steel Grade AISI To determine the allowable stresses for a member it is necessary to know the grade of steel to be used for the section This grade determines the yield strength Fy and ultimate tensile strength F of the material of the section To set the Steel Grade gt Select the required members in the Frame window gt Choose Steel Grade from the Design menu Steel Grade Steel Grade m Grade Standard z Steel Grade Grade 36 z Strength ksi Fu ksi Fabrication Cold Formed y In this dialog you can either gt Choose a standard and steel grade from the drop down menu or gt Type in values for F and F Finally gt Choose the method of fabrication to indicate the state of residual stress in the section gt Click OK If you choose a standard grade of steel the F and F values will be automatically entered for you The initial value for the steel grade for all members is A36 grade 36 Page 97 Chapter Eight AISI Page 98 Code Checks AISI When carrying out code checks to AISI Multiframe Steel Codes uses the following clauses of to check your structure No other checks are performed unless they are specifically listed belo
14. 54 Compression ERRD ai sa a 54 Compression Dialog LPRID nono ncon nono nccnnccone ns 55 Combined Actions LER D vuitton pia ete 56 Serviceability s ERD ui asa 56 Serviceability Dialog LPRID AAA 56 Default Design Properties LPRIN AAA 57 Code Clauses Checked LERD soon 58 LRFD Clauses Cheese Sen are ee EE ee 58 LRFD SAM Clauses Checked AA 59 Chapter aleeden EE iia ia 61 Notations BS5950 cuate 61 Design Checks BS5950 ee ue e ee e sient E 61 Bending BS3950 ue EE ates taa 62 Lateral and Torsional Restraints Baan 63 Unbraced Length Ly and Bending Coefficient mur BS5950 63 Web Stiffener Spacing Baan 64 Load Herght BS iii ina 64 Bending Dialog Ban 64 Generate Lateral Restraints Dialog Ban 65 Tensi n BIO Oia EE oe Ree ntti ean 66 Bolt Holes BSS950 cas cetieenieces led E cee wine E eae ae 66 Area Reduction Coefficient BS5950 ooo eee eeceeseeeneeeneeersecesecesecnseenseens 67 Tension Dialog Bann 67 Compression BS ica a i ds 68 Unbraced Lengths and Effective Length Factors Ban 69 Column Segments BS5950 eee eeceseeseeeeeeeeeeeseeeaeecaeecsaecsaesaecnaeenseen 69 Compression Dialog Baan 69 Combined Actions Baan 71 Serviceability BS5950 k esens nee a E T E E E E i 72 Serviceability Dialog BS5950 oo eee ceeceeeceeeeeeeeeeseeeseeeneecaecnaesnaeenseees 72 Default Design Properties BS5950 00 ee eesceseceseceseceseceseeeseeeseeseneseaee
15. 74 BS5950 British Standard BS5950 1 2000 Structural use of steelwork in buildings Part 1 British Standards Institution May 15 2000 Clauses used 3 4 3 5 3 6 4 2 4 3 4 4 4 6 4 7 and 4 8 Reference is also made to Annex s B 2 Cl C 2 I 2 and 1 3 The design checking procedure is as follows Any section properties missing from the sections library that are required for the design of the section are computed The section is classified as plastic compact non compact or slender using clause 3 5 2 Any section shape not supported by Multiframe Steel Codes shall be classified as compact For sections classified as class 3 semi compact the effective plastic moduli are computed using clause 3 5 6 For sections classified as class 4 slender the effective area and effective elastic moduli are computed using clause 3 6 Only the design of symmetric I sections with slender flanges rectangular hollow sections equal angles and circular hollow sections are supported by this design module For major and minor shear checks the design shear force is checked to be less than the shear capacity found from clause 4 2 3 No allowance is made for the effect of boltholes when computing the shear capacity of the member For major and minor axis bending checks the design bending moment is checked to be less than the moment capacity as found using clause 4 2 5 Note that the moment capacity is conservatively computed on the basis
16. Check V Bending IV Major Bending H Major Shear LL incl 4 5KN load at ridge b Major Deflection MV Minor Bending IV Minor Shear Y Minor Deflection MV Tension H Compression IV Slendemess lV Compression V Combined M Tension and Bending V Compression and Bending MV Sidesway Report E None Brief C Full Cancel ASD AlJ 20 Chapter Two Using Steel Designer Check x Check Strength Limit States IV Bending MV Major Section V Minor Section IV Major Member IV Major Shear IV Minor Shear MV Tension V Compression M Section IV Major Member IV Minor Member Y Combined IV Major Section IV Minor Section IV Major In plane Member V Minor In plane Member M Dut of Plane Member IV Biaxial Section IV Biaxial Member Serviceability Limit States H Serviceability Self Weight LL incl 4 5kN load at ridge IV Primary check V Secondary check Dead Load Pe LL incl 4 5kN load at ridge M Seismic 1 25DL 1 5DL General Axial Limit IV Axial Compression Major Axis IV Axial Compression Minor Axis IV Gravity Load Limit o C None C Brief C Full Ex E o Cancel AS4100 NZS3404 gt Check the boxes of the design rules to be checked gt Shift or Ctrl Click on the load case names in the list to include or remove them from the check gt If you want a summary report in the Report window check the Brief Detailed or Full report radio buttons gt Click OK Multiframe Steel Code
17. Serviceability Eurocode 3 isis iii risas 123 Serviceability Dialog Eurocode 3 123 National Anne Xs accidents ee ines hue EE nt eg 123 National Annex Dialog Eurocode 3 123 Default Design Properties Eurocode 3 124 Code Clauses Checked Eurocode 2 125 Ehapter 11 User Codes irc iia selects stos Eege 127 User Codes Concepts iia ii 127 User Code Procedur s Cut ee laredo srt EE 127 Chapter 12 Multiframe Steel Codes Reterence conc crac cono nonnnos 131 A edee EE tee Beie eegenen 131 Frame Wind West 131 Data WINdO Wir iria 131 Edad WNdOW escindida pe Se he 131 Result Window neate rod eae 131 Plot Wind Wi ds 131 Kette eet Ee ee 132 MENUS ii aia do ae ee ie EE dE 132 Group Men s eebe eege id lada dira cod Rees 132 Deeg Medi iS 132 Code Submeti ata irte 134 Display Menine EE E 135 Efficiency Sube Uca arista 135 Help Men ds 138 Referencese ca ice lonas eee ated ae Sle has eher de 140 Index ee eet EE ia tons 141 About This Manual About this manual This manual is about Multiframe Steel Codes a structural steel design application for the Windows operating system Multiframe Steel Codes is an add on module to the Multiframe structural analysis software Chapter 1 provides an overview of Multiframe Steel Codes and it s capabilities Once you are familiar with the basic concepts and knowledge required to use Multiframe Steel Codes you may refer to the detailed instructions in Chapter two
18. The top flange was the critical flange and e The bottom flange was the critical flange In Eurocode 3 no distinction is made between different types of lateral restraints However to be compatible with other design codes Multiframe Steel Codes allows for lateral restraints at a cross section to be classified as follows e Full Restraint supports the cross section against lateral displacement of the critical flange and prevents twist of the cross section e Partial Restraint provides support against lateral displacement of the section ata point other than the critical flange and prevents twist of the cross section e Lateral Restraint resists lateral displacement of the critical flange only For the purpose of design in Eurocode 3 each of these restraint types is consider adequate to provide lateral support to the cross section at which they are applied Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained in which case the member would be regarded as a cantilever The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange Chapter Nine User Code The location and type of lateral restraints can be displayed in the Frame and Plot windows The display of lateral restraints can be turned on or off
19. Type in the stiffener spacing s Tension ASD and AlJ The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the cross section of the member and an area reduction coefficient used to compute the effective area of the section Chapter Three ASD and AL Bolt Holes ASD and AlJ When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other reductions If the members contain significant areas of boltholes which need to be taken into account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes The initial value for the area of boltholes is zero The net area of the section is the gross area minus the combined area of boltholes in the flange and web Area Reduction ASD and AlJ The net area is multiplied by the area reduction coefficient U to give the effective net area of the section The default value of U is 1 0 1 e no reduction in area Tension Dialog ASD and AlJ To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Tension Bolt holes in flange 0 000 in 2 Bolt holes in web 0 000 De Area reduction c
20. bending member checks the design bending moment about the major principle axis is checked to be less than the nominal member moment design capacity as found using clause 3 3 3 For some section shapes the bending of distortional buckling check may not be included clause 3 3 3 3 For major and minor shear checks the design shear force is checked to be less than the nominal shear capacity found from section 3 3 4 For tension checks the design axial tension force is checked to be less than the nominal section design capacity in tension as computed using clause 3 2 For compression section checks the design axial compressive force is checked to be less than the nominal section design capacity in compression as computed using clause 3 4 1 For major and minor compression member checks the design axial compressive force is checked to be less than the nominal member design capacity in compression as computed using clause 3 4 2 3 4 5 For all combined action section checks the design axial force N is the maximum axial force in the member and the design bending moments Mx and My are the maximum bending moments in the member For major and minor combined section checks the design bending moment is checked to be less than the nominal section moment design capacity reduced by axial force compression or tension as computed using clause 3 5 1 References AS NZS4600 You may find the following books useful to refer to if you need in
21. capabilities and limitations dialogs and design properties specific to the AISC 2005 LRFD and ASD steel design codes Chapter 10 Eurocode 3 describes the design checks capabilities and limitations dialogs and design properties specific to the Eurocode 3 steel design code Chapter 11 User Code explains how to enter custom design rules Page 1 About this manual Chapter 12 Multiframe Steel Codes Reference describes gives an overview of the windows and menus of Multiframe Steel Codes and a summary of the commands used Chapter One Introduction Chapter 1 Getting Started This chapter provides an introduction to Multiframe Steel Codes It outlines the basic concepts and knowledge needed to use the program as well as the additional functionality it introduces to the Multiframe user interface in the following sections e About Multiframe Steel Codes e Design Codes e Installing Multiframe Steel Codes e Design Overview e Windows e Design Members e Coordinate Systems e Properties for Design e Shear Area About Multiframe Steel Codes Multiframe Steel Codes is an add in module for Multiframe that is used for checking or designing a steel frame in accordance with various codes of practice After analysing a frame in Multiframe you can use Multiframe Steel Codes to check the members in the structure for compliance with a design code You can also use Multiframe Steel Codes to choose the lightest weight sections w
22. clauses will not be enacted In cases where a material does not match to a standard steel grade it is recommended that the steel grade be assigned directly as described below Alternatively to set the Steel Grade directly and override the properties of the material gt Select the required members in the Frame window gt Choose Steel Grade from the Design menu 16 Chapter Two Using Steel Designer Steel Grade E Steel Grade m Grade Standard Jas 3679 y Steel Grade 250 Strength Fy 250 000 MPa Fu 410 000 MPa Fabrication Hot Rolled Either AS4100 shown gt Choose a standard and or steel grade from the pop up menu or gt Type in values for Fy and Fu or Fy lt 40mm and Fy gt 40mm when using AIJ gt Choose the fabrication type for the section gt Click OK If you choose a standard and or a grade of steel the Fy and Fu values will be automatically entered for you If no material has been assigned to a member then the initial value for the steel grade for all members is Code ASD amp LRFD AS4100 NZS3404 BS5950 User US User Australia User New Zealand Code AU User Japan Grade A36 AS3679 grade 250 AS3679 grade 250 S235 Grade SS400 Fy 36ksi 250MPa 250MPa 235MPa 36ksi 250MPa 250MPa Fy lt 40mm 2 4t cm2 2 4t cm2 Fu 58ksi 410MPa 410MPa 340MPa 58ksi 410MPa 410MPa Fy gt 40mm 2 2t cm2 2
23. consider axial force and bending about a single axis only The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Page 61 Chapter Six BS5950 r Design Checks IV Bending IV Major Section IV Major Member IV Major Shear IV Tension IV Compression IV Section IV Major Member IV Combined IV Biaxial Tension IV Biaxial Compression Y Minor Section IV Minor Shear IV Minor Member Section IV Biaxial Compression In plane IV Biaxial Compression Dutof plane IV Serviceability IV Primary IV Secondary IV Auxillary Combined I Tension Mx IV Mx Comp Section IV Mx Comp In plane Biaxial Section IV Biaxial In plane IV Tension My JM My Comp Section JM My Comp In plane IV My Comp Dut of plane Y My Comp Dut of plane IV Biaxial Out of plane r Reporting 2 None Brief C Detailed Full Strength Limit States Int Suction under CW ISCW Int Suction under DA ISL 1 25DL 1 5LL D 8DL CW HPCW 1 25DL CW ISCW O 8DL L W1 IPLW 1 25DL LW2 ISLW l P D LL incl 4 5KN load at ridge Cross Wind Cw Bending BS5950 The design of a member for bending consists of five design checks These check the section capacity of the member about the major and minor axes the shear capacity about both axes and the member and the buckling capacity about the major axis W
24. determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by Lx Kx L and Ly Ky L Where L is the length of the member and Kx and Ky are the two effective length factors for the major and minor axes respectively The initial values of Kx and Ky are 1 0 Unbraced Length AS4100 and NZS3404 To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Lcx corresponding to the spacing of restraints preventing compression buckling about the x x axis and Lcy corresponding to the spacing of restraints preventing compression buckling about the y y axis The initial values of Lex and Ley are the length of the member Compression Dialog AS4100 and NZS3404 To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design me
25. ends of the segment When column segments are specified the design of the member will be performed by considering the design of each segment separately Compression Dialog BS5950 To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu If the unbraced lengths of the member are to be specified directly then gt Select the Unbrace Length radio button Page 69 Chapter Six BS5950 Page 70 Compression gt Type in values for Kx and Ky gt Type in values for Lex and Ley gt Click OK Otherwise if the design for compression is to be performed using column segments gt Select the Column Segments radio button The tabbed control in the dialog will become active The first page in this table lists the location of joints along the members and indicates if they provide restraint against column bucking about either axis of the member Chapter Six BS5950 x Compression C Unbraced Lengths kaf fi 0 Loy jE m ky be cy jE m Ze Column Segments Restraints Major Axis Minor Axis gt Enter the restraints associated with each node The restraint information is used to build a list of column segments that span between the specified restraints gt Click on the Major Axis tab This displays a table of column segments that will be used for the design of the member for compression when consideri
26. for the current load case in the Plot window Combined Out of plane Display the Combined Out of plane efficiency as a colour on each member for the current load case in the Plot window Combined Biaxial Section Display the Combined Biaxial Section efficiency as a colour on each member for the current load case in the Plot window Combined Biaxial Member Display the Combined Biaxial Member efficiency as a colour on each member for the current load case in the Plot window Primary Deflection Display the Primary Deflection efficiency as a colour on each member for the current load case in the Plot window Secondary Deflection Display the Secondary Deflection efficiency as a colour on each member for the current load case in the Plot window ASD AL The following items are available in the Efficiency submenu when using USA and Japan versions of Multiframe Steel Codes Overall Display the Overall efficiency as a colour on each member for the current load case in the Plot window Major Bending Display the Major Bending Major Section Bending efficiency as a colour on each member for the current load case in the Plot window Minor Shear Display the Minor Shear Bending Minor Shear efficiency as a colour on each member for the current load case in the Plot window Page 137 Chapter Ten Steel Designer Reference Page 138 Major Deflection Display the Major Deflection efficiency as a colour on
27. for the frame This is only used with limit state design codes Use Best Sections Automatically replace the section type of each member with its lightest weight section as chosen using the design command Code Submenu The code menu allows you to select the design code you wish to use for checking The current code is indicated with a check mark beside the item This determines which code 1s used when you do design calculations AS1250 Not currently implemented AS 4100 Australian steel design code AS 4600 Australian New Zealand steel design code NZS 3404 New Zealand steel design code BS5 950 British steel design code CISC Not currently implemented Eurocode Eurocode 3 steel design code AlJ Current Japanese steel design code ASD American ASD steel design code Chapter Ten Steel Designer Reference LRFD American LRFD steel design code User Allows the user to set their own design criteria and checks Edit User Code This command lets you edit the design calculations that will be used when you choose to check or design a frame using the User code You can choose which checks should be performed and what calculations should be used for each check You can type in your own equations Display Menu The Display menu lets you control what s displayed in each of the windows Data Design Details Display a table in the Data window of the design information for each of the members in the fram
28. gt Click OK As a short cut you can examine and change the design details for a single member by double clicking on it in the Frame window Member 22 Properties NZS3404 shown 14 Chapter Two Using Steel Designer Setting Section Type If necessary you can change the section type of a member manually in Multiframe Steel Codes Note however that if you do so you will need to re analyse the structure using the Analyse command from the Case menu To set the section type for a member or group of members gt Select the required members in the Frame window gt Choose Section Type from the Frame menu Select Section xl Group Section United States sections library shown gt Choose the section from the list gt Click OK Setting Steel Grade To determine the allowable stresses or design capacities for a member it is necessary to know the grade of steel to be used for the section This grade determines the yield strength Fy and ultimate tensile strength Fu of the material of the section The strength of the steel may be specified by assigning a material choosing a standard steel grade supported by the current design code or by specifying the values of the Fy and Fu directly The Japanese AU code does not require the ultimate tensile strength Fu but instead requires the user to specify the yield strength Fy for steel thicknesses of less than and greater than 40mm To set the material for a member o
29. gt Click on the icons for the end conditions in each direction or gt Type in values for Kx and Ky gt Type in values for Lex and Ley gt Type in values for Kz and Lez gt Click OK If you choose a standard end condition the recommended Kx and Ky values will be automatically entered for you Combined Actions LFRD The design of a member for combined actions is divided into three design checks The user can select to check the member for biaxial bending or biaxial bending in conjunction with either a tensile or compressive axial force The user is not required to provide any additional design properties for the combined actions checks as it uses results already derived from the tension compression and bending checks Serviceability LFRD Multiframe Steel Codes provides two design checks for the serviceability of a member These design checks are used to check that the deflection of a member about either the major or minor axes does not exceed a specified deflection limit Serviceability Dialog LFRD To set the design properties of a member for serviceability gt Select the required members in the Frame window gt Choose Serviceability from the Design menu Serviceability x Serviceability L250 mm Minor axis deflection Secondary Deflection Check e Major axis deflection pe zen CH Minor axis deflection Chapter Five LRFD code gt For each deflection chec
30. is at the shear centre If there are no transverse stiffeners leave the stiffener spacing set to zero Tension AISI When checking or designing a member for tension you need to specify the correction factor for the distribution of forces at the ends of the member If the members contain significant areas of bolt holes which need to be taken into account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Tension Holes No Diameter 0 000 Mmm Total Height 0 000 Mmm Correction Factor Kt 1 0 gt Type in the number and diameter of holes in the webs and flanges and the total height of holes will be computed automatically or gt Type the total height of holes in the webs and flanges directly gt Choose a value for the correction factor kt if required gt Click OK The total height of holes in the webs or flanges is used to compute the cross sectional area of holes in the section This is used compute the net area of the section and also for computing the effective section modulus The initial value for the number and diameter of bolt holes is zero When checking or designing members for compression it is necessary to specify the effective length and unbraced length of the m
31. is made between different types of lateral restraints However to be compatible with other design codes Multiframe Steel Codes allows for lateral restraints at a cross section to be classified as follows Chapter Five LRFD code e Full Restraint supports the cross section against lateral displacement of the critical flange and prevents twist of the cross section e Partial Restraint provides support against lateral displacement of the section at a point other than the critical flange and prevents twist of the cross section e Lateral Restraint resists lateral displacement of the critical flange only For the purpose of design in AISC 2005 2010 each of these restraint types is consider adequate to provide lateral support to the cross section at which they are applied Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained in which case the member would be regarded as a cantilever The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange The location and type of lateral restraints can be displayed in the Frame and Plot windows The display of lateral restraints can be turned on or off via the Symbols Dialog which contains options for displaying and labelling lateral restraints The restraints are d
32. m Constraints TP Material Requirements Section Requirements Major axis PF Section Requirements Minor axis IT Beam m Column I Part of Seismic resisting system Clause 12 8 3 1 b gt Choose the member category from popup menu gt Select each of the design constraints to be tested gt Identify if the member is part of the seismic resisting system gt Click OK Default Design Properties AS4100 and NZS3404 There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Default Yield strength of the section s steel 250Mpa Ultimate Tensile Strength of the section s steel 410Mpa Kx Effective length factor for buckling about the 1 0 section s strong axis Ky Effective length factor for buckling about the 1 0 section s weak axis Lex Unbraced length for bracing preventing buckling Member s about the section s strong axis length Ley Unbraced length for bracing preventing buckling Member s about the section s weak axis length Lateral The lateral restraints acting on the member Each end of restraints the member is fully restrained at both flanges Load Height The position of the loading on beam shear centre Shear Centre or top flange s Spacing of web stiffeners This is the spacing of 0 0 i e no any stiffeners along the web of a beam stiffeners No of Flange The number of holes in the flanges of the section
33. moments Mx and My are the maximum bending moments in the member For the combined axial tension and bending check the design bending and axial force are checked to determine if they satisfy clause 4 8 2 For the combined axial compression and bending checks the design bending and axial force are checked to determine if they satisfy clause 4 8 3 The auxiliary combined action checks consider a combination of two actions and take the value of the action not considered as zero For combined biaxial checks the design bending moments are checked to satisfy clause 4 9 For the combined axial tension and major bending check the design bending and axial force are checked to determine if they satisfy clause 4 8 2 taking the value of My as Zero Similarly the combined axial tension and minor bending check the design bending and axial force are checked to determine if they satisfy clause 4 8 2 taking the value of Mx as zero For the combined axial compression and major bending checks the design bending and axial force are checked to determine if they satisfy clause 4 8 3 taking the value of My as zero For the combined axial compression and minor bending checks the design bending and axial force are checked to determine if they satisfy clause 4 8 3 taking the value of Mx as Zero Page 75 Chapter Seven AS NZS4600 Chapter 7 AS NZS4600 This release note explains the AS NZS4600 design code in Multiframe Steel Codes It provi
34. on hybrid members composite members or tapered members Checks on mono symmetric I sections are not considered as are checks using actions computed using plastic analysis The alternative design provisions provided by the code for combined actions checks are automatically used if the member meets the required criteria AS4100 Clauses Checked Australian Standard AS4100 1990 Steel Structures Standards Australia October 26 1990 including Amendment No 1 August 3 1992 Amendment No 2 June 14 1993 and Amendment No 3 December 5 1995 Clauses used are 4 4 4 6 5 1 5 2 5 3 5 6 5 11 6 1 6 2 6 3 7 1 7 2 7 3 8 3 and 8 4 The design checking procedure is as follows For first order analyses the design bending moments are amplified using the factors determined using clause 4 4 2 and 4 6 2 Amplification factors for sway frames are not considered and a second order analysis should be used for sway frames requiring moment amplification The section is classified as compact non compact or slender about its major and minor axes using clause 5 2 The effective area and form factors are determined using clause 6 2 Page 45 Chapter Four AS4100 NZS3404 Page 46 For major and minor bending section checks the design bending moment is checked to be less than the nominal section moment design capacity as found using clause 5 2 For bending member checks the design bending moment about the major principle axis 1s checked to b
35. ratio is computed as the maximum of KxL rx and KyL ry This is checked to be less than the allowable slenderness ratio of 200 for compressive members or 300 for tensile members in accordance with clause El Chapter Three ASD and AL For compression checks the compressive stress is checked to be less than the allowable Fa as computed in section E2 For combined compression and bending checks the stresses are checked to be low enough to satisfy equations H1 1 to H1 3 For combined tension and bending checks the stresses are checked to be low enough to satisfy equation H2 1 For sway checks the horizontal deflection of the highest part of the member is checked to be less than Y 300 where Y is the height of the highest part of the member above the plane y 0 Checks are not carried out on hybrid members composite members or tapered members AlJ Clauses Checked Design Standard for Steel Structures Architectural Institute of Japan March 1979 Clauses used are 5 1 5 6 6 1 6 2 8 1 10 1 11 1 11 2 11 3 The design checking procedure is as follows Allowable stresses are determined from table 5 1 and according to equations 5 1 5 2 5 3 5 4 5 5 5 6 5 7 and 5 8 as appropriate For major and minor bending checks the width thickness ratio of the section s elements are checked in accordance with equations 8 1 8 2 8 3 8 5 and 8 6 as appropriate The bending stress is checked to be less than the allowable fb as found in secti
36. seismic member checks the design axial force is checked to satisfy clauses 12 8 3 1 a b and c Note that clause 12 8 3 1 c is checked using N N Chapter Five LRFD code Chapter 5 LRFD This chapter describes the implementation ofthe AISC Load and Resistance Factor Design Specification for Structural Steel Buildings LRFD and Load and Resistance Factor Design Specification for Single Angle Members LRFD SAM steel design codes within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by the code e Notation e Design Checks e Bending e Tension e Tension Dialog e Compression e Combined Actions e Serviceability e Default Design Properties e Code Clauses Checked Notation LFRD The notation used in Multiframe Steel Codes generally follows that used in the LRFD and LRFD SAM Use has been made of subscripts to clarify the axis of the member to which a quantity refers For example the nominal flexural strengths about the X and Y axes are denoted M and My respectively The geometric axes of a member are denoted as the X and Y axes where X represented the horizontal axis of the member and Y the vertical axis of the member For design to LRED it is assumed that the X axis is the major axis and Y is the minor axis For most sections these corresponds to the principal axes but for some sections such as angles the geometric axes do not correspond t
37. set the National Annex properties for a model gt Choose National Annex from the Design menu must have Eurocode 3 selected Page 123 Chapter Nine User Code National Annex Select National Annex Partial Safety Factors gamma Mo 1 000 gammaM1 1 000 gammam2 1 100 Lateral Torsional Buckling a Rolled Sections i ud Hoby Sections b For Welded Sections lambdaLT O 0 400 0 200 beta 0 750 1 000 Slenderness Limit Class 1 amp 2 Class 3 amp 4 Sections Sections lambda c0 oam 0 400 Interaction Factors kyy kyz kzy and kzz determined using Annex A Method 1 for doubly symmetric sections only Annex A Method 1 for all sections Annex B Method 2 for all sections gt From the Select National Annex drop down box choose the country you are working in All other fields will be automatically populated If your country is not available choose Other gt If you have chosen Other or want to change any of the properties type in the desired values gt Click OK to save and use these selections Default Design Properties Eurocode 3 There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Default Yield strength of the section s steel 250Mpa Ultimate Tensile Strength of the section s steel 410Mpa ky Effective length factor for buckling about the 1 0 section s strong axis section s weak axis Unbraced le
38. spans in determining the capacity of the member Alternatively the laterally unbraced length Ly can be specified You may need to specify a number of properties relating to the location and type of lateral restraints and the stiffener spacing along the member Lateral Restraints AISC 2005 2010 If the spacing of lateral restraints along the member is specified Multiframe Steel Codes uses this information to break the member up into a number of spans in order to determine lateral torsion buckling capacity of each span In Multiframe Steel Codes these spans are known as segments Each lateral restraint specified by the user is assumed to provide bracing against lateral displacement of the critical flange and or prevent twist of the cross section At any cross section the critical flange is the flange that in the absence of any restraint at that cross section would deflect the furthest during buckling of the member In most members the critical flange will be the compression flange However for a cantilevered member the critical flange is the tension flange For each restraint located along a member the user must specify the type of restraint As this depends upon which flange is the critical flange which is not know a priori the user must specify the type of lateral restraint that would be present at a section if e The top flange was the critical flange and e The bottom flange was the critical flange In AISC 2005 no distinction
39. subtracting the area of holes in the section The effective area is then calculated as the net area A times the area reduction coefficient U If the member is been checked for tension of compression the slenderness of the section is checked to ensure that it meets the limits set out in Section B7 For angle members the slenderness about either of the geometric axes is determined using the minimum radius of gyration of the section If the member is a plate web girder the section is checked to determine is if meets the web slenderness limits specified in Appendix G1 For each serviceability load case The maximum local displacement of the member is compared to the deflection limits specified deflection limits For each load case representing a strength limit state The design actions or required strengths of the member are determined as the maximum moment shears and axial forces within the member For first order analyses the design bending moments are amplified using the factors determined using clause C2 Only moment amplification of braced frames is considered which corresponds to the situation in which no moments result from the lateral translation of the frame As such moment amplification is computed using only the first term of the right hand side of equation C1 1 Amplification factors for sway frames are not considered and a second order analysis should be used for sway frames requiring moment amplification Chapte
40. the design rules Multiframe Steel Codes can also help you to select the lightest weight section that satisfies the design rules In this case Multiframe Steel Codes iterates through the current group of sections until it finds the optimal section that satisfies the selected design checks Multiframe Steel Codes also computes the efficiency of the optimal section for each of the active design checks Reporting Multiframe Steel Codes can produce a detailed report of the design calculations it performs for each member The level of reporting can be tailored by the user to reduce the amount of detail shown in the report The design calculations produced by Multiframe Steel Codes are displayed in the Report Window You can copy and paste from this window into other programs save from it in RTF format or directly print the contents of the window Page 5 Chapter One Introduction Alternatively you can choose to output the design calculations directly to Microsoft Word This option can be specified in the Preferences Dialog If this option is selected and Microsoft Word is installed on the computer Multiframe will automatically run Word when it is required for reporting The design report will be placed into a new document in Word This method of reporting is very fast and gives you direct access to the advanced printing and formatting options of Microsoft Word Windows When Multiframe Steel Codes is activated within Multiframe the content
41. the thickness of the section to determine the total reduction in area of the section The initial value for the area of boltholes is zero Correction Factor AS4100 and NZS3404 When checking or designing a member for tension using AS4100 or NZS3404 you need to specify the correction factor for the distribution of forces at the ends of the member The correction factor ke has a default value of 1 0 Tension Dialog AS4100 and NZS3404 To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Tension m Holes Web Flange No E 0 Diameter 0 00 f 0 000 Mm Iotal Height 0 000 0 000 Mm m Correction Factor Kt 1 0 X gt Type in the number and diameter of holes in the webs and flanges and the total height of holes will be computed automatically or gt Type the total height of holes in the webs and flanges directly gt Choose a value for the correction factor kt if required gt Click OK Page 40 Chapter Four AS4100 NZS3404 Compression AS4100 and NZS3404 Multiframe Steel Codes splits the compressive design of a member to AS4100 and NZS3404 into three design checks You may choose to check the section capacity and or the member capacities about the major and minor axes When checking or designing members for compression it is necessary to specify the effective length and unbraced length of the member To
42. used by Multiframe Steel Codes Page 63 Chapter Six BS5950 Web Stiffener Spacing BS5950 When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Load Height BS5950 When checking or designing a member for bending you may need to specify the load height position This is used in determining the effective lengths of segments or sub segments along the member Bending Dialog BS5950 To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu x Bending r Lateral Restraints e Lateral Restraints Segments m em res a 0 000 Lateral Lateral 2 5 099 Lateral Lateral Unbraced Length Lb 5 099 m mLT 41 000 m Stiffener Spacing s 4 a mm If the member is fully braced against lateral torsion buckling gt Select the Member is fully laterally restrained option or if the location of lateral bracing along the member is to be specified gt Select the Position of Lateral Restraints option To add new restraint to the member gt Position the cursor with the table and click the Insert button to add a lateral restraint to the member gt Select the po
43. vertical axis of the member For design to Eurocode 3 it is assumed that the Y axis is the major axis and Z is the minor axis Design Checks Eurocode 3 The types of checks are grouped into the categories Tension Compression Bending Torsion and Buckling The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Bending Eurocode 3 The design of a member for bending is divided into eight design checks These check the flexural shear and combined flexural shear capacity of the member about the major and minor axes and the combined biaxial bending and axial force and the combined biaxial bending shear and axial force Each of these checks may consider one or more limit states depending upon the section and the actions within the member When performing a bending check it is necessary to specify how lateral buckling of the member is resisted Restraint could be provided by other members purlins girts or by other structural elements that are not modelled in Multiframe such as concrete slabs Multiframe Steel Codes provides three methods of specifying how a member is restrained against lateral buckling The user may specify that the member is fully restrained against lateral buckling in which case no lateral buckling checks will be performed Page 115 Chapter Nine User Code Page 116 The location and type of lateral restraints applied to the member in which case M
44. will be applied to the member enforcing the slenderness of the member to be less than 300 Bolt Holes LFRD When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other openings within the section If the members contain significant areas of boltholes which need to be taken into account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes The net area of the section is the gross area minus the combined area of boltholes in the flange and web Page 53 Chapter Five LRFD Page 54 The reduction in area can be specified by setting the number and diameter of holes in the web or flanges or the member Alternative the user may override this and directly specify the height of holes across the flanges and webs of the cross section These heights are multiplied by the thickness of the section to determine the total reduction in area of the section The initial value for the area of boltholes is zero Reduction Coefficient LFRD When checking or designing a member for tension using LRFD you need to specify the reduction coefficient for the distribution of forces at the ends of the member This coefficient is used to factor the net area in order to compute the effective area The reduction coefficient U has a default value of 1 0 Tension Dialog LFRD To enter the properties for tens
45. 00 NZS3404 gt For each deflection check select the axis about which the deflection will be checked gt Type in values for the deflection limits gt Click OK Seismic NZS3404 The design of a member for seismic actions is divided into four design checks and four design constraints The four design checks consider the axial force limits of clause 12 8 3 1 and the user can choose to check the member for the General Axial Limit clause 12 8 3 1 a Axial Compression Limit for both major and minor axes clause 12 8 3 1 b and the Axial Force Limit clause 12 8 3 1 c The Axial Force Limit is applied using N N The four design constraints check the member for the Beam Material and Section Geometry requirements of clauses 12 4 1 12 5 1 and 12 7 2 1 The user can select which of these constraints are to be applied to the design of a member via the Seismic dialog When checking or designing members using NZS3404 it is necessary to specify the category of a member The category of a member is specified by choosing the appropriate category from the list provided in the Seismic Dialog The default category for all members is category 4 NZS3404 Seismic Dialog To set the seismic design properties of a member gt Select the required members in the Frame window gt Choose Seismic from the Design menu Page 43 Chapter Four AS4100 NZS3404 Seismic Member Category Category 4 Non ductile
46. 2t cm2 Page 17 Chapter Two Using Steel Designer Setting Design Constraints Steel Design uses the concept of Design Constraints to describe any design requirements that are not dependent upon the design actions and can be tested independently of the load cases Design Constraints include constraints that may be imposed by the designer upon the dimensions of a member as well as any constraints that may be imposed by various design checks 1 e a slenderness check that may be required as part of a bending design Design Constraints are applied when Designing and Checking a member The calculations associated with Design Constraints are output to the design report These calculations are performed at the start of the design before considering the design checks for each load case When using Brief Reporting the calculations for failed design constraints are output to the report With detailed or full reporting the calculations for all Design Constraints are shown in the report The status of Design Constraints which were tested when Designing or Checking a member are displayed in the Constraints column in the Design Efficiency table If no constraints were checked for a particular member a dash is shown is this column Otherwise this column displays the number of Design Constraints that were not satisfied as part of the design checks Setting Section Constraints When designing a member to determine the lightest weight section that m
47. Grade from the Design menu Steel Grade Steel Grade m Grade Standard AS51397 54 Steel Grade G250 x Strength Ey 250 000 MPa Fu 320 000 MPa m Fabrication Cold Formed y In this dialog you can either gt Choose a standard and steel grade from the drop down menu or gt Type in values for F and E Finally gt Choose the method of fabrication to indicate the state of residual stress in the section gt Click OK If you choose a standard grade of steel the F and F values will be automatically entered for you The initial value for the steel grade for all members is AS1397 grade 250 Page 85 Chapter Seven AS NZS4600 Page 86 Code Checks AS NZS4600 When carrying out code checks to AS NZS4600 Multiframe Steel Codes uses the following clauses of to check your structure No other checks are performed unless they are specifically listed below AS NZS 4600 Australian New Zealand Standard AS NZS4600 2005 Cold formed Steel Structures Standards Australia 30 December 2005 Clauses used are 3 1 3 5 Design Checking Procedure The design checking procedure is as follows The design actions are calculated through the first order analyses and a second order analysis should be used for sway frames For major and minor bending section checks the design bending moment is checked to be less than the nominal section moment design capacity as found using clause 3 3 2 For
48. I LL D tw D tw D tw D t 0 6 Area 2 B tf B tf 2 B tf B t 2 D tf 10 Chapter Two Using Steel Designer Chapter 2 Using Multiframe Steel Codes This chapter describes how to use Multiframe Steel Codes with step by step instructions on the basics of using the program in the following sections e Design Procedure e Working with Design Members e Setting Design Properties e Setting Design Properties e Setting Section Type e Setting Steel Grade e Setting Design Constraints e Setting Section Constraints e Setting Frame Type e Setting Allowable Stresses e Setting Acceptance Ratio e Setting Capacity Factors e Checking a Frame e Designing a Frame e Printing e Saving your Work e Saving the report Design Procedure The basic procedure for checking or designing a frame using Multiframe Steel Codes is as follows Set up the structure and loading Carry out the analysis Check the results to ensure your structural model is correct If necessary group members into design members Enter the design information such as effective lengths steel grades etc Carry out the design checks or search for the optimum sections When you use the Check or Design commands you have the option of specifying which design checks will be carried out The types of checks are grouped into the categories Bending Tension Compression Combined Serviceability AS4600 and NZS3404 only and Seismic NZS3404 only The design checks listed with
49. LRFD code The combined cases of Torsion Biaxial Bending and Axial loads are detailed in Chapter H The resistance of a section to resistance torsional loading is calculated separately in accordance with Clause H3 Biaxial Bending and Axial loading capacity is a combination of the respective capacity checks carried out in previous chapters in accordance with Clause H1 For Doubly and Single Symmetric Members in Flexure and Tension the increase in the value of Cp varies between the LRFD and ASD versions of the code This is detailed in Clause H1 2 Page 113 Chapter Nine User Code Chapter 10 Eurocode 3 This chapter describes the implementation of the EN 1 1 1993 Specification for Structural Steel Buildings within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by the code e Notation e Design Checks e Bending e Tension e Compression e Serviceabilit e National Annex e Default Design Properties e Code Clauses Checked Notation Eurocode 3 The notation used in Multiframe Steel Codes generally follows that used in the EC3 design code Use has been made of subscripts to clarify the axis of the member to which a quantity refers For example the nominal flexural strengths about the Y and Z axes are denoted My ra and M ra respectively The geometric axes of a member are denoted as the Y and Z axes where Y represented the horizontal axis of the member and Z the
50. Multiframe Steel Codes Windows Version 16 User Manual O Bentley Systems Incorporated 2013 License amp Copyright Multiframe Steel Codes software amp User Manual O 2013 Bentley Systems Incorporated Table of Contents IEN FE datar ii 111 ablenne eee ee de v A Bemtgen a eE e E EA OA RE E E REENE 1 Chapter 1 Getting arte ageet deed ENEE e EEE E Eesi eens 3 About Multiframe Steel Codes AAA 3 IK EE 3 Installing Multiframe Steel Codes AAA 4 Starting Multiframe Steel Codes AAA 4 Adding or Removing Steel Design Codes AA 4 Design OVERVIEWS x gesscbinreseleiceetcieeteuseleendscaasebavacousanng dias te ES E A 4 Design Members analitica inicia 4 Bending CHECKS eseina T R EE E E 4 Tensi n e 4 Compression Checks iratsi eese era a EE Eur 5 Combined CHECKS geed ere enno erra EE EENEG 5 Serviceability Checks isese EE E EEE e 5 Seismic CHECKS ege e A E EEEa 5 Checkin a member srren oeg aena eT rrp gu 5 D sigming a member sonsir erit a a a Ra E EENS Eea ias 5 Repo cirio T E oi 5 WMO EE 6 Frame Wat OW EE 6 Data Window aneren Ts e E EE E mittens 6 Result WOW ER E E E 6 Pl t Ate EE 6 Report Wind OW sieeve Siesacte desi vec doit 7 Design Members gute EE EE dE Ginetta E H Viewing Results Using Design Members 8 Design Member Symbol 8 Rendering Design Members coooconcnnncnnoconoconacnnonnnoncno nono nono nono noconncnnncnnncnnccnnos 9 Coordinate S Stems consigna aida paid lia iii ua 9 Properties tor Desig durara li 9 O 10
51. actor AS4100 and NZS3404 oe eeeeeeeseecneecnseceseceseenseens 40 Tension Dialog AS4100 and NASA 40 Compression AS4100 and NZ 41 Unbraced Length AS4100 and NZS3404 oe eeeeseeeneeeneeceseceseceseenseens 41 Compression Dialog AS4100 and NASA 41 Combined Actions AS4100 and NZS3404 ooconncccocococcconnconncnoncnoncnnn crac nono nono ccnnnos 42 Serviceability AS4100 and NZS3404 00s eesecsseceseceecesecseeessneesneseneeeneeenaes 42 Serviceability Dialog AS4100 and NASA 42 Seismic NZS3404 EE 43 NZS3404 Seismic Dialogs ee d fesse atu dee EEN 43 Default Design Properties AS4100 and NASA 44 Code Clauses Checked AS4100 and NZS3404 ooococccocccoccconnconnnnnncnnnnnnn nono nonononnnos 45 AS4100 Clauses Checked sccriniiiacictd rita 45 NZS3404 Clatises Ch cked speroni tertenia iiaei nea eE E E ane 46 Chapter 5 ERED ii A A a a a a aa 49 Notation EERD EG 49 Design Checks LERD iis nancial aide Sable an sa aia ges 49 Bending LEERD ont ini ee 49 Lateral Restraints LFRD AA 50 Unbraced Length Ly and Bending Coefficient C LPRID 51 Web Stiffener Spacing LERD ooooonccnnccccocanoconoconancnonnnonnnnnncnnncon nono nccnnacnnc o 51 Bending Dialog PR 51 Generate Lateral Restraints Dialog LFRD A 52 Tensi n LPR Due EE ee e E eel AE 53 Bolt Holes LERD shes esi rs elit oe ie aie ah es ene 53 Reduction Coefficient LFRD 00 0 ee ee eeeeeeeeeeseeeseeeseeeseecsaecnaecnaeenseensaees 54 Tension Dialog LERD 0 ia
52. aken as 1 16 in 2mm greater than the nominal dimension of the hole For a chain of holes extending in a diagonal or zigzag line the net width of the section is obtained by deducting the sum of the diameters of all holes in the chain and adding for each gage space in the chain the quantity s 4g where s is the longitudinal centre to centre spacing pitch of any two consecutive holes and g is the transverse centre to centre spacing gage between fastener gage lines The reduction in area can be specified by setting the number diameter pitch and gage of holes in the web or flanges of the member Shear Lag Factor AISC 2005 2010 When checking or designing a member for tension using AISC 2005 you need to specify the reduction coefficient for the distribution of forces at the ends of the member This coefficient is used to factor the net area in order to compute the effective area The Shear Lag Factor U has a default value of 1 0 Tension Dialog AISC 2005 2010 To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Tension H Tension Holes Flange No Diameter Mole Pitch s Gage 9 Shear Lag Factor U gt Type in the number and diameter of holes in the webs and flanges Chapter Five LRFD code gt If the holes extend in a diagonal or zigzag line check the Holes in Diagonal Line box and enter the pitc
53. al The buckling cases of Compression Buckling Lateral Torsional Buckling and Bending and Compression buckling are checked in accordance with Chapter 6 3 The Bending and Compression buckling interaction factors are calculated by either Method 1 detailed in EN 1993 1 1 Annex A or Method 2 detailed in EN 1993 1 1 Annex B The decision as to which method to use depends on which National Annex is used or can be manually selected Chapter Nine User Code Chapter 11 User Code User Codes Concepts At times you may find you want to carry out design checks which are different from those prescribed in the standard codes To facilitate this Multiframe Steel Codes has an additional code named User which lets you enter design rules and check members according to these rules User Code Procedures To activate the User code gt choose User from the Code menu Now whenever you do any checking or designing Multiframe Steel Codes will use the User code rules to determine a member s efficiency You can view and edit the design rules in the User code by choosing the Edit User Code item from the Code menu The rules in the User code are grouped into the four groups which appear in the Check and Design dialogs that is Beams Ties or tension Struts or compression and Beam Columns or combined To edit the User code gt Choose Edit User Code from the Code menu Edit User Code al ES Bending Tension i Compress
54. al design code replacing the previously separate Load and Resistance Factor Design LRFD and Allowable Stress Design ASD codes The only differences between the application of these two codes are in the use of design capacity factors and for the calculation of C for the use in calculation of resistance to biaxial bending combined with a axial force The updated AISC 2010 code is also implemented In the LRFD version of the code the allowable strength is given by P P Where is the resistance factor always less than 1 0 P the design strength For ASD calculations the allowable strength is given by P P Q Where Q is the safety factor always greater than 1 0 P the design strength Values for resistance factors LRFD and safety factors Q ASD for the various strength checks are set in Multiframe Steel Codes e Notation e Design Checks e Bending e Tension e Compression e Combined Actions e Serviceability e Default Design Properties e Code Clauses Checked Notation AISC 2005 2010 The notation used in Multiframe Steel Codes generally follows that used in the AISC design code Use has been made of subscripts to clarify the axis of the member to which a quantity refers For example the nominal flexural strengths about the X and Y axes are denoted M and Mny respectively The geometric axes of a member are denoted as the X and Y axes where X represented the horizontal axis of the member and Y the ver
55. and or the behaviour of the Frame Plot Data and Results windows is extended and the Report window is used to display a summary of the design checks made by Multiframe Steel Codes You can also paste text and graphics into the report to help document your calculations The following sections document the additional content and behaviour of the windows in Multiframe when Multiframe Steel Codes is activated Frame Window When using Multiframe Steel Codes the Frame window sets up the design properties for the members in the frame You can do this by selecting members and then using the items in the Design menu to set the various design values You can also change the design properties of a member by double clicking on it in the Frame window This will produce an extended Member Properties dialog that contains separate tabs for setting many of the design options The same dialog appears if you choose Design Details from the Design menu Data Window The Data window includes an additional table named Design Details You can display this table by choosing Design Details from the Data sub menu under the Display menu This table displays all of the design information required for each member so that Multiframe Steel Codes can carry out the design checks You can change this data by clicking on the value you wish to change typing in the new value and typing Enter You may also copy and paste data to and from the table Numbers in this table that
56. are displayed in Italics in the Cb Cmx and Cmy columns will be calculated by Multiframe Steel Codes you do not have to enter them If you wish however you can override the calculation of these values by typing in a value to be used Any values you enter will be displayed in normal type To revert to the automatic calculation of any value type in a value of zero Result Window In addition to the tables of results displayed in Multiframe the Result Window contains an additional table named Design Efficiency If a member was checked for its compliance to a code then this table displays the efficiency for each design check If Multiframe Steel Codes was used to find the optimal section size then the table displays the optimal section as well as the efficiency of that section Plot Window With Multiframe Steel Codes there is an additional display function in the Plot window that lets you display a graphical representation of the efficiency of the members relative to the design code requirements Chapter One Introduction You can display efficiency by choosing the required item from the Efficiency sub menu under the Display menu This displays the same information that is displayed numerically in the Efficiency table in the Result window Multiframe Steel Codes uses a colour display to show the stress or deflection level in the member relative to its allowable value The scale on the right hand side of the window indicates the relationship bet
57. ay be used you may wish to apply some constraints to the way the sections are selected For example you may wish to limit the section s depth or width or you may wish to ensure that a group of members all use the same section To constrain the selection of a member s section gt Select the required members in the Frame window gt Choose Constraints from the Design menu Constraints E Constraints TF Max Depth omg mm I Min Depth om ini TC Max Width 250 0000 pas Min Width 250 000 mm Jo Make sections te same gt Check the boxes corresponding to the sizes you wish to constrain gt Type in the limits for the sizes you wish to constrain gt If you wish to make the sections the same check the Make sections the same check box 18 Chapter Two Using Steel Designer gt Click OK The initial value of constraints is for no limits on the sizes of sections and all members are free to be designed using a different section Name Max The maximum depth of section which may be Depth of the Depth chosen when using the Design command initial section Min The minimum depth of section which may be Depth of the Depth chosen when using the Design command initial section Max The maximum width of section which may be Width of the Width chosen when using the Design command initial section Min The minimum width of section which may be Width of the Width chosen when using the Design command initial section Setting F
58. be changed to the optimal sections After using this command you will have to re analyse the frame to determine the effect of your change on the structure 24 Chapter Two Using Steel Designer The user can override the design and specify the optimal section for a member using the command from the Design menu in which case the select section dialog will be displayed As this command does not invalidate the results of analyses 1t can be used to temporarily store the next section shape to be allocated to a member In this way other members in the frame can be investigated before having to reanalyses the structure Tips On Optimisation When you use the Design command Multiframe Steel Codes will try to find the lightest weight section in a member s group which will satisfy the design requirements If there are a large number of sections in the group this may take some time If you use the options to constrain the width or depth of the optimum section Multiframe Steel Codes will automatically skip the check for any sections which don t satisfy these criteria This means you can speed up the optimisation greatly by specifying constraints for the size of the section For example if you are selecting an optimum section from the W sections in the United States Section Library which contains a large number of sections specifying an upper and lower bound for the depth will let Multiframe Steel Codes automatically skip most of the sections and quickly f
59. be generated Page 65 Chapter Six BS5950 Page 66 Generate Lateral Restraints xj m End Restraints Top Lie OOO OE Bottom JLaed d Torsion JUnrestraned zl m Intermediate Restraints Top Lateral Bottom fisess zl Torsion JUnrestraned zl Offset ID m Spacing D a L 3 m Cancel gt Select the type of restraints to be used at the ends of the member gt Select the type of restraints to be used at intermediate points within the member gt Enter the offset length at which the first intermediate restraint will be positioned Leave this field as zero if offset is the same as the spacing gt Enter the number and spacing between the intermediate restraints gt Click OK All lateral restraint applied to the member will now be regenerated and will replace all existing restraints Tension BS5950 The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the flange or web of the member and a correction factor to account for the distribution of forces at the ends of a member Bolt Holes BS5950 When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other openings within the section If the members contain significant areas of boltholes which need to be taken i
60. ceed a specified deflection limit Serviceability Dialog BS5950 To set the design properties of a member for serviceability gt Select the required members in the Frame window gt Choose Serviceability from the Design menu Serviceability xj Serviceability Primary Deflection Check Lz250 mm Minor axis deflection Secondary Deflection Check Major axis deflecti s eflec e E 1 250 Ge Minor axis deflection gt For each deflection check select the axis about which the deflection will be checked gt Type in values for the deflection limits gt Click OK Default Design Properties BS5950 There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Default Design strength of the section s steel 235Mpa Minimum Tensile Strength of the section s steel 340Mpa Page 72 Chapter Six BS5950 section s strong axis section s weak axis about the section s strong axis length about the section s weak axis length Lateral The lateral restraints acting on the member Each end of restraints the member is fully laterally restrained at both flanges e length torsional buckling or top flange s Spacing of web stiffeners This is the spacing of any stiffeners along the web of a beam stiffeners No of Flange The number of holes in the flanges of the section Holes Diameter of Diamet
61. des a step by step description of how to modify the design properties used by the code e Setting Properties e Bending e Tension e Compression e Combined Actions e Design Properties e Steel Grade e Code Checks e References Setting Properties AS NZS4600 Before doing the checks it is necessary to enter basic design data such as effective length grade of steel etc This information can either be entered in the Frame window by selecting members and using the commands under the Design menu or it can be entered in tabular form in the Data window All of the windows and commands which are common to Multiframe work the same way in Multiframe Steel Codes You have all the display options of Multiframe and facilities to help you select the required members using clipping masking etc In general you can not change the frame or its loading in Multiframe Steel Codes the only change you can make is to change the section for a member If you do change a section you will need to re analyse using the Analyse command Although most of the design variables are pre set to the most commonly used values you will probably want to enter the design information for at least some of the members in the frame that you wish to check You set design variables by selecting the members you wish to change and then choosing the appropriate command from the Design menu There are a number of design variables which are used when doing checking to the code A
62. determining the capacity of the member The laterally unbraced length L and bending coefficient C You may need to specify a number of properties relating to the location and type of lateral restraints and the stiffener spacing along the member Lateral Restraints LFRD If the spacing of lateral restraints along the member is specified Multiframe Steel Codes uses this information to break the member up into a number of spans in order to determine lateral torsion buckling capacity of each span In Multiframe Steel Codes these spans are known as segments Each lateral restraint specified by the user is assumed to provide bracing against lateral displacement of the critical flange and or prevent twist of the cross section At any cross section the critical flange is the flange that in the absence of any restraint at that cross section would deflect the furthest during buckling of the member In most members the critical flange will be the compression flange However for a cantilevered member the critical flange is the tension flange For each restraint located along a member the user must specify the type of restraint As this depends upon which flange is the critical flange which is not know a priori the user must specify the type of lateral restraint that would be present at a section if e The top flange was the critical flange and e The bottom flange was the critical flange In LRFD no distinction is made between different t
63. e The table includes steel grade effective and unbraced lengths and limits on the size of the section for the member Results Member Efficiency Display a table in the Results window of the computed efficiency for each of the members in the frame The efficiency is the ratio of the design action or stress to the design strengths according to the current design code expressed as a percentage Efficiency See Efficiency Submenu Efficiency Submenu The items in this menu may be used to control which type of efficiency diagram is displayed in the Plot window The items listed in this menu change according to the current design code AS 4100 and NZS3404 The following items are available in the Efficiency submenu when using the Australian International version of Multiframe Steel Codes Overall Display the Overall efficiency as a colour on each member for the current load case in the Plot window Page 135 Chapter Ten Steel Designer Reference Page 136 Bending Major Section Display the Major Bending Major Section Bending efficiency as a colour on each member for the current load case in the Plot window Bending Major Member Display the Major Member Bending efficiency as a colour on each member for the current load case in the Plot window Bending Major Shear Display the Major Shear efficiency as a colour on each member for the current load case in the Plot window Bending Minor Section Di
64. e compression and will be classified accordingly If an element of the section is found to be slender the stiffness reduction factors Q Q and Q will be determined as set out in Clause E7 For Tension checks the capacity of the member is determined in accordance with Chapter D For Compression checks the capacity of the member is firstly computed for the limit states of flexural buckling about the major and minor axis is accordance with clause E3 The capacity of the member for the limit state of flexural torsional buckling is then computed using clauses E4 The compressive capacity of the member is regarded as being the minimum capacity determined for these three limit states For Flexure checks the provisions of Chapter F are adhered to Major and minor flexure checks are performed separately The capacity of a member for the limit states of Yielding Lateral Torsional Buckling Flange Local Buckling Tension Flange Yielding Flange Local Buckling and Web Local Buckling is computed Not all limit states are applicable to every cross section These are detailed in Table F1 1 In addition flange local bucking will only be considered for sections with non compact flanges Similarly web local buckling will only be considered for sections with non compact webs The design for Shear is carried out in accordance with Chapter G Major and minor shear checks are performed separately Specified stiffener spacings are accounted for Chapter Five
65. e less than the nominal member moment design capacity as found using clauses 5 3 and 5 6 Clause 5 6 3 and clause 5 6 4 are NOT considered For major and minor shear checks the design shear force is checked to be less than the nominal shear capacity found from section 5 11 The flange restraint factor af of clause 5 11 5 2 1s always set to 1 0 For tension checks the design axial tension force is checked to be less than the nominal section design capacity in tension as computed using clause 7 2 For compression section checks the design axial compressive force is checked to be less than the nominal section design capacity in compression as computed using clause 6 2 For major and minor compression member checks the design axial compressive force is checked to be less than the nominal member design capacity in compression as computed using clause 6 3 Clause 6 3 4 is NOT considered For all combined action section checks the design axial force N is the maximum axial force in the member and the design bending moments Mx and My are the maximum bending moments in the member For major and minor combined section checks the design bending moment is checked to be less than the nominal section moment design capacity reduced by axial force compression or tension as computed using clause 8 3 2 and 8 3 3 For combined biaxial section checks the design bending moments are checked to satisfy clause 8 3 4 For major and minor combin
66. e major axis of the member These lines extend each side of the member for a distance that is roughly the scale of a purlin or girt Lateral restraints are also displayed in the rendered view of the frame in which they are draw to extend from each flange by approximately the size of a purlin The restraints may be labelled using a one or two letters to indicate the type of restraint e g F fixed P partial L lateral Note that lateral restraints at the end of a member are draw slightly offset from the node so that restraints at the ends of connected members may be more readily distinguished Unbraced Length L and Bending Coefficient C LFRD Instead of specifying the position of lateral restraints it may be preferable to directly set the laterally unbraced length of the member When doing this it is also necessary to specify the bending coefficient C as this can no longer be automatically determined by Multiframe Steel Codes LRFD permits a conservative value of C 1 0 to be adopted which is the default value used by Multiframe Steel Codes Web Stiffener Spacing LFRD When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Bending Dialog LFRD To set the properties for bending gt Sel
67. e member to be less than 300 Bolt Holes Eurocode 3 When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other openings within the section The net area of the section is the gross area minus the combined area of boltholes in the flange and web For a chain of holes extending in a diagonal or zigzag line the net width of the section is obtained by deducting the sum of the diameters of all holes in the chain and adding for each gage space in the chain the quantity s 4p where s is the longitudinal centre to centre spacing of any two consecutive holes and p is the transverse centre to centre pitch between fastener gage lines The reduction in area can be specified by setting the number diameter pitch and gage of holes in the web or flanges of the member Tension Dialog Eurocode 3 To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Page 119 Chapter Nine User Code Page 120 Tension Tension Holes Flange Diameter 2 500 Iw Holes in a diagonal line Spacing s 100 350 mm 200 lt Pitch p gt Type in the number and diameter of holes in the webs and flanges gt If the holes extend in a diagonal or zigzag line check the Holes in Diagonal Line box and enter the Spacing and Pitch of holes in the webs and flanges gt Click OK Compression Eurocode 3 T
68. each member for the current load case in the Plot window Minor Bending Display the Minor Bending Minor Section Bending efficiency as a colour on each member for the current load case in the Plot window Minor Shear Display the Minor Shear Bending Minor Shear efficiency as a colour on each member for the current load case in the Plot window Minor Deflection Display the Minor Bending Minor Section Bending efficiency as a colour on each member for the current load case in the Plot window Tension Display the Tension efficiency as a colour on each member for the current load case in the Plot window Slenderness Display the Slenderness efficiency as a colour on each member for the current load case in the Plot window Compression Display the Compression Section Compression efficiency as a colour on each member for the current load case in the Plot window Bending Tension Display the combined Bending Tension efficiency as a colour on each member for the current load case in the Plot window Bending Compression Display the combined Bending Compression efficiency as a colour on each member for the current load case in the Plot window Sway Display the Sway efficiency as a colour on each member for the current load case in the Plot window Help Menu Provides access to an on line help system Chapter Ten Steel Designer Reference Multiframe Steel Codes Help This command allows you to la
69. eaeeeaeeesaes 72 Code Clauses Checked Baag0a cece iaia e Area E EE E EE 73 Chapter 7 AS NZS4 600 cia ii ias ia 77 Setting Properties ASIN ZA 77 ET E RE 79 Tension AS NZS4600 ita aii ias 82 Compression ASIN ZA 83 Unbraced Length AS N ZA 83 Combined Actions ASN ZSA conc nono nona cra cronos 84 Design Properties AS NZS4600 coooooococonocccoccconoconoconoconoconcconncnnncnncnnncrnanrna cra cra nos 84 Steel Grade ASIN ZA 85 Code Checks ah Zo Ee 86 Design Checking Drocedure nono nono nono conocio roca s 86 vii viii References AS NZS4600 sccsccccccsssssvscvcsccccccssssesssccccscesssvveececcsssrensecceccees 86 apres ee Eege dee aes 89 Setting Properties AL ieia e 89 Bending EE 91 Tension AMS Ei dd ee ee ee tees 94 Compression EES euen a eet e hav tet ee 95 Unbraced Lengtb AIS Dnie ia e 95 Combined Actions AIS enee E E E Ae 96 Design Properties Alliance 96 Steel Grade AlS EE 97 Code Checks A S oi led 98 Design Checking Drocedure nono nono nono nonn nono nccnnecnnc ns 98 References AMS EE ee 98 Chapter 9 AISC 2005 201 0 ici geseis Dee Eege Ehe 101 Notation AISC 2005 2010 ance eee sofia 101 Design Checks AISC 2005 2010 0 cee cescesceseceseeeseeeseeeeaeeeaeecaeecaeenaeenaeenaeens 102 Bending AISC 2005 201 O ee es ese we es 102 Lateral Restraints AISC 2005 2010 0 eee esecssecsseceeceeceeeeseeeseeeseeeees 102 Unbraced Length Ly AISC 2005 2010 eee ce
70. ecking procedure is as follows The net area of the section is computed by subtracting the area of holes in the section The effective area is then calculated as the net area A times the Shear Lag Factor U If the member is been checked for tension of compression the slenderness of the section is checked For angle members the slenderness about either of the geometric axes is determined using the minimum radius of gyration of the section For each serviceability load case The maximum local displacement of the member is compared to the deflection limits specified deflection limits For each load case representing a strength limit state The design actions or required strengths of the member are determined as the maximum moment shears and axial forces within the member For first order analyses the design bending moments are amplified using the moment amplification factors Only moment amplification of braced frames is considered which corresponds to the situation in which no moments result from the lateral translation of the frame Amplification factors for sway frames are not considered and a second order analysis should be used for sway frames requiring moment amplification The plate elements of the section will be classified as Compact Non Compact Slender as per the requirements of Clause B4 and Table B4 1 If the moments in the member are less than one ten thousandth of the yield moments the section is considered to be in pur
71. ect the required members in the Frame window gt Choose Bending from the Design menu x Bending m Lateral Restraints Member is fully laterally restrainted Critical Bottom E Unbraced Length Eb fi 000 m Stiffner Spacing a 0 000 in Page 51 Chapter Five LRFD gt Select the Member is fully laterally restrained option or gt Select the Position of Lateral Restraints option and then To add new restraint to the member gt Position the cursor with the table and click the Insert button to add a lateral restraint to the member gt Select the position of each restraint gt Select the type of each lateral restraint from the combo provided in each cell or gt Click the Generate button to automatically generate a number of restraints To delete a restraint from the member gt Position the cursor within the table on the lateral restraint to be deleted and click the Delete button gt Or select the Unbraced Length option and then gt Enter the unbraced length le gt Enter the moment modification factor coefficient am to be used in the design of this length of the member gt Choose the position of the load from popup menu gt If there are transverse stiffeners on the web type in values for the stiffener spacing s gt Click OK Generate Lateral Restraints Dialog LFRD When the user selects to generate the lateral restraints fr
72. ed in Multiframe Steel Codes generally follows that used in AS4100 and NZS3404 There are some minor differences that are noted below In addition some extra notation has been introduced to help clarify the different design quantities kte Correction factor for distribution of forces in a tension member equivalent to kt in AS4100 Nexl nominal member capacity in axial compression for buckling about the major principle axis computed using a maximum effective length factor ke of 1 0 Neyl Nominal member capacity in axial compression for buckling about the minor principle axis computed using a maximum effective length factor ke of 1 0 Design Checks AS4100 and NZS3404 The types of checks are grouped into the categories Bending Tension Compression Combined Serviceability and Seismic NZS3404 only The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Bending AS4100 and NZS3404 The design of a member for bending consists of five design checks These check the section capacity of the member about the major and minor axes the shear capacity about both axes and the member or buckling capacity about the major axis When performing a bending check it is necessary to specify how lateral buckling of the member is resisted Restraint could be provided by other members purlins girts or by other structural elements that are not modelled in Mu
73. ed in plane member checks the design bending moment is checked to be less than the nominal in plane member moment design capacity as computed using clause 8 4 2 Clause 8 4 3 is NOT considered For combined out of plane member checks the design bending moment about the major axis is checked to be less than the nominal in plane member moment design capacity as computed using clause 8 4 4 For combined biaxial member checks the design bending moments are checked to satisfy clause 8 4 5 Clause 8 4 6 is NOT considered NZS3404 Clauses Checked New Zealand Standard NZS3404 1997 Steel Structures Standards New Zealand Se June 1997 including Draft Amendment No 1 August 2000 Clauses used are 4 4 4 8 5 1 5 2 5 3 5 6 5 11 6 1 6 2 6 3 7 1 7 2 7 3 8 1 8 3 8 3 12 4 12 5 12 7 and 12 8 The design checking procedure is as follows Chapter Four AS4100 NZS3404 For first order analyses the design bending moments are amplified using the factors determined using clause 4 4 2 and 4 8 2 Amplification factors for sway frames are not considered and a second order analysis should be used for sway frames requiring moment amplification The section is classified as compact non compact or slender about its major and minor axes using clause 5 2 The effective area and form factors are determined using clause 6 2 The member is checked for compliance to clauses 12 4 1 1 12 5 1 1 and 12 7 2 1 Compliance of clause 12 4 1 1 on
74. ed with clause 3 3 3 4 It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Bending AS NZS4600 When performing a bending check you may need to specify the location and type of lateral restraints acting on the member It is also necessary to enter the stiffener s information To determine the moment member capacity of a member it is necessary to know the spacing of any lateral restraints 1f any along the member The restraints could be provided by purlins girts or other structural elements which are not modelled in Multiframe Multiframe Steel Codes uses this information to determine the length of segments used in the design calculations The lateral restraints acting at a particular section on a member are dependent upon which flange is the critical flange For a member segment restrained at both ends the critical flange is the flange under compression For a cantilever or a segment with an unrestrained end the critical flange 1s the tension flange For each restraint on the member the user must specify the type of restraint As this depends upon which flange is the critical flange the user must specify the type of lateral restraint that would be present at a section if 1 the top flange were the crit
75. eecsseceseceseceseceseeeeeeeees 103 Web Stiffener Spacing AISC 2005 2010 cooooooncconoccnocononcconoconcconncnnnananannss 103 Bending Dialog AISC 2005 2010 eee eeseesecssecnsecesecesecsseeeseeeseeeseeeees 103 Generate Lateral Restraints Dialog AISC 2005 2010 s es 105 Tension AISC200 2010 cia 105 Bolt Holes AISC 200202010 106 Shear Lag Factor AISC 2005 2010 cooooonoconocococononcconnconnconncnnncnnnnrnaccnn conan 106 Tension Dialog AISC 20020010 eseesecssecnsecsseceseceseesseeeseeeseeeees 106 Compression AISC 20010 107 Unbraced Length AISC 2002 2010 107 Compression Dialog AISC 20001 107 Combined Actions AISC 20001 110 Serviceability AISC 2005 2010 nono E A a aE 110 Serviceability Dialog AISC 20001 110 Default Design Properties AISC 20001 110 Code Clauses Checked AISC 2002 2010 111 Chapter 10 Eur code viii E 115 Notation BUrocode Simca El arias 115 Design Checks Eurocode 3 115 Bending Eurocode deis ii anti 115 Lateral Restraints Eurocode 3 116 Unbraced Length Ly Eurocode 3 117 Web Stiffener Spacing Eurocode 3 117 Bending Dialog Eurocode 3 117 Generate Lateral Restraints Dialog Eurocode 3 118 Tension Burocode Finis eat stent sation EE 119 Bolt Holes Burocode 3 vic osc nace 119 Tension Dialog Eurocode 3 119 Compression Butocode Fist nia 120 Unbraced Length Eurocode 3 120 Compression Dialog Eurocode 3 121
76. eeeeeeeeeeeseecaeecaaecnaecaecnaeenseees 28 Tensi n ASD and E RRE 28 Bolt Holes ASD and Al penere la eria Ce Ea E EEA 29 Area Reduction ASD and AIJ oo eee eeeeeeceeeneeeeeeneeeseecaaecsaeseaeenaeenseees 29 Tension Dialog ASD and AU 29 Compression AS Dand Aun 29 Compression Dialog ASD and AU 30 Combined Actions ASD and AU 31 Default Design Properties ASD and Al oes ceeceseceseeeeeeeseeeeneeeaeeeseeeneeenaes 31 Code Clauses Checked ASD and AIJ oo cee cesceseceseceseeeseeeseeeeneeeneeeneeeaeeenaes 32 ASD Claus s Checked cid 32 ALS Clatises TEE 33 Short Term oads tor Al iia rs eee ah Re 34 Chapter 4 AS4100 and NZS3404 accordance 35 Notation AS4100 and NASA 35 Design Checks AS4100 and NASA 35 Bending AS4100 and NZS3404 oo cesecssecsseceeceseceseeeseeeseesseeseneesaeeeaeeenaeenaes 35 Lateral Restraints AS4100 and NZS3404 oie eeeeseecnsecnsecnseceseeeeeens 36 Unbraced Length le and Bending Coefficient At AS4100 and NZS3404 AE TEE eege ee EE 37 Web Stiffener Spacing AS4100 and NZS3404 coocooccnncconoconocononoconoconacanacns 37 Load Height AS4100 and NZS3404 occocconoconoconocncocnonnncnncnnncnnncnnnccnacnnenns 37 Bending Dialog AS4100 and NZS3404 ccocconnccnocccocnnocncnonononcnnnoconocnocnecns 37 Generate Lateral Restraints Dialog AS4100 and NZS3404 00 ee 39 Tension AS4100 and NZS3404 A 39 Bolt Holes AS4100 and NZS3404 ooo eeeeseeeseeeneeeeecnaecnsecsaecnseenseens 40 Correction F
77. ember Chapter Eight AISI Compression AISI To determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by La K L and Ly K L where Lex and L are the lengths of the member in x and y direction respectively K and K are the two effective length factors for the major and minor axes respectively The initial values of K and K are 1 0 Unbraced Length AISI To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Lex corresponding to the spacing of restraints preventing compression buckling about the x x axis and L y corresponding to the spacing of restraints preventing compression buckling about the y y axis To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu Compression
78. ember is fully laterally restrained Lateral Restraints Segments Position m Top Bottom Torsion 1 0 000 Lateral Lateral Unrestrained 5 891 Lateral Lateral Unrestrained gt Insert Delete Generate Unbraced Length Stiffener Spacing s 0 000 mm gt Select the Member is fully laterally restrained option or gt Select the Position of Lateral Restraints option and then Page 117 Chapter Nine User Code To add new restraint to the member gt Position the cursor with the table and click the Insert button to add a lateral restraint to the member gt Select the position of each restraint gt Select the type of each lateral restraint from the combo provided in each cell or gt Click the Generate button to automatically generate a number of restraints To delete a restraint from the member gt Position the cursor within the table on the lateral restraint to be deleted and click the Delete button To define the unbraced length gt Select the Unbraced Length option and then gt Enter the unbraced length L To define the stiffener spacing gt If there are transverse stiffeners on the web type in values for the stiffener spacing a gt Click OK Generate Lateral Restraints Dialog Eurocode 3 When the user selects to generate the lateral restraints from the Bending dialog the Generate Lateral Restraints dialog is displayed This dialog enables the u
79. ength To add new restraint to the member or To delete a restraint from the member gt Select the position of each restraint To define the unbraced length gt Enter the unbraced length A To define the stiffener spacing Page 104 gt Select the Member is fully laterally restrained option or Select the Position of Lateral Restraints option and then gt Position the cursor with the table and click the Insert button to add a lateral restraint to the member gt Select the type of each lateral restraint from the combo provided in each gt Click the Generate button to automatically generate a number of gt Position the cursor within the table on the lateral restraint to be deleted and click the Delete button gt Select the Unbraced Length option and then gt If there are transverse stiffeners on the web type in values for the stiffener spacing a Chapter Five LAFD code Generate Lateral Restraints Dialog AISC 2005 2010 When the user selects to generate the lateral restraints from the Bending dialog the Generate Lateral Restraints dialog is displayed This dialog enables the user to generate lateral restraints are a specified spacing along the member gt From the Bending dialog click the Generate button x m End Restraints Top Full ha Botton fa e m Intermediate Restraints Bottom Full y Offset jo 000 m Spacing fi 2 048 m Cance
80. er of holes in the flanges of the section Flange Holes Total Height of Total height of any boltholes in the flanges of the Flange Holes section This value may be input directly or computed automatically when the number and diameter of flange holes are specified acs o PT Holes Diameter of Diameter of holes in the webs of the section Web Holes Correction factor for the distribution of forces 1 0 Total Height of Total height of any bolt holes in the webs of the Web Holes section This value may be input directly or computed automatically when the number and diameter of flange holes are specified Fabrication The method by which the section was Rolled manufactured This describes the residual stresses in the section It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Code Clauses Checked BS5950 When carrying out code checks Multiframe Steel Codes uses the following clauses of the applicable codes to check your structure No other checks are performed unless they are specifically listed below The alternative design provisions provided by the code for combined actions checks are automatically used if the member meets the required criteria Page 73 Chapter Six BS5950 Page
81. erviceability 42 72 133 Serviceability Checks 5 Set Best Section 25 Setting Properties 12 31 44 72 77 89 Shear Area 10 Slenderness 138 Starting Steel Designer 4 Steel Designer Help 139 Steel Grade 15 85 97 133 Sway 138 T Tension 13 28 39 66 82 94 133 136 138 Tension Checks 4 U ultimate tensile strength 15 Unbraced Length 27 30 41 83 95 Unbraced Lengths 69 Use Best Sections 24 134 User 135 Y yield strength 15
82. es in the webs of the section Correction factor for the distribution of forces Web Holes Total Height of Total height of any boltholes in the webs of the Web Holes section This value may be input directly or computed automatically when the number and diameter of flange holes are specified Fabrication The method by which the section was Hot Rolled manufactured This describes the residual stresses in the section Page 57 Chapter Five LRFD Page 58 It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Code Clauses Checked LFRD When carrying out code checks Multiframe Steel Codes uses the following clauses of the applicable codes to check your structure No other checks are performed unless they are specifically listed below Checks are not carried out on composite members or tapered members Checks on mono symmetric I sections are not considered as are checks using actions computed using plastic analysis e LRFD e LRFD SAM LRFD Clauses Checked Load and Resistance Factor Design Specification for Structural Steel Buildings American Institute of Steel Construction December 27 1999 The design checking procedure is as follows The net area of the section is computed by
83. f the applicable codes to check your structure No other checks are performed unless they are specifically listed below EN 1993 1 1 2005 Eurocode 3 Design of Steel Structures Part 1 1 General rules and rules for buildings May 2005 The design checking procedure is as follows The net area of the section is computed by subtracting the area of holes in the section For each serviceability load case The maximum local displacement of the member is compared to the deflection limits specified deflection limits For each load case representing a strength limit state Page 125 Chapter Nine User Code Page 126 The design actions or required strengths of the member are determined as the maximum moment shears and axial forces within the member For first order analyses the design bending moments are amplified using the moment amplification factors Only moment amplification of braced frames is considered which corresponds to the situation in which no moments result from the lateral translation of the frame Amplification factors for sway frames are not considered and a second order analysis should be used for sway frames requiring moment amplification The plate elements of the section will be classified as Class 1 2 3 or 4 as per the requirements of Section 5 5 2 and Table 5 2 In Class 4 cross sections effective widths are calculated to make the necessary allowances reductions in resistance to the effects of local buckl
84. f the unbraced lengths of the member are to be specified directly then gt Select the Unbrace Length radio button Compression Compression ky kz 1 000 Column Segments Restraints Major Axis Minor Axis yy zz Joint Position Restraint Restraint gt Type in values for ky and kz gt Type in values for Ley and Lez gt Click OK The initial values of L y and L are the length of the member The default values of k and k are 1 0 Otherwise if the design for compression is to be performed using column segments gt Select the Column Segments radio button The tabbed control in the dialog will become active The first page in this table lists the location of joints along the members and indicates if they provide restraint against column bucking about either axis of the member Page 121 Chapter Nine User Code Compression Compression C Unbraced Lengths ky 1 000 Ley fi m 1 000 Lez fi m Restraints Major Axis Minor Axis tont Poston restraint 1 0 000 Y Vv 7338 W Vv gt Enter the restraints associated with each node The restraint information is used to build a list of column segments that span between the specified restraints gt Click on the Major Axis tab This displays a table of column segments that will be used for the design of the member for compression when considering buckling about the major axis Restraints Major Axis Minor Ax
85. for each of the design codes is given in the following Chapters Installing Multiframe Steel Codes Multiframe Steel Codes is installed as part of the Multiframe Suite installer For instructions please see http www formsys com installation or the installation guide on the installation CD Starting Multiframe Steel Codes Because Multiframe Steel Codes is an add on to the Multiframe application and runs fully within the Multiframe application you can not start Multiframe Steel Codes separately After installing the required Multiframe Steel Codes code and starting the Multiframe application you will see additional menu items appear If this is not the case you have to manually enable the Multiframe Steel Codes licenses from the Licensing tab from the Edit Preferences dialog in Multiframe Only installed design codes can be selected others will be greyed out Adding or Removing Steel Design Codes If you wish to add or remove Steel Design codes you should run the original installer again and select Modify See the Installation Guide section Repairing or Modifying the installation for more information Design Overview Multiframe Steel Codes is used to check the compliance of a member or design a member to a specific steel design code Each of the steel design codes supported by Multiframe Steel Codes is divided into a number of design checks The user can specify which of these checks are performed when a member is designed o
86. formation on the methods used to check members in Multiframe Steel Codes e Australian New Zealand Standard AS NZS 4600 2005 Cold formed Steel Structures Australian Institute of Steel Construction Sydney 1998 3rd Edition Chapter Seven AS NZS4600 e Design of Cold formed Steel Structures to Australian New Zealand Standard AS NZS 4600 1996 J Handcock Australian Institute of Steel Construction Sydney 1998 3rd Edition e Design of Cold formed Steel Members J Rhodes Department of Mechanical Engineering University of Strathclyde Glasgow UK 1991 e Multiframe Steel Codess Handbook B Gorenc R Tinyou and A Syam UNSW Press Sydney 1996 6th Edition e The Behaviour and Design of Steel Structures N S Trahair and M A Bradford Chapman and Hall London 1988 Page 87 Chapter Eight AISI Chapter 8 AISI This section explains the AISI design code in Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by the code e Setting Properties e Bending e Tension e Compression e Combined Actions e Design Properties e Steel Grade e Code Checks References Setting Properties AISI Before performing design checks it is necessary to enter basic design data such as effective length grade of steel etc This information can either be entered in the Frame window by selecting members and using the commands under the Design menu or it can be entered in tabular f
87. g the ASD and AIJ codes are grouped into the four categories Bending Tension Compression and Combined Bending ASD and AlJ There are six design checks grouped under the Bending category These checks verify a member s capacity to resist bending moments and shear forces about the major and minor axes Design checks for the deflection of the member are also included in this group When performing a bending check you need to specify a number of properties relating to the unbraced length and the spacing of stiffeners on the member When using the ASD code the user may also specify a bending coefficient Design Constraints AlJ When checking or designing a member for bending compression or combined bending and compression a design constraint is automatically imposed by Multiframe Steel Codes This constraint verifies that the member satisfies the requirements of AIJ for the Width to Thickness Ratio b t of Plate Elements Unbraced Length ASD and AlJ To determine the critical buckling condition of a member it is necessary to know the spacing of any bracing if any along the member Purlins girts or other structural elements that are not modelled in Multiframe could provide this bracing Some bracing may only restrain lateral deflection in one direction It is therefore necessary to enter unbraced lengths for both axes of the section Lbx corresponding to the spacing of restraints preventing buckling about the x x axis and Lby co
88. gn member produces a local member diagram for the entire design member If the design member consists of more than one member the diagram for a single member can be examined by simply clicking on that member within the diagram 2 89 kN m 5 82 kN 35 06 mm 15 00m 34 Static Case Load Case 1 Design Member 1 D1 310UB40 4 Design Member Symbols In the Symbols dialog there are three check boxes grouped together which are dedicated to viewing design members If Design Members is checked then design members containing more than a single member are displayed in the Frame window by a patterned blue overlay If Labels is checked the labels of the design members are displayed in all the drawing windows If Numbers is checked the numbers of all the design members used in design are displayed in all the drawing windows Chapter One Introduction Rendering Design Members Design members are rendered in the Frame and Load windows as a single member Coordinate Systems Much of the design information and many of the design variables are described relative to the major and minor axes of the section used for each member This corresponds to the same terminology used to describe the properties of a section e g Ixx for moment of inertia about the major or strong axis and Iyy about the minor or weak axis Y Local Member Axes Joint 1 m Joint 2 Section a Global Axes Axes The coordinate systems corresponding to the nam
89. gt Select the required members in the Frame window gt Choose Tension from the Design menu Tension Holes No Diameter 0 000 Mmm Total Height 0 000 Mmm Correction Factor Kt 1 0 gt Type in the number and diameter of holes in the webs and flanges and the total height of holes will be computed automatically or gt Type the total height of holes in the webs and flanges directly gt Choose a value for the correction factor kt if required gt Click OK The total height of holes in the webs or flanges is used to compute the cross sectional area of holes in the section This is used compute the net area of the section and also for computing the effective section modulus The initial value for the number and diameter of bolt holes is zero When checking or designing members for compression it is necessary to specify the effective length and unbraced length of the member Chapter Seven AS NZS4600 Compression AS NZS4600 To determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by La K E and Ly K Ly where Lex and L are the lengths of the member in x and y direction respectively
90. h and gage of holes in the webs and flanges gt Enter a value for the Shear Lag Factor U gt Click OK Compression AISC 2005 2010 To determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by Ley KyLex Ley KyLoy and Le K Lz where Lex and Ley are the lengths of the member in x and y direction respectively K and K are the two effective length factors for the major and minor axes respectively Le and K are the effective length and effective length factors to resist torsional buckling The initial values of K K and K are 1 0 Unbraced Length AISC 2005 2010 To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Lex corresponding to the spacing of restraints preventing compression buckling about the x x axis and L y corresponding to the spacing of restrai
91. he efficiency below which the design checks on a member have deemed to of passed This value is known as the Acceptance Ratio Any design check on the member for which the efficiency exceed this value will be marked as a failed check The Acceptance ratio for a particular member is set via the Options command in the Design menu The initial value of the Acceptance Ratio for all members is 100 Setting Capacity Factors In limit state design the design capacity is obtained by multiplying the nominal capacity by the capacity factor The capacity factor will vary depending upon the specific design check being considered The design codes generally specify maximum values for the capacity factors In some circumstances the user may wish to specify other values for the capacity Multiframe Steel Codes allows you to do this by using the Capacity Factors option from the Design menu A dialog is displayed which allows the user to change the capacity factors for each of the design checks for a strength limit state The initial values of the capacity factors are the values specified by the design codes In most likely that the capacity factors will never be modified by a user Checking a Frame Once you have set up the structure and its design properties you can check it for compliance with the code rules To check a member or group of members gt Select the required members in the Frame window gt Choose Check from the Design menu Check Ea
92. he user to specify the area of holes in the cross section and a coefficient to account for the distribution of end forces or used to computing effective net area of the section Compression When checking or designing members for compression it is necessary to specify the effective length and unbraced length of the member Combined Actions Some design codes require the user to specify a coefficient that accounts for the distribution of moments along a member Serviceability With some design codes it may be necessary to specify the deflection limits used in checking the serviceability of a member Seismic Some design codes require a member to be categorised according to the required ductility of the member For some design codes no design data is required for the design checks in a particular category and so the menu item will not be enabled In other codes there are no design checks performed within a particular category and the menu item will again be disabled Setting Design Properties Sometimes you may wish to set or review all of the design properties for a member at once This may be quicker than setting each of the design values in turn using the commands above To set all of the design variables gt Select the required members in the Frame window gt Choose Design Details from the Design menu Page 13 Chapter Two Using Steel Designer Design Member 1 Properties AS4100 shown gt Enter the design values
93. hecked ASD and AlJ no Moment modification factor used to determine U Cb Cmx m When carrying out code checks Multiframe Steel Codes uses the following clauses of the applicable codes to check your structure No other checks are performed unless they are specifically listed below ASD Clauses Checked Specification for Structural Steel Buildings Allowable Stress Design and Plastic Design American Institute of Steel Construction June 1 1989 contained in Manual of Steel Construction Allowable Stress Design 1989 9th Edition Clauses used are A5 1 A5 2 B1 B3 B5 B7 C2 DI El E2 Fl F2 F3 F4 G1 G2 G3 H1 H2 The design checking procedure is as follows The section is classified and tensile area and limiting slenderness ratios are determined according to section B For major and minor bending checks the bending stress is checked to be less than the allowable Fb as found in sections F1 F2 and F3 For major and minor shear the shear stress is checked to be less than the allowable Fs found from section F4 The shear stress is computed using a shear area as shown above For major and minor deflection due to bending the maximum deflection is checked to be less than L 300 No specific check is made for cantilevered members For tension checks the tensile stress is checked to be less than the allowable Ft on both the gross and net areas as computed in section D1 For slenderness checks the slenderness
94. hen performing a bending check it is necessary to specify how lateral torsional buckling of the member is resisted Restraint could be provided by other members purlins girts or by other structural elements that are not modelled in Multiframe such as concrete slabs Multiframe Steel Codes provides three methods of specifying how a member is restrained against lateral buckling The user may specify e That the member is fully restrained against lateral buckling in which case no lateral buckling checks will be performed or e The location and type of lateral and torsional restraints applied to the member in which case Multiframe Steel Codes will appropriately divide the member into a number of spans and consider the capacity of each of these spans in determining the capacity of the member or e The laterally unbraced length Lp and moment modification factor m7 You may also need to specify a number of properties relating to the location and type of lateral restraints and the stiffener spacing along the member Page 62 Chapter Six BS5950 Lateral and Torsional Restraints BS5950 To compute the buckling capacity of a member it is necessary to know the spacing of any lateral and torsional restraints if any along the member The restraints could be provided by purlins girts or other structural elements which are not modelled in Multiframe Multiframe Steel Codes uses this information to determine the length of segments used in the des
95. hich satisfy the design criteria A word of caution Multiframe Steel Codes is a very useful aid to the design of steel structures Itis NOT an automatic design tool and it should be used in conjunction with professional engineering judgment to produce well designed frames Design Codes Multiframe Steel Codes supports checking and designing of your structure in accordance with a range of design codes At present Multiframe Steel Codes allows you to use e AlJ Architectural Institute of Japan 1979 e ASD American Institute of Steel Construction Allowable Stress Design 9th Ed 1989 e AS4100 Australian Steel Design Code Standards Australia 1990 e LRFD American Institute of Steel Construction Load and Resistance Factor Design December 27th 1999 e NZS 3404 New Zealand Steel Design Code Standards New Zealand 1997 e BS5950 British Steel Design Code British Standards Institution 2000 e AS NZS4600 Australian New Zealand Steel Design Code Australian Standards Institution 2005 e AISI North American Specification for the Design of Cold formed Steel Structural Members AISI Standards 2001 Edition e A user definable allowable stress code Other design codes will be supported in future releases of Multiframe Steel Codes Page 3 Chapter One Introduction Only design codes licensed by the user will be active in the Code menu A detailed description of the design checks performed by Multiframe Steel Codes
96. ical flange and 11 the bottom flange was the critical flange To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Page 79 Chapter Seven AS NZS4600 Bending Bending Stiffener s Lateral Restraints Member is Fully laterally restrained or flange fastened to sheeting for C and 2 purlins K r Purlins Reduction factor 4 Lateral Restraints Segments Position m Bottom Torsion a Lateral Lateral Unrestrained Lateral Lateral Unrestrained gt Insert Delete Generate Unbraced Lenath Ch 1 000 1 000 gt Click the type of lateral restraints gt Enter the position and type of lateral restraints for both top and bottom flange If there are transverse stiffeners on the web or flange click the stiffener tab and see the following window Page 80 Chapter Seven AS NZS4600 Bending Bending Stiffener s Stiffener Length ds Dong mm Flange Stiffener s Web Stiffener s 51 0 000 mm 51 0 000 Gm 52 0 000 mm 52 0 000 mm Number 0 Number fo Coefficients for unequal end moment Cmx 1 000 Emy 1 000 gt Enter the length of stiffener gt Enter the number of stiffeners and spacing s etc gt Enter coefficients for unequal end moment gt Click OK Lateral restraints must always be specified at the ends of the beam and so the mi
97. iffeners The number of holes in the flanges of the section Diameter Diameter of holes in the flanges of the section of Flange Holes Total Total height of any bolt holes in the flanges of the section Height of This value may be input directly or computed Flange automatically when the number and diameter of flange Holes holes are specified The number of holes in the webs of the section Diameter Diameter of holes in the webs of the section of Web Holes Total Total height of any bolt holes in the webs of the section Height of This value may be input directly or computed Web automatically when the number and diameter of flange Holes holes are specified To Depth when using the Design command initial section Depth when using the Design command initial section Width when using the Design command initial section Width when using the Design command initial section Page 78 Chapter Seven AS NZS4600 Cs Moment coefficient 1 0 for moment causing 1 0 compression on shear centre side of the centroid while 1 0 for moment causing tension on shear centre side of the centroid Coefficient depending on moment distribution in the laterally unbraced segment Coefficient for unequal end moment Coefficient for unequal end moment Purlins reduction factor For channel and Z purlins in which the tension flange is attached to sheeting the member bending capacity subjected to lateral buckling is calculat
98. ign calculations for lateral torsional buckling In Multiframe Steel Codes The restraint provided by a support is described by how it restraints the top and bottom flanges and how it restraints the cross section of the member at that location against torsion Restraints must always be specified at the ends of the member If no actual restraint exists at the end of a member then it should be specified as unrestrained Lateral restraints at the ends of a member may also be specified as providing either full or partial restraint against rotation on plan By default the ends of a member will be assumed to be laterally restraint at both the top and bottom flange but provide no resistance to on plan rotation of the member Torsional restraints at the ends of a member may be specified as unrestrained fully restrained partially restrained or frictionally restrained Partial restraints inhibit the rotation of the cross section by the connection of the bottom flange to the supports while frictional restraints resist rotation of the member about its longitudinal axis by only the pressure of the bottom flange onto its supports Refer to Table 13 of BS5950 Intermediate restraints applied to the member may provide lateral and torsional restraint No distinction is made for the on plan rotational resistance that may be provided by lateral restraints The location and type of lateral restraints can be displayed in the Frame and Plot windows The display of late
99. in each category vary according to the design code The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Page 11 Chapter Two Using Steel Designer Working with Design Members When designing a frame it is often convenient to group members together and treat them as a single member for the purposes of design This is often the case when a physical member in a frame has been subdivided into a number of members in the Multiframe model Members can be combined into a single design member in the Frame Window To create a design member gt Select the members to be grouped gt Choose Create Design Members from Group menu or gt Press Ctrl D The members that form each design member are displayed in the Design Details and Design Efficiency data tables 1 12 23 34 45 310UB40 4 i 2 310UB40 4 3 14 25 36 47 310UB40 4 4 310UB40 4 5 16 27 38 49 310UB40 4 6 310UB40 4 310UB40 4 8 310UB40 4 H 310UB404 e 4 gt Analysis Settings A Design Det 4 fy 1 2 3 4 5 6 7 8 e To delete or split design members select members that are part of the design member s and choose Ungroup Members from the Design menu Setting Design Properties Before doing the checks it is necessary to enter basic design data such as effective length grade of steel etc This information can either be entered in the Frame Load or Plot windows by selecting de
100. ind one of the right size Checking for sway when using the Design command is not recommended It is unlikely that Multiframe Steel Codes will find an optimum size member because the amount of sway is likely due to the stiffness of other members probably the columns in another part of the frame rather than the member under consideration These other members will not be changed while the current member is being checked Finding Design Values The Find command from the Edit menu can be used to automatically search through the structure to find members that have design values exceeding a specified value for the current load case You can search for actions deflections stresses or efficiencies To search for a category of members gt Choose Find from the Edit menu Find Members x Max Cancel m Find Members With abs C e Moment Mz y C ve gt Click on the pop up menu to choose the category to search for gt Click on the radio buttons to set the criteria for the search gt Click OK After searching through the frame Multiframe Steel Codes will select all of the members which meet the specified criteria Printing You can print the contents of any of the windows including the Report window Page 25 Chapter Two Using Steel Designer Printing the Report Window To print the contents of the Report window gt Ensure the Report window is in front gt Choose Print Window fro
101. ined Actions AS NZS4600 No information is required when checking or designing members for combined actions using AS NZS4600 Design Properties AS NZS4600 Sometimes you may wish to set all of the design properties for a member or group of members at once This may be quicker than setting each of the design values in turn using the commands above To set all of the design variables gt Select the required members in the Frame window gt Choose Design Details from the Design menu Design Member 1 Properties Steel Grade Constraints Serviceability Stiftener s Member Bending Tension Compression m Lateral Restraints Member is fully laterally restrained or Purlins Reduction factor flange fastened to sheeting for C a 1 000 Position of Lateral Restraints Lateral Restraints Segments Unbraced Length gt Click each tab and enter the design values gt Click OK Page 84 Chapter Seven AS NZS4600 As a shortcut you can examine and change the design details for a single member by double clicking on it in the Frame window Steel Grade AS NZS4600 To determine the allowable stresses for a member it is necessary to know the grade of steel to be used for the section This grade determines the yield strength Fy and ultimate tensile strength F of the material of the section To set the Steel Grade gt Select the required members in the Frame window gt Choose Steel
102. ing For Tension checks the capacity of the member is determined in accordance with Chapter 6 2 3 The smaller of the values for design plastic resistance without considering fastener holes and the ultimate resistance including fastener holes is used For Compression checks the capacity of the member is firstly computed using the area of the cross section for Class 1 2 or 3 cross sections For Class 4 cross sections the effective area 1s used For Bending checks the provisions of Chapter 6 2 51s adhered to Major and minor flexure checks are performed separately For Class 1 and 2 cross sections are designed to their elastic limit Class 3 and 3 cross sections to their plastic limit with Class 4 cross sections using a reduced effective Plastic Modulus At present no allowance is made for fastener holes The design for Shear is carried out in accordance with Chapter 6 2 6 Major and minor shear checks are performed separately Where shear force is present is allowed for in the combined Bending and Shear check as described in Chapter 6 2 8 The combined cases of Bending and Axial force and Bending Shear and Axial force are checked as described in Chapter 6 2 9 The Shear check is only included if present Torsion is detailed in Chapter 6 2 7 The torsional strength is a combination of the uniform torsional section resistance and the biomoment section resistance as per The Behaviour and Design of Steel Structures to EC3 by Trahair et
103. ing conventions for the various results of analysis section properties and design values are shown in the diagram above Structure coordinates and global loads are defined relative to the Global Axes member actions deflections and stresses resulting from the Multiframe analysis are defined relative to the local member axes and design values are defined relative to the section axes Whenever a design variable carries a subscript this indicates that it applies to the corresponding section axis E g fbx refers to the design bending stress about the x axis Properties for Design When checking or designing structures Multiframe Steel Codes uses sections properties stored in the Sections Library The key properties used by Multiframe Steel Codes are Property Cross sectional area Major moment of inertia Minor moment of inertia Young s Modulus Depth Breadth or Width Flange thickness Web thickness Page 9 Chapter One Introduction Major radius of gyration Minor radius of gyration Radius of gyration about weakest axis Plastic modulus about major axis Plastic modulus about minor axis When you add a section to the Sections Library you must ensure that all of the properties above are correctly entered and are all non zero Shear Area When calculating shear stresses for comparison with allowable shear stresses Multiframe Steel Codes uses the following shear areas or the full sectional area for other sectional shapes L
104. ion Cancel Combined gt Click on the button of the part of the code you wish to change gt Type in new rules or modify the existing design rules The syntax of the design rules is the same as that of the Calculation sheet in Multiframe This is very similar to the format used in most programming languages and spreadsheets The following variables are available to help you construct your design rules These variables are evaluated for each member as the member is checked Variable Value L Length of member Kx Effective length factor in major plane Ky Effective length factor in minor plane Lbx Unbraced length for buckling about the major axis Lby Unbraced length for buckling about the minor axis rx radius of gyration about major axis Page 127 Chapter Nine User Code Page 128 ry radius of gyration about minor axis E Young s modulus of steel ft maximum tensile stress fe maximum compressive stress fbx maximum bending stress about major axis fby maximum bending stress about minor axis fy yield stress of the steel fu ultimate tensile strength of the steel y height of the highest end of the member above y 0 a web stiffener spacing Cb bending coefficient Cmx major interaction coefficient Cmy minor interaction coefficient Note that all length variables marked with an asterix above are given values in the same units as the units for deflection as specified in the Units dialog This ensure
105. ion gt Select the required members in the Frame window gt Choose Tension from the Design menu x Tension m Holes Web Flange No a Diameter 0 000 0 000 Mm Total Height 0 000 0 000 mm Area Reduction Coefficient U 1 0 D Get gt Type in the number and diameter of holes in the webs and flanges and the total height of holes will be computed automatically or gt Type the total height of holes in the webs and flanges directly gt Choose or enter a value for the reduction coefficient U gt Click OK Compression LFRD Multiframe Steel Codes splits the compressive design of a member to LRFD into two design checks You may choose to check the member capacity and or the member s slenderness about the major and minor axes When checking or designing members for compression it is necessary to specify the effective length factors and unbraced lengths of the member Chapter Five LRFD code To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Lcx corresponding to the spacing of restraints preventing compression buckling abo
106. is Torsion 1 000 gt Enter the effective length factor k for each segment gt Click on the Minor Axis tab and enter the effective length factors for the minor axis column segments gt Click on the Torsion tab and enter the effective length factors for the calculation of torsional buckling resistance gt Click OK Page 122 Chapter Nine User Code Serviceability Eurocode 3 Multiframe Steel Codes provides two design checks for the serviceability of a member These design checks are used to check that the deflection of a member about either the major or minor axes does not exceed a specified deflection limit Serviceability Dialog Eurocode 3 To set the design properties of a member for serviceability gt Select the required members in the Frame window gt Choose Serviceability from the Design menu x Serviceabilty m Primary Deflection Check Em Minor axis deflection m Secondary Deflection Check Major axis deflecti Helen 7250 mm Minor axis deflection Sg gt For each deflection check select the axis about which the deflection will be checked gt Type in values for the deflection limits gt Click OK National Annex Multiframe Steel Codes allows the choice of National Annex within Eurocode 3 Default values for nations supported can be used or properties can be manually entered National Annex Dialog Eurocode 3 To
107. itial section C Moment coefficient 1 0 for moment causing 1 0 compression on shear centre side of the centroid while 1 0 for moment causing tension on shear centre side of the centroid Co Coefficient depending on moment distribution in the 1 0 laterally unbraced segment Cinx Gee l Coefficient for unequal end moment Page 90 Chapter Eight AISI Ciy Coefficient for unequal end moment Purlins reduction factor For channel and Z purlins in which the tension flange is attached to sheeting the member bending capacity subjected to lateral buckling is calculated with clause 3 3 3 4 It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Bending AISI When performing a bending check you may need to specify the location and type of lateral restraints acting on the member It is also necessary to enter the stiffener s information To determine the moment member capacity of a member it is necessary to know the spacing of any lateral restraints if any along the member The restraints could be provided by purlins girts or other structural elements which are not modelled in Multiframe Multiframe Steel Codes uses this information to determine the length of segments used in the design ca
108. its the compressive design of a member to BS5950 into three design checks You may choose to check the section capacity and or the member buckling capacities about the major and minor axes The section capacity check calculates the capacity of the members cross section to carry the axial load and computes the capacity of the members as simply the gross area times the yield strength This check is not explicitly defined in BS5950 as the capacity of the cross section will always be adequate if the member satisfies the member buckling checks However this check has been provided within Multiframe Steel Codes to help distinguish this type of failure mechanism in the design of the column To determine the buckling capacity for a column it is necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section In Steel Design the unbraced length of a member may be specified in either of the following ways By specifying a single unbraced length and effective length factor for buckling about each axis or By breaking the member into column segments and setting the effective length factor for each segment Each column segment is then designed separately for compression Chapter Six BS5950
109. k select the axis about which the deflection will be checked gt Type in values for the deflection limits gt Click OK Default Design Properties LFRD There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Yield strength of the section s steel 250Mpa Ultimate Tensile Strength of the section s steel 410Mpa Kx Effective length factor for buckling about the 1 0 section s strong axis Ky Effective length factor for buckling about the 1 0 section s weak axis Lex Unbraced length for bracing preventing buckling Member s Pe ee nem Ley Unbraced length for bracing preventing buckling Member s Pe Lee le Ley Unrestrained length for bracing preventing torsional Member s Pe A ene Lateral The lateral restraints acting on the member Each end of restraints the member is fully restrained at both flanges Lb Unrestrained length of member for lateral torsional Member s buckling length s Spacing of web stiffeners This is the spacing of 0 0 i e no Holes Diameter of Diameter of holes in the flanges of the section Flange Holes Total Height of Total height of any boltholes in the flanges of Flange Holes the section This value may be input directly or computed automatically when the number and diameter of flange holes are specified No of Web The number of holes in the webs of the section Holes Diameter of Diameter of hol
110. ks Serviceability The Serviceability command allows you to set design information regarding serviceability of the frame this is currently only used for the AS4100 and NZS3404 design codes Seismic Specify the design parameters controlling seismic design checks This is currently only used for the NZS3404 design code to specify the category of a member Design Details This command allows you to set all of the design information for the members selected in the Frame window As a short cut you can double click on a member to bring up this design dialog for that member Steel Grade Specify the grade of steel for the selected members in the Frame window You can choose from a list of standard grades or enter custom values for the yield and ultimate tensile strength Constraints Specify whether there are any constraints on the size of section which may be chosen for the selected members You can also specify 1f you require all of the selected members to be of the same section type Frame Type Specify whether the current frame is able to sway or is braced against horizontal movement Page 133 Chapter Ten Steel Designer Reference Page 134 Allowable Stresses This command allows you to specify the allowable stress increase for each load case on the structure The allowable increase is entered as a factor usually 1 33 or 1 5 Capacity Factors The Capacity Factors command allows you to modify the capacity factors
111. l gt Select the type of restraints to be used at the ends of the member gt Select the type of restraints to be used at intermediate points within the member gt Enter the offset length at which the first intermediate restraint will be positioned Leave this field as zero if no offset is same as the spacing gt Enter the number and size of spacing for the intermediate restraints gt Click OK All lateral restraint applied to the member will now be regenerated and will replace all existing restraints Tension AISC 2005 2010 The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the flange or web of the member and a shear lag factor to account for the distribution of forces at the ends of a member In addition to checking the tensile capacity of the member a design constraint will be applied to the member enforcing the slenderness of the member to be less than 300 Page 105 Chapter Five LRFD Page 106 Bolt Holes AISC 2005 2010 When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other openings within the section The net area of the section is the gross area minus the combined area of boltholes in the flange and web In computing net area the diameter of a bolthole shall be t
112. lause 2 of LRFD SAM is used to determine the tensile capacity of the member Page 59 Chapter Five LRFD Page 60 For the bending checks the shear is determined using clause 3 of LRFD SAM while the flexural capacity is determined using clause 5 of LRFD SAM The lateral torsional buckling capacity of the member for the limit state of lateral torsion buckling of unequal angle sections without lateral torsion restraint or sections modelled about their principle is not yet supported When such a section is encountered the member will have determined to have no flexural capacity The capacity of a member under combined forces is computed using clause 6 of LRFD SAM in place of the provisions in clause H or LRFD Chapter Six BS5950 Chapter 6 BS5950 This chapter describes the implementation of the British BS5950 steel design code within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by the code e Notation e Design Checks e Bending e Tension e Compression e Combined Actions e Serviceability e Default Design Properties e Code Clauses Checked Notation BS5950 The notation used in Multiframe Steel Codes generally follows that used in BS5950 Design Checks BS5950 The types of checks are grouped into the categories Bending Tension Compression Combined and Serviceability In addition a number of auxiliary combined action checks have been included that
113. lculations The lateral restraints acting at a particular section on a member are dependent upon which flange is the critical flange For a member segment restrained at both ends the critical flange is the flange under compression For a cantilever or a segment with an unrestrained end the critical flange 1s the tension flange For each restraint on the member the user must specify the type of restraint As this depends upon which flange is the critical flange the user must specify the type of lateral restraint that would be present at a section if 1 the top flange were the critical flange and 11 the bottom flange was the critical flange To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Page 91 Chapter Eight AISI Bending Bending Stiffener s Lateral Restraints Member is Fully laterally restrained or flange fastened to sheeting for C and 2 purlins K r Purlins Reduction factor 4 Lateral Restraints Segments Position m Bottom Torsion a Lateral Lateral Unrestrained Lateral Lateral Unrestrained gt Insert Delete Generate Unbraced Lenath Ch 1 000 1 000 gt Click the type of lateral restraints gt Enter the position and type of lateral restraints for both top and bottom flange If there are transverse stiffeners on the web or flange click the stiffe
114. lection of a member about either the major or minor axes does not exceed a specified deflection limit Serviceability Dialog AISC 2005 2010 To set the design properties of a member for serviceability gt Select the required members in the Frame window gt Choose Serviceability from the Design menu Serviceability x Serviceability Primary Deflection Check L 250 mm C Minor axis deflection Secondary Deflection Check Major axis deflect EEN Gen mm C Minor axis deflection Cancel gt For each deflection check select the axis about which the deflection will be checked gt Type in values for the deflection limits gt Click OK Default Design Properties AISC 2005 2010 There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Default Yield strength of the section s steel 250Mpa Ultimate Tensile Strength of the section s steel 410Mpa Page 110 Chapter Five LRFD code x Effective length factor for buckling about the 1 0 Pe ectionsrongece Effective length factor for buckling about the 1 0 W eg WEE K Effective length factor for torsional buckling 10 cx Unbraced length for bracing preventing buckling Member s about the section s weak axis length buckling length Lateral The lateral restraints acting on the member Each end of restraints the member is full
115. less than H 300 where H is the height of the highest part of the member Short Term Loads for AL As defined in the AU code if the loads are short term the allowable strength if increased by 50 To define the loads as short term click the Short Term radio button in the Load State section of the AIJ Design Check dialog To define the loads as short term gt Ensure the AIJ code is chosen Design gt Code gt AIJ gt Select one or member gt Choose Check from the Design menu gt Select Short Term from the Load State Group in the dialog shown below gt Click OK to run the design check Check Cases Lending FS Major Bending Major Shear Major Deflection Minor Bending Minor ear Minor Deflection IT Tension C Compression Slenderness Compression Combined Tension and Bending Compression and Bending Sidesway Load State Long Term Short Term Report None O Brief O Ful Chapter Four AS4100 NZS3404 Chapter 4 AS4100 and NZS3404 This chapter describes the implementation of the Australian AS4100 and New Zealand NZS3404 steel design codes within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by each code e Notation e Design Checks e Bending e Tension e Compression e Combined Actions e Serviceability e Seismic NZS3404 e Default Design Properties e Code Clauses Checked Notation AS4100 and NZS3404 The notation us
116. ltiframe such as concrete slabs Multiframe Steel Codes provides three methods of specifying how a member is restrained against lateral buckling The user may specify Page 35 Chapter Four AS4100 NZS3404 Page 36 That the member is fully restrained against lateral buckling in which case no lateral buckling checks will be performed The location and type of lateral restraints applied to the member in which case Multiframe Steel Codes will appropriately divide the member into a number of spans and consider the capacity of each of these spans in determining the capacity of the member The laterally unbraced length le and moment modification factor Qm You may need to specify a number of properties relating to the location and type of lateral restraints and the stiffener spacing along the member Lateral Restraints AS4100 and NZS3404 To determine the moment member capacity of a member it is necessary to know the spacing of any lateral restraints 1f any along the member The restraints could be provided by purlins girts or other structural elements which are not modelled in Multiframe Multiframe Steel Codes uses this information to determine the length of segments used in the design calculations The lateral restraints acting at a particular section on a member are dependent upon which flange is the critical flange For a member segment restrained at both ends the critical flange is the flange under compression For a cantilever o
117. ly considers the maximum yield stress and the maximum ratio of f f For major and minor bending section checks the design bending moment is checked to be less than the nominal section moment design capacity as found using clause 5 2 For bending member checks the design bending moment about the major principle axis 1s checked to be less than the nominal member moment design capacity as found using clauses 5 3 and 5 6 Clause 5 6 3 and clause 5 6 4 are NOT considered For major and minor shear checks the design shear force is checked to be less than the nominal shear capacity found from section 5 11 The flange restraint factor af of clause 5 11 5 2 1s always set to 1 0 For tension checks the design axial tension force is checked to be less than the nominal section design capacity in tension as computed using clause 7 2 For compression section checks the design axial compressive force is checked to be less than the nominal section design capacity in compression as computed using clause 6 2 For major and minor compression member checks the design axial compressive force is checked to be less than the nominal member design capacity in compression as computed using clause 6 3 Clause 6 3 4 is NOT considered For all combined action section checks the design axial force N is the maximum axial force in the member and the design bending moments Mx and My are the maximum bending moments in the member If any combined acti
118. m the File menu As with the other windows in Multiframe the user may review the output in the Print Preview before sending the output to the printer Saving your Work You can save your design work at any time and then open the frame later to continue where you left off To save the frame and its design information to disk gt Choose Save from the File menu The frame will be saved to disk complete with the design information you added to it Saving the report You can also save the report to disk and recall it at a later date To save the report to disk gt Ensure the Report window is in front gt Choose Save from the File menu The report will be saved to disk Use the Open command to read the report in again If you need to transfer the data in the report to another program like Microsoft Word use the Select All and Copy and Paste command to paste the data into the other program Multiframe Steel Codes places the report data on the clipboard in the RTF Rich Text format 26 Chapter Three ASD and AL Chapter 3 ASD and AlJ This chapter describes the implementation of the ASD and AU steel design codes within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by each code e Design Checks e Bending e Tension e Compression e Combined Actions e Default Design Properties e Code Clauses Checked Design Checks ASD and AlJ The design checks performed usin
119. me as the spacing gt Enter the number and size of spacings for the intermediate restraints gt Click OK All lateral restraint applied to the member will now be regenerated and will replace all existing restraints Tension AS4100 and NZS3404 The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the flange or web of the member and a correction factor to account for the distribution of forces at the ends of a member Page 39 Chapter Four AS4100 NZS3404 Bolt Holes AS4100 and NZS3404 When checking or designing a member for tension you need to specify any reduction in area due to boltholes or other openings within the section If the members contain significant areas of boltholes which need to be taken into account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes The net area of the section is the gross area minus the combined area of boltholes in the flange and web The reduction in area can be specified by setting the number and diameter of holes in the web or flanges or the member Alternative the user may override this and directly specify the height of holes across the flanges and webs of the cross section These heights are multiplied by
120. n the Plot Window when plotting the efficiency of the particular design check 22 Chapter Two Using Steel Designer Designing a Frame As well as helping to check a frame s compliance with the design rules Multiframe Steel Codes can also help you to select the lightest weight section that satisfies the design rules To design a member or group of members gt Select the required members in the Frame window gt Choose Design from the Design menu 1 29DL LSL M M M M M M KK I KKK ASD AL lt l 1 25DL 1 5DL KK KK KR lt l Self Weight Dead Load LL incl 4 5kN load at ridge 1 25DL 1 5DL lt l M M M M M M M yd M M M M Page 23 Chapter Two Using Steel Designer AS4100 NZS3404 gt Check the boxes of the design rules to be used when designing gt Shift Click on the load case names in the list to include or remove them from the check gt If you want a summary report in the Report window check the Brief or Full report radio buttons gt Click OK Multiframe Steel Codes will design each of the selected members searching through the group of sections the member s original section comes from to find the lightest section in this group that meets the design rule requirements Once the design has finished you can view the optimum section in the Best Section column in the Member Efficiency table in the Result window If you want to automatically assign all
121. ner tab and see the following window Page 92 Chapter Eight AISI Bending Bending Stiffener s Stiffener Length ds Dong mm Flange Stiffener s Web Stiffener s 51 0 000 mm 51 0 000 Gm 52 0 000 mm 52 0 000 mm Number 0 Number fo Coefficients for unequal end moment Cmx 1 000 Emy 1 000 gt Enter the length of stiffener gt Enter the number of stiffeners and spacing s etc gt Enter coefficients for unequal end moment gt Click OK Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange The different restraints acting on the member are entered into the grid using the following codes F Fully restrained P Partially restrained L Laterally Restrained U Unrestrained LR Lateral restraint with full restraint against rotation on plan LP Lateral restraint with partial restraint against rotation on plan C Continuous restraint Fully or partially restrained sections may also be specified as lateral rotational restraints Using FR Fully restrained Rotationally restrained PR Partial restrained Rotationally restrained Page 93 Chapter Eight AISI Page 94 The initial position of the loads
122. ng buckling about the major axis Restraints Major Axis Minor Axis es er a EA m 46 1 667 1 000 3 333 1 000 gt Enter the effective length factor K for each segment gt Click on the Minor Axis tab and enter the effective length factors for the minor axis column segments gt Click OK Combined Actions BS5950 The design of a member for combined actions is divided into four design checks The user can select to check the capacity of the member for biaxial bending combined with axial tension and or axial compression The combined bending and axial compression check is split into three separate calculations these determine the capacity of the member based upon in plane bucking out of plane buckling and section failure Page 71 Chapter Six BS5950 In addition to the four main combined action checks 11 auxiliary design checks may be considered These checks determine the capacity of the member using various combinations of two combined actions These include checks for biaxial bending no axial force axial tension or compression combined with bending about the major or minor axis No design properties are required when checking or designing members for combined actions using BS5950 Serviceability BS5950 Multiframe Steel Codes provides two design checks for the serviceability of a member These design checks are used to check that the deflection of a member about either the major or minor axes does not ex
123. ngth for bracing preventing buckling Member s about the section s strong axis length Unbraced length for bracing preventing buckling Member s about the section s weak axis length Page 124 Chapter Nine User Code Lateral The lateral restraints acting on the member Each end of restraints the member is fully restrained at both flanges buckling length Ne PA any stiffeners along the web of a beam stiffeners Pl o Pp E Holes Flange Holes Staggered pitch Spacing of fastener holes measured parallel to the of Flange Holes member axis s Spacing of Transverse spacing of staggered holes in the flanges Flange Holes of the section p No of Web The number of holes in the webs of the section SE Beer Web Holes Staggered pitch Longitudinal spacing of staggered holes in the webs of Web Holes of the section s Spacing of Transverse spacing of staggered holes in the webs EA GE Fabrication The method by which the section was Hot Rolled manufactured This describes the residual stresses in the section It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Code Clauses Checked Eurocode 3 When carrying out code checks Multiframe Steel Codes uses the following clauses o
124. nimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange The different restraints acting on the member are entered into the grid using the following codes F Fully restrained P Partially restrained L Laterally Restrained U Unrestrained LR Lateral restraint with full restraint against rotation on plan LP Lateral restraint with partial restraint against rotation on plan C Continuous restraint Fully or partially restrained sections may also be specified as lateral rotational restraints Using FR Fully restrained Rotationally restrained PR Partial restrained Rotationally restrained Page 81 Chapter Seven AS NZS4600 Page 82 The initial position of the loads is at the shear centre If there are no transverse stiffeners leave the stiffener spacing set to zero Tension AS NZS4600 When checking or designing a member for tension you need to specify the correction factor for the distribution of forces at the ends of the member If the members contain significant areas of bolt holes which need to be taken into account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes To enter the properties for tension
125. nto account when determining the cross sectional area of the section you will need to enter the amount of cross sectional area to be deducted to allow for these holes The net area of the section is the gross area minus the combined area of boltholes in the flange and web The reduction in area can be specified by setting the number and diameter of holes in the web or flanges or the member Alternative the user may override this and directly specify the height of holes across the flanges and webs of the cross section These heights are multiplied by the thickness of the section to determine the total reduction in area of the section The initial value for the area of boltholes is zero Chapter Six BS5950 Area Reduction Coefficient BS5950 The reduced tensile capacity of members with eccentric connections is specified by clause 4 6 3 of BS5950 Multiframe Steel Codes does not use this clause but instead approximates the tensile capacity using a similar calculation to that specified by Clause 4 6 1 but which includes an extra factor to account for the reduction in area As such that the tensile capacity is computed in Multiframe Steel Codes using the expression LN DEA in which k represents an area reduction coefficient While this method does not directly represent the calculation of clause 4 6 3 1 it provides a simple method by which to account for the reduced tensile capacity described in this clause For the tensile capacity expression
126. nts To delete a restraint from the member gt Position the cursor within the table on the lateral restraint to be deleted and click the Delete button or if the unbraced length of the member if the be specified directly gt Select the Unbraced Length option gt Enter the unbraced length 1 gt Enter the moment modification factor coefficient Qam to be used in the design of this length of the member And then gt Choose the position of the load from popup menu gt If there are transverse stiffeners on the web type in values for the stiffener spacing s Page 38 Chapter Four AS4100 NZS3404 gt Click OK Generate Lateral Restraints Dialog AS4100 and NZS3404 When the user selects to generate the lateral restraints from the Bending dialog the Generate Lateral Restraints dialog is displayed This dialog enables the user to generate lateral restraints are a specified spacing along the member gt From the Bending dialog click the Generate button x m End Restraints Top Full v Bottom Full DI r Intermediate Restraints Bottom Full y Offset jo 000 m Spacing fi 2 048 m cnc gt Select the type of restraints to be used at the ends of the member gt Select the type of restraints to be used at intermediate points within the member gt Enter the offset length at which the first intermediate restraint will be positioned Leave this field as zero if no offset is sa
127. nts preventing compression buckling about the y y axis It is also possible to enter L and K used in the calculation of torsional buckling resistance at this point Compression Dialog AISC 2005 2010 To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu If the unbraced lengths of the member are to be specified directly then gt Select the Unbrace Length radio button Page 107 Chapter Five LRFD Page 108 Compression Compression 1 000 ky 1 000 kz 1 000 Column Segments Restraints Major Axis Minor Axis Torsion Gg yy some Postion nera nevar esta gt Type in values for Kx Ky and Kz gt Type in values for Lex Ley and Lez gt Click OK The initial values of Lex Ley and Le are the length of the member The default values of K K and K are 1 0 Otherwise if the design for compression is to be performed using column segments gt Select the Column Segments radio button The tabbed control in the dialog will become active The first page in this table lists the location of joints along the members and indicates if they provide restraint against column bucking about either axis of the member Chapter Five LRFD code Compression Compression Unbraced Lengths we Paez w P kz bam Ze Column Segments Restraints Major Axis Minor Axis Torsion ene we yy
128. nu Page 41 Chapter Four AS4100 NZS3404 Page 42 Compression m Major Axis Ke 1 000 m Minor Axis Either gt Click on the icons for the end conditions in each direction or gt Type in values for Kx and Ky gt Type in values for Lex and Ley gt Click OK If you choose a standard end condition the recommended Kx and Ky values will be automatically entered for you Combined Actions AS4100 and NZS3404 The design of a member for combined actions is divided into seven design checks The user can select to check the section capacity and or the member capacity about either the major and or minor axes as well as in biaxial bending When using NZS3404 the combined actions checks are only performed if the member has a significant axial force as defined in the design code No design properties are required when checking or designing members for combined actions using AS4100 or NZS3404 Serviceability AS4100 and NZS3404 Multiframe Steel Codes provides two design checks for the serviceability of a member These design checks are used to check that the deflection of a member about either the major or minor axes does not exceed a specified deflection limit Serviceability Dialog AS4100 and NZS3404 To set the design properties of a member for serviceability gt Select the required members in the Frame window gt Choose Serviceability from the Design menu Chapter Four AS41
129. o determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by Ley KL and Le KI where Ley and Le are the lengths of the member in x and y direction respectively K and K are the two effective length factors for the major and minor axes respectively The initial values of K and K are 1 0 Unbraced Length Eurocode 3 To determine the critical buckling condition of a member it is also necessary to know the spacing of any bracing if any along the member This bracing could be provided by purlins girts or other structural elements which are not modelled in Multiframe Some bracing may only restrain lateral deflection in one direction therefore it is necessary to enter unbraced lengths for both axes of the section Ley corresponding to the spacing of restraints preventing compression buckling about the y y axis and L corresponding to the spacing of restraints preventing compression buckling about the z z axis Chapter Nine User Code Compression Dialog Eurocode 3 To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu I
130. o the principal axes In this case quantities pertaining to the major and minor principle axes are denoted using U and V respectively Design Checks LFRD The types of checks are grouped into the categories Bending Tension Compression Combined and Serviceability The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Bending LFRD The design of a member for bending is divided into four design checks These check the flexural and shear capacity of the member about the major and minor axes Each of these checks may consider one or more limit states depending upon the section and the actions within the member When performing a bending check it is necessary to specify how lateral buckling of the member is resisted Restraint could be provided by other members purlins girts or by other structural elements that are not modelled in Multiframe such as concrete slabs Multiframe Steel Codes provides three methods of specifying how a member is restrained against lateral buckling The user may specify Page 49 Chapter Five LRFD Page 50 That the member is fully restrained against lateral buckling in which case no lateral buckling checks will be performed The location and type of lateral restraints applied to the member in which case Multiframe Steel Codes will appropriately divide the member into a number of spans and consider the capacity of each of these spans in
131. oeff 11 fi 000 gt Type in the area of holes in the web and flanges gt Type ina value for the area reduction coefficient U if required Compression ASD and AlJ Multiframe Steel Codes splits the compressive design of a member into two design checks You may choose to check the slenderness of a member and or its compressive stress When checking or designing members for compression it is necessary to specify the effective length and unbraced length of the member To determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by Lx Kx L and Ly Ky L Page 29 Chapter Three ASD and AL Where L is the length of the member and Kx and Ky are the two effective length factors for the major and minor axes respectively The initial values of Kx and Ky are 1 0 The slenderness is measured as Kx L rx Slenderness Maximum of Ky L ry See also Unbraced Length Compression Dialog ASD and AlJ To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu Compression m Major Axis ky 1 000 m Minor Axis
132. of interaction with the design shear force For the lateral torsion buckling check the design bending moment about the major principle axis is checked to be less than the buckling resistance moment as computed using clause 4 3 6 and annex B 2 For tension checks the design axial tensile force is checked to be less than the tension capacity of the member as computed using clause 4 6 with reference to Annex I 2 The capacity of single angle channel and tee section member is computed using clause 4 6 3 1 if the specified bolt holes indicate that the member is connected via only the flange or web as appropriate Clauses 4 6 3 2 and 4 6 3 3 are not considered The compression section check is a supplemental check not explicitly covered by BS5950 It checks that the design axial compressive force is less than the compressive section capacity that is computed as the product of the gross area of the section and the design strength of the steel i e P A py For major and minor compression buckling checks the design axial compressive force in each column segment is checked to be less than the compressive resistance of each column segment as computed using clause 4 7 5 with specific reference to Annex C 1 and Annex C 2 Clauses 4 7 6 to 4 7 13 are NOT considered Chapter Six BS5950 For all combined action section checks the design axial forces F and F is the maximum tensile and compressive axial forces in the member and the design bending
133. of lateral restraints can be turned on or off via the Symbols Dialog which now contains options for displaying lateral restraints and labelling these restraints The restraints are draw as a short line in the plane of the major axis of the member These lines extend each side of the member for a distance that is roughly the scale of a purlin or girt Lateral restraints are also displayed in the rendered view of the frame in which they are draw to extend from each flange by approximately the size of a purlin The restraints may be labelled using a one or two letters to indicate the type of restraint e g F fixed P partial Note that lateral restraints at the end of a member are draw slightly offset from the node so that restraints at the ends of connected members may be more readily distinguished Unbraced Length le and Bending Coefficient am AS4100 and NZS3404 Instead of specifying the position of lateral restraints it may be preferable to directly set the laterally unbraced length of the member When doing this it is also necessary to specify the bending coefficient Qm as this can no longer be automatically determined by Multiframe Steel Codes The design codes permit a conservative value of a 1 0 to be adopted which is the default value used by Multiframe Steel Codes Web Stiffener Spacing AS4100 and NZS3404 When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web
134. of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Load Height AS4100 and NZS3404 When checking or designing a member for bending you may need to specify the load height position This is used in determining the effective lengths of segments or sub segments along the member Bending Dialog AS4100 and NZS3404 To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Page 37 Chapter Four AS4100 NZS3404 Bending r Lateral Restraints Position Critical IAEA 1 Full Full gt zr el Delete Generate r Stiffener Spacing s gt Load Height 0 000 mm Shear Centre y Cancel Help If the member is fully braced against lateral torsion buckling gt Select the Member is fully laterally restrained option or if the location of lateral bracing along the member is to be specified gt Select the Position of Lateral Restraints option To add new restraint to the member gt Position the cursor with the table and click the Insert button to add a lateral restraint to the member gt Select the position of each restraint gt Select the type of each lateral restraint from the combo provided in each cell or gt Click the Generate button to automatically generate a number of restrai
135. of the optimum sections to their respective members you can use the Use Best Sections command from the Design menu to do this Because changing the sections will change the results of the analysis you will have to re analyse the structure after doing this You may find it useful to wait until you have designed all of the members you wish to optimise before using the Use Best Sections command Optimum Sections Once you have computed an optimum weight section for a member using the Design command the best section will be displayed in the Design Efficiency table in the Result window You can refer to this table to compare the optimal section with the original section If you decide that you want to permanently replace the original section with the best section you should use the Use Best Sections command from the Design menu If you have selected members in the front window you can choose to only update the selected members or you can update the entire frame In any case only members which have been designed will be updated To change sections to the optimum sections designed gt Choose Use Best Sections from the Design menu Best Section A x Change the section types to use the best section You will need to re analyze if you do this Cancel C Change selected members only gt Click the radio button to change just the selected members or the entire frame gt Click OK The sections of the member s chosen will
136. om the Bending dialog the Generate Lateral Restraints dialog is displayed This dialog enables the user to generate lateral restraints are a specified spacing along the member gt From the Bending dialog click the Generate button Page 52 Chapter Five LRFD code Generate Lateral Restraints xj M End Restraints Top Full e Bottom Full y Intermediate Restraints Top Full y Bottom Full y Offset jo 000 m Spacing fi 13 048 m Cancel gt Select the type of restraints to be used at the ends of the member gt Select the type of restraints to be used at intermediate points within the member gt Enter the offset length at which the first intermediate restraint will be positioned Leave this field as zero if no offset is same as the spacing gt Enter the number and size of spacings for the intermediate restraints gt Click OK All lateral restraint applied to the member will now be regenerated and will replace all existing restraints Tension LFRD The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the flange or web of the member and an area reduction factor to account for the distribution of forces at the ends of a member In addition to checking the tensile capacity of the member a design constraint
137. ompared to find the appropriate equation to calculate M Equ A F1 1 to 4 Each M value for the failure modes are then compared with the lowest value governing Flange local bucking will only be considered for sections with non compact flanges Similarly web local buckling will only be considered for sections with non compact webs The design for shear is carried out in accordance with clause F2 using the provisions of Appendix F2 2 when a stiffener spacing is specified For plate girders with slender web elements the provisions of Appendix G3 will be utilised instead No calculations are conducted using Chapters K or J For the biaxial bending check interaction equations of Appendix H1 are evaluated ignoring the axial force term The expressions are computed using the maximum actions in the members If this check fails the user For the combined action check for flexure and compression the member is checked in accordance with clause H1 1 using the design moments about the major and minor axes A more refined LRFD SAM Clauses Checked Load and Resistance Factor Design Specification for Single Angle Members American Institute of Steel Construction November 10 2000 The design checking procedure is the same as described above for LRFD except that The section is classified using the limits set out in clause 4 of LRFD SAM The same clause is used to compute the slenderness reduction factors and effective area of the section C
138. on 5 1 4 For major and minor shear the shear stress is checked to be less than the allowable fs found from equation 5 2 The shear stress is computed using a shear area as shown above For major and minor deflection due to bending the maximum deflection is checked to be less than L 300 in accordance with clause 10 1 No specific check is made for cantilevered members For tension checks the tensile stress is checked to be less than the allowable ft as computed using equation 5 1 For slenderness checks the slenderness ratio is computed as the maximum of KxL rx and KyL ry This is checked to be less than the allowable slenderness ratio of 200 for vertical members or 250 for non vertical members in accordance with clause 11 2 A vertical member is assumed to be one which is within 100mm of vertical For compression checks the compressive stress is checked to be less than the allowable fc as computed in equation 5 3 or 5 4 For combined compression and bending checks the stresses are checked to be low enough to satisfy equations 6 1 and 6 2 Page 33 Chapter Three ASD and AL Page 34 For combined tension and bending checks the stresses are checked to be low enough to satisfy equations 6 3 and 6 4 The area of bolt holes as specified in the Bolt Holes dialog is deducted from the gross section area to calculate the net section area For sway checks the horizontal deflection of the highest part of the member is checked to be
139. on checks are to be considered the member is first checked to determine if it has a significant axial force in accordance with clause 8 1 4 For members without a significant axial force all combined action checks are skipped The member is checked to see if the use of alternative design criteria is acceptable This check is conducted to clause 8 1 5 but does not consider the plate slenderness limits of clause 8 1 5 b i Hence alternative design provisions will only be used if the cross section is compact For major and minor combined section checks the design bending moment is checked to be less than the nominal section moment design capacity reduced by axial force compression or tension as computed using clause 8 3 2 and 8 3 3 For combined biaxial section checks the design bending moments are checked to satisfy clause 8 3 4 Page 47 Chapter Four AS4100 NZS3404 Page 48 For major and minor combined in plane member checks the design bending moment is checked to be less than the nominal in plane member moment design capacity as computed using clause 8 4 2 Clause 8 4 3 is NOT considered For combined out of plane member checks the design bending moment about the major axis is checked to be less than the nominal in plane member moment design capacity as computed using clause 8 4 4 For combined biaxial member checks the design bending moments are checked to satisfy clause 8 4 5 Clause 8 4 6 is NOT considered For
140. oose which load case is displayed by choosing the appropriate item from the bottom of the Case menu You can also view the Design Efficiency table in this window Plot Window This window is used for viewing diagrams of the results of the analysis carried out on the frame The results for one load case at a time may be viewed in this window You can choose which load case is displayed by choosing the appropriate item from the bottom of the Case menu You can also view a colour plot of design efficiency in this window Page 131 Chapter Ten Steel Designer Reference Page 132 Report Window This window is used for viewing a summary report of the design checks carried out on the frame You can turn on or off the option to create a summary report when you use the Check or Design commands Menus When the Multiframe Steel Codes module is active some extra menu items are displayed in the Multiframe menus In addition the function of some of the Multiframe menu items change in order to support the Report Window The menu items with modified behaviour and the additional menu items are as follows e Group Menu e Design Menu e Code Submenu e Display Menu e Efficiency Submenu e Help Menu Group Menu The Group menu provides commands for organising the members in the structural model into groups or assemblies The entries in this menu relevant to design are list below Create Design Member Group the selected members together to fo
141. orm in the Design Details tab of the Data window Although most of the design variables are pre set to the most commonly used values you will probably want to enter the design information for at least some of the members in the frame that you wish to check You set design variables by selecting the members you wish to change and then choosing the appropriate command from the Design menu There are a number of design variables which are used when doing checking to the code A summary of all of the design variables is as follows Name Value F F Effective length factor for buckling about the section s 1 0 strong axis m y u Kx Ky Lex Ley Unbraced length for preventing column buckling about member s the section s strong axis length Unbraced length for preventing column buckling about member s the section s weak axis length Lateral The lateral restraints acting on the member Each end of restraints the member is fully restrained at both flanges Effective length factor for buckling about the section s weak axis Length of stiffeners Assume that all stiffeners have the 0 0 Ge no same length regardless of whether they are web stiffeners stiffeners or flange stiffeners Page 89 Chapter Eight AISI Edge distance between the first stiffener and the element 0 0 ie no edge Assume that all stiffeners on a web or flange are stiffeners symmetric to the centre line of the element The distance between the fir
142. r Five LRFD code The plate elements of the section will be classified as Compact Non Compact Slender as per the requirements of clause B5 1 and Table B5 1 These elements may also be classified as Very Slender 1f they exceed the limitations set out in Table A F1 1 If the moments in the member are less than one ten thousandth of the yield moments the section is considered to be in pure compression and will be classified accordingly If an element of the section is found to be slender the stiffness reduction factors Q Q and Q will be determined as set out in Appendix B For tension checks the capacity of the member is determined in accordance with section D1 For compression checks the capacity of the member is firstly computed for the limit states of flexural buckling about the major and minor axis is accordance with clause E2 The capacity of the member for the limit state of flexural torsional buckling is then computed using clauses E3 and Appendix E The compressive capacity of the member is regarded as being the minimum capacity determined for these three limit states For bending checks the provisions of Appendix Fl are used For each of the failure modes yielding flange local buckling web local buckling and lateral torsional buckling A Ap and A values are calculated The values are based upon the section shape and the axis of bending and are derived from Table A F1 1 After the various values have been calculated they are then c
143. r a segment with an unrestrained end the critical flange is the tension flange For each restraint on the member the user must specify the type of restraint As this depends upon which flange is the critical flange the user must specify the type of lateral restraint that would be present at a section if 1 The top flange were the critical flange and ii The bottom flange was the critical flange Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange The different restraints acting on the member can be specified as Restraint Type Abbreviation Fully restrained Partially restrained Laterally Restrained Unrestrained Continuous restraint Ce Ei PG Fully or partially restrained sections may also be specified as lateral rotational restraints using Restraint Type Abbreviation Fully restrained and Rotationally restrained FR Partial restrained and Rotationally restrained PR The initial position of the loads is at the shear centre If there are no transverse stiffeners leave the stiffener spacing set to zero Chapter Four AS4100 NZS3404 The location and type of lateral restraints can be displayed in the Frame and Plot windows The display
144. r checked The design checks are grouped into the categories Bending Tension Compression Combined and Seismic However not all codes have checks in each category and the design checks listed within each category vary according to the design code performed when a member is designed or checked Design Members A design member is a single member or a group of co linear members that are to be considered as a single member for the purposes of design In this manual the term member often refers to a design member when used in the context of design Bending Checks Bending checks are usually used on members which resist the applied loads by flexural and shear actions Typically the horizontal members in a frame will support the live and gravity loads in this way A member may be subject to flexure and shear in either the major or minor axis directions or both depending the orientation of the section and the direction of the loading Tension Checks Tension checks are performed on members that are subject to axial tension This would include members such as bracing and members in trusses which are under tension Chapter One Introduction Compression Checks Compression checks are used on members that support axial compression Columns and bracing in frames and compression members in trusses are some of the types of members that are likely to be checked using this option Some codes may also include a check on the slenderness of a member
145. r group of members gt Select the required members in the Frame window gt Choose Member Material from the Frame menu Page 15 Chapter Two Using Steel Designer Member Material Group Material ESSE AS3679 250 Steel AS3678 AS3679 300 Steel AS1163 AS3679 350 Steel AS 1397 AS3679 400 Steel AS1594 AS3679 300PLUS Steel AS51595 Concrete AS3600 Aluminium User Materials 1 User Materials 2 United States sections library shown gt Choose the material from the list gt Click OK Note that if the elastic properties of the new material differ from the original material then you will need to re analyse the structure using the Analyse command from the Case menu Important Using Materials When a material is assigned to a member Multiframe Steel Codes will try to match the material to one of the standard steel grades supported by the current design code In this way the design checks performed by Multiframe Steel Codes are able to take advantage of clauses that refer to specific steel grades e g yield strengths that vary with thickness All design properties including ultimate and yield strengths will be obtained from values specified within the design code If a material is not matched to a standard steel grade then the values of the yield and ultimate strength will be obtained from the material instead of from the design code Furthermore clauses that refer to specific design
146. ral restraints can be turned on or off via the Symbols Dialog which now contains options for displaying lateral restraints and labelling these restraints The restraints are draw as a short line in the plane of the major axis of the member These lines extend each side of the member for a distance that is roughly the scale of a purlin or girt Lateral restraints are also displayed in the rendered view of the frame in which they are draw to extend from each flange by approximately the size of a purlin The restraints may be labelled using a one or two letters to indicate the type of restraint Lateral are labelled using the following notation U Unrestrained L Lateral restraint LR Lateral restraint with full restraint against rotation on plan LP Lateral restraint with partial restraint against rotation on plan Note that lateral restraints at the end of a member are draw slightly offset from the node so that restraints at the ends of connected members may be more readily distinguished Unbraced Length L and Bending Coefficient m 1 BS5950 Instead of specifying the position of lateral restraints it may be preferable to directly set the laterally unbraced length of the member When doing this it is also necessary to specify the bending coefficient m r as this can no longer be automatically determined by Multiframe Steel Codes The design codes permit a conservative value of mur 1 0 to be adopted which is the default value
147. rame Type Some design calculations depend on whether the frame is free to deflect laterally sway or is restrained by internal or external bracing to prevent side sway braced A sway frame develops all of its horizontal stiffness due to the flexural actions of the columns in the structure In contrast the bracing in a braced frame absorbs the horizontal forces and horizontal deflections of the columns are reduced to a minimum To set the type of frame gt Choose Frame Type from the Design menu Frame Type Mm x Frame Type z C Braced Frame Cancel gt Click on type of the frame gt Click OK The initial setting for the frame type is a sway frame Setting Allowable Stresses Some steel design codes permit you to increase the allowable stresses by a set amount usually 33 or 50 for load cases that only involve temporary loading Multiframe Steel Codes allows you to utilize this option by using the Allowable Stresses option from the Design menu This allows you to enter a factor for the allowable stress increase for each load case The initial value of the allowable stress increase factor is 1 0 for all load cases If for example you wanted the stresses for a load case to be allowed to increase by 33 you would enter a value of 1 33 Page 19 Chapter Two Using Steel Designer Setting Acceptance Ratio Some of the design codes within Multiframe Steel Codes allow the user to modify the value of t
148. rawn as a short line in the plane of the major axis of the member These lines extend each side of the member for a distance that is roughly the scale of a purlin or girt Lateral restraints are also displayed in the rendered view of the frame in which they are draw to extend from each flange by approximately the size of a purlin The restraints may be labelled using a one or two letters to indicate the type of restraint e g F fixed P partial L lateral Note that lateral restraints at the end of a member are draw slightly offset from the node so that restraints at the ends of connected members may be more readily distinguished Unbraced Length L AISC 2005 2010 Instead of specifying the position of lateral restraints it may be preferable to directly set the laterally unbraced length of the member L Web Stiffener Spacing AISC 2005 2010 When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Bending Dialog AISC 2005 2010 To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Page 103 Chapter Five LRFD Bending Lateral Restraints Lb 5 657 Stiffner Spacing a 0 000 mm O Unbraced L
149. rm a multi member design member Remove Design Member Delete or split the selected members from multi member design member s Design Menu The Design menu provides commands for checking and optimising the members in your structure Code See Code Submenu Check Check the selected members in the Frame window for their compliance with the current code You may use the Check dialog to choose which design calculations should be carried out and which load cases should be checked Design Select the lightest weight sections for the selected members in the Frame window that will satisfy the design criteria You may use the Design dialog to choose which design calculations should be carried out and which load cases should be examined Chapter Ten Steel Designer Reference Bending Specify the design parameters controlling bending checks Enter the unbraced lengths for the selected members in the Frame window and specify any web stiffener spacing Tension Specify the design parameters used for tension checks Specify the area of any boltholes which must be subtracted from the cross sectional area of the section when doing design calculations Compression Specify the design parameters controlling compression checks Allows you to select the effective lengths and the unbraced lengths for the selected members in the Frame window Combined Specify the design parameters controlling combined bending and compression chec
150. rresponding to the spacing of restraints preventing buckling about the y y axis The initial values of Lbx and Lby are the length of the member Page 27 Chapter Three ASD and AL Page 28 Bending Coefficient ASD The ASD code requires a bending coefficient Cb that is either calculated by the program according to the rules in the code or may be specified by the user If you leave Cb unchanged Multiframe Steel Codes will select a value for you which will be displayed in Italics in the Design Details table in the Data window This value is most commonly 1 0 If you type in a value Multiframe Steel Codes will always use this value and display it in non italic i e standard text in the Design Details table Web Stiffener Spacing ASD and AlJ When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Bending Dialog ASD and AlJ To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Bending Major Unbraced Length Lbg Minor Unbraced Length Lby Bending Coefficient ehm mmm Web Stiffener Spacing a gt Type in values for Lbx and Lby gt If necessary enter a value for the bending coefficient Cb gt
151. s Australian Institute of Steel Construction Sydney 1994 2nd Edition Design Capacity Tables for Structural Steel Hollow Sections Australian Institute of Steel Construction Sydney 1992 1st Edition Page 140 Index A About this manual 1 Acceptance Ratio 20 AU 33 134 Allowable Stresses 19 20 134 area reduction coefficient 29 AS 4100 134 135 AS NZS 4600 86 AS NZS4600 77 89 AS1250 to User 134 AS4600 77 89 ASD 134 ASD AIJ 137 B Bending 13 27 35 62 79 91 133 Bending Major Member 136 Bending Major Section 136 Bending Major Shear 136 Bending Minor Section 136 Bending Minor Shear 136 Bending Checks 4 bending coefficient 28 Bending Compression 138 Bending Tension 138 bolt holes 29 BS5 950 134 C Capacity Factors 134 Check 132 Checking a Frame 20 CISC 134 Code Checks 86 98 Code Menu 134 Column Restraints 69 Combined 133 Combined Biaxial Member 137 Combined Biaxial Section 137 Combined Major In Plane 137 Combined Major Section 136 Combined Minor In Plane 137 Combined Minor Section 136 Combined Out of plane 137 Combined Actions 13 31 42 71 84 96 Combined Checks 5 compression 30 41 69 107 121 Compression 13 29 41 68 83 95 133 138 Compression Major Member 136 Compression Minor Member 136 Index Compression Section 136 Compression Checks 5 Constraints 133 Coordinate Systems 9 Crea
152. s of clause 4 6 3 is can be shown that minimum values of k are Clause 4 6 3 1 bolted connections P p A 0 5a2 gt kt 0 5 welded connections P py A 0 3a2 gt kt 0 7 Clause 4 6 3 2 bolted connections P py A 0 25a2 gt kt 0 75 welded connections P py A 0 15a2 gt kt 0 85 while less conservative values of k based upon the gross area of the connected element taken as half the gross are of the section are as follows Clause 4 6 3 1 bolted connections P p A 0 5a2 gt kt 0 75 welded connections P py A 0 3a2 gt kt 0 85 Clause 4 6 3 2 bolted connections P p A 0 25a2 gt kt 0 875 welded connections P py A 0 15a2 gt kt 0 925 Tension Dialog BS5950 To enter the properties for tension gt Select the required members in the Frame window gt Choose Tension from the Design menu Page 67 Chapter Six BS5950 Page 68 x Tension m Holes Web Flange No re fo Diameter 0 000 0 000 Mm Total Height 0 000 0 000 mm Area Reduction Coefficient Kt 1 0 v gt Type in the number and diameter of holes in the webs and flanges and the total height of holes will be computed automatically or gt Type the total height of holes in the webs and flanges directly gt Choose or enter a value for the Area Reduction Coefficient kt if required gt Click OK Compression BS5950 Multiframe Steel Codes spl
153. s that the dimensions of the resulting calculations will be consistent All stresses and strengths have units as set for the Stresses option in the Units dialog The four different parts of the User code correspond to the four groups of checks available when using the Check and Design commands The bending checks can be used to check bending stresses shear stresses and deflections These formulas will be applied to both the major and minor axis beam calculations Bending 51 IV Bending Stress RS kii IV Bending Stress lt 2 4 ksi IV ShearStess lt f04Fy be MV Shear Siess BC ki aa M Deflection lt L300 in M Deflection lt M h Tension BE ES d et M Tensile Stress lt Ss si IV Tensile Stress lt 0 5 Fu ksi Cancel Tensile Stress lt 36 ksi Eca The compression checks will be used for the Slenderness and Compression check options when using the Check and Design commands Compression TT E Slendemess kL lt BI lt Cis s eren IV Compressive Stress lt 25 ksi S Cancel IV Compressive Stress lt EP ZEAZ3KeLiyY2 ksi Chapter Nine User Code The combined checks will be used for the Combined check options when using the Check and Design commands The combined stress checks check the user formula against a combined stress ratio CSR of 1 0 Combined BBE IV Compression and Bending fe 0 6 F y fbx 0 6 Fy fby 0 6 Fy lt 1 0 IV Tension and Bending Jft 0 6 F y fbx 0 6 Fy
154. s will work through the selected members checking the stresses for the load cases you have chosen for compliance with the design rules you specified The result of the check for the current load case will be displayed in the Design Efficiency table in the Result window Each column in this table shows the member s strength as a percentage of the allowable strength according to the code For example an efficiency of 95 means that the member is being stressed to 95 of its allowable value An efficiency greater than 100 indicates that the member is being stressed to a higher level than that permitted by the code The Overall column shows the highest value of all of the design checks for the member for the current load case The subsequent columns show the result for the individual checks which have been carried out You can display the results for different load cases by choosing the appropriate item from the Case menu The check will be much slower if you choose to have a summary report generated however the report will contain detailed information about all of the design checks carried out You will probably find it best to do an overall check on the areas of interest without the report on and then check a few key members using the full report option Page 21 Chapter Two Using Steel Designer Displaying Efficiency As well as displaying the table of member efficiency in the Result window you can view these values graphically in the Plot
155. ser to generate lateral restraints are a specified spacing along the member gt From the Bending dialog click the Generate button Generate Lateral Restraints End Restraints Top S Bottom Lateral y Torsion Unestained m Intermediate Restraints Top Lateral y Bottom Lateral Torsion Unrestrained ba Offset Spacing e s Cancel Page 118 Chapter Nine User Code gt Select the type of restraints to be used at the ends of the member gt Select the type of restraints to be used at intermediate points within the member gt Enter the offset length at which the first intermediate restraint will be positioned Leave this field as zero if no offset is same as the spacing gt Enter the number and size of spacing for the intermediate restraints gt Click OK All lateral restraint applied to the member will now be regenerated and will replace all existing restraints Tension Eurocode 3 The capacity of a member to resist tensile forces is implemented as a single design check A number of modification factors may be entered to change the section properties used for checking tension This includes the area of holes in the flange or web of the member and a shear lag factor to account for the distribution of forces at the ends of a member In addition to checking the tensile capacity of the member a design constraint will be applied to the member enforcing the slenderness of th
156. sign members and using the commands under the Design menu or it can be entered in tabular form in the Data window The actual design parameters that can be changed by the user will vary according to the current design code A list of design variables and their default values are described in subsequent chapters in this manual Although most of the design variables are pre set to the most commonly used values you will probably want to enter the design information for at least some of the members in the frame that you wish to check You set design variables by selecting the members you wish to change and then choosing the appropriate command from the Design menu It is not necessary to enter the design data for all of the design checks Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing The design properties are grouped according the categories described above and the items in the Design menu reflect these groupings The dialogs displayed by each of these commands will vary according the current design code 12 Chapter Two Using Steel Designer Bending When performing a bending check you may need to specify a number of properties relating to the unbraced length location and type of lateral restraints and the stiffener spacing on the member Tension Tension checks usually require t
157. sition of each restraint Page 64 Chapter Six BS5950 gt Select the type of each lateral restraint from the combo provided in each cell or gt Click the Generate button to automatically generate a number of restraints To delete a restraint from the member gt Position the cursor within the table on the lateral restraint to be deleted and click the Delete button And then to display the list so segment defined by the restraints gt Click on the Segments tab Lateral Restraints Segments Load een Mm contin 1 2 505 Normal eee a E gt For each segment choose the position of the load from popup menu or if the unbraced length of the member if the be specified directly gt Select the Unbraced Length option gt Enter the unbraced length le gt Enter the moment modification factor coefficient m r to be used in the design of this length of the member gt If there are transverse stiffeners on the web type in values for the stiffener spacing s gt Click OK Generate Lateral Restraints Dialog BS5950 When the user selects to generate the lateral restraints from the Bending dialog the Generate Lateral Restraints dialog is displayed This dialog enables the user to generate lateral restraints at a specified spacing along the member gt From the Bending dialog click the Generate button The Generate Lateral Restrains dialog will appear allowing you to specify the restraints to
158. splay the Minor Bending Minor Section Bending efficiency as a colour on each member for the current load case in the Plot window Bending Minor Shear Display the Minor Shear Bending Minor Shear efficiency as a colour on each member for the current load case in the Plot window Tension Display the Tension efficiency as a colour on each member for the current load case in the Plot window Compression Section Display the Compression Section Compression efficiency as a colour on each member for the current load case in the Plot window Compression Major Member Display the Major Member Compression efficiency as a colour on each member for the current load case in the Plot window Compression Minor Member Display the Minor Member Compression efficiency as a colour on each member for the current load case in the Plot window Combined Major Section Display the Combined Major Section efficiency as a colour on each member for the current load case in the Plot window Combined Minor Section Display the Combined Minor Section efficiency as a colour on each member for the current load case in the Plot window Chapter Ten Steel Designer Reference Combined Major In Plane Display the Combined Major In Plane efficiency as a colour on each member for the current load case in the Plot window Combined Minor In Plane Display the Combined Minor In Plane efficiency as a colour on each member
159. st and the second stiffener 0 0 ie less Assume that all stiffeners on a web or flange are than 3 symmetric to the centre line of the element stiffeners No of Number of stiffeners This is either the total number of 0 i e no stiffeners stiffeners on the web s or the total number of stiffeners stiffeners on the flange s eg for a C section with 8 stiffeners on flanges so each flange has 8 2 4 stiffeners However for a back to back C section with 8 stiffeners each flange has 8 4 2 stiffeners The number of holes in the flanges of the section Diameter Diameter of holes in the flanges of the section of Flange Holes Total Total height of any bolt holes in the flanges of the section Height of This value may be input directly or computed Flange automatically when the number and diameter of flange Holes holes are specified The number of holes in the webs of the section Diameter Diameter of holes in the webs of the section of Web Holes Total Total height of any bolt holes in the webs of the section Height of This value may be input directly or computed Web automatically when the number and diameter of flange Holes holes are specified 10 Depth when using the Design command initial section Depth when using the Design command initial section Width when using the Design command initial section Min The minimum width of section which may be chosen width of the Width when using the Design command in
160. summary of all of the design variables is as follows Name Value F F Effective length factor for buckling about the section s 1 0 weak axis Unbraced length for preventing column buckling about member s the section s strong axis length Unbraced length for preventing column buckling about member s the section s weak axis length y u Kx Ky Lex Ley Effective length factor for buckling about the section s 1 0 strong axis Page 77 Chapter Seven AS NZS4600 Lateral The lateral restraints acting on the member Each end of restraints the member is fully restrained at both flanges Length of stiffeners Assume that all stiffeners has the 0 0 Ge no same length regardless of web stiffeners or flange stiffeners stiffeners Edge distance between the first stiffener and the element 0 0 ie no edge Assume that all stiffeners on a web or flange are stiffeners symmetric to the centre line of the element The distance between the first and the second stiffener 0 0 ie less Assume that all stiffeners on a web or flange are than 3 symmetric to the centre line of the element stiffeners No of Number of stiffeners This is either the total amount of 0 i e no stiffeners stiffeners on web s or the total amount of stiffeners on stiffeners flange s eg for a C section with 8 stiffeners on flanges so each flange has 8 2 4 stiffeners However for a back to back section with 8 stiffeners each flange has 8 4 2 st
161. te Design Member 132 critical buckling load 83 95 107 120 D Data 135 Data Window 6 131 Design 132 Design Checking Procedure 86 98 Design Constraints 27 Design Constraints 18 Design Details 133 135 Design Members 4 Design Members 7 Design Members 12 Design Menu 132 Design Properties 13 84 96 Designing a Frame 23 Display Menu 135 E Edit User Code 135 effective length 83 95 107 120 factor 83 95 107 120 Efficiency 22 135 Efficiency Menu 135 Enabling Steel Designer 4 Eurocode 134 F Finding Design Values 25 Frame Type 19 133 Frame Window 6 131 Fu 15 17 Fy 15 17 G Governing Load Cases 22 Group Menu 132 H Help Menu 138 K Kx 30 42 70 108 121 Ky 30 42 70 108 121 Page 141 Index L Lbx 27 Lby 27 Lex 41 Load Window 131 LRFD 135 M Major Bending 137 Major Deflection 138 Member Efficiency 135 Menus 132 Minor Bending 138 Minor Deflection 138 Minor Shear 137 138 N NZS 3404 134 O Optimization 25 Optimum Sections 24 Overall 135 137 P Plot Window 6 131 Primary Deflection 137 Printing 25 R Remove Design Member 132 Report Window 7 132 restraint 83 95 107 120 Result Window 6 131 Results 135 Page 142 S Saving the report 26 Saving your Work 26 Secondary Deflection 137 Section Constraints 18 Section Type 15 Seismic 133 Seismic 35 43 Seismic Checks 5 S
162. the member and the design bending moments Mx and My are the maximum bending moments in the member For major and minor combined section checks the design bending moment is checked to be less than the nominal section moment design capacity reduced by axial force compression or tension as computed using clause CS References AISI You may find the following books useful to refer to if you need information on the methods used to check members in Multiframe Steel Codes e Cold formed Steel Design Wei Wen Yu John Wiley amp Sons Inc New York 2000 3rd Edition e Design of Cold formed Steel Structures to the AISI Specification Gregory J Handcock Thomas M Murray and Duane S Ellifritt Marcel Dekker Inc New York 2001 Chapter Eight AISI e Design of Cold formed Steel Members J Rhodes Department of Mechanical Engineering University of Strathclyde Glasgow UK 1991 e Multiframe Steel Codess Handbook B Gorenc R Tinyou and A Syam UNSW Press Sydney 1996 6th Edition e The Behaviour and Design of Steel Structures N S Trahair and M A Bradford Chapman and Hall London 1988 Page 99 Chapter Five LRFD code Chapter 9 AISC 2005 2010 This chapter describes the implementation of the AISC Specification for Structural Steel Buildings within Multiframe Steel Codes It provides a step by step description of how to modify the design properties used by the code The AISC 2005 is a single unified structur
163. tical axis of the member For design to AISC 2005 it is assumed that the X axis is the major axis and Y is the minor axis Page 101 Chapter Five LRFD Page 102 Design Checks AISC 2005 2010 The types of checks are grouped into the categories Bending Tension Compression Combined and Serviceability The user may specify which of these checks are performed when a member is designed or checked using Multiframe Steel Codes Bending AISC 2005 2010 The design of a member for bending is divided into four design checks These check the flexural and shear capacity of the member about the major and minor axes Each of these checks may consider one or more limit states depending upon the section and the actions within the member When performing a bending check it is necessary to specify how lateral buckling of the member is resisted Restraint could be provided by other members purlins girts or by other structural elements that are not modelled in Multiframe such as concrete slabs Multiframe Steel Codes provides three methods of specifying how a member is restrained against lateral buckling The user may specify That the member is fully restrained against lateral buckling in which case no lateral buckling checks will be performed The location and type of lateral restraints applied to the member in which case Multiframe Steel Codes will appropriately divide the member into a number of spans and consider the capacity of each of these
164. ultiframe Steel Codes will appropriately divide the member into a number of spans and consider the capacity of each of these spans in determining the capacity of the member Alternatively the laterally unbraced length Ly can be specified You may need to specify a number of properties relating to the location and type of lateral restraints and the stiffener spacing along the member Lateral Restraints Eurocode 3 If the spacing of lateral restraints along the member is specified Multiframe Steel Codes uses this information to break the member up into a number of spans in order to determine lateral torsion buckling capacity of each span In Multiframe Steel Codes these spans are known as segments Each lateral restraint specified by the user is assumed to provide bracing against lateral displacement of the critical flange and or prevent twist of the cross section At any cross section the critical flange is the flange that in the absence of any restraint at that cross section would deflect the furthest during buckling of the member In most members the critical flange will be the compression flange However for a cantilevered member the critical flange is the tension flange For each restraint located along a member the user must specify the type of restraint As this depends upon which flange is the critical flange which is not know a priori the user must specify the type of lateral restraint that would be present at a section if e
165. unch the table of contents of the Multiframe Steel Codes help file Page 139 References References You may find the following books useful to refer to if you need information on the methods used to check members in Multiframe Steel Codes Manual of Steel Construction Allowable Stress Design American Institute of Steel Construction New York 1989 9th Edition Manual of Steel Construction Load amp Resistance Factor Design American Institute of Steel Construction New York 1986 1st Edition Steel Buildings Analysis and Design S W Crawley amp R M Dillon John Wiley amp Sons New York 1984 3rd Edition Structural Steel Design LRFD Fundamentals J C Smith John Wiley amp Sons New York 1988 1st Edition The Behaviour and Design of Steel Structures N S Trahair and M A Bradford Chapman and Hall London 1988 Australian Standard AS4100 1990 Steel Structures Standards Australia Australian New Zealand Standard AS NZS 4600 2005 Cold formed Steel Structures Standards Australian and New Zealand Design of Cold formed Steel Structures to Australian New Zealand Standard AS NZS 4600 1996 G J Handcock Australian Institute of Steel Construction Sydney 1998 3rd Edition New Zealand Standard NZS 3404 1997 Steel Structures Standards New Zealand Multiframe Steel Codess Handbook B Gorenc R Tinyou and A Syam UNSW Press Sydney 1996 6th Edition Design Capacity Tables for Structural Steel Volume 1 Open Section
166. ut the x x axis and Lcy corresponding to the spacing of restraints preventing compression buckling about the y y axis To determine the critical buckling load for a member it is necessary to enter an effective length to indicate the type of restraint on the ends of the member The effective length is given by an effective length factor multiplied by the unbraced length of the member The effective length may be different for buckling in the major and minor axis directions The effective lengths are given by Lx Kx Lex Ly Ky Lcy and Lz Kz Lez Where Lcx and Ley is the unbraced length of the member and Kx Ky the two effective length factors for the major and minor axes respectively Lcz is the unbraced length and Kz is the effective length factor of the member for torsional buckling The initial values of Kx Ky and Kz are 1 0 and the initial values of Lcx Lcy and Lcz are the length of the member In addition to checking the compressive capacity of the member a design constraint will be applied to the member enforcing the slenderness of the member to be less than 200 Compression Dialog LFRD To set the properties for compression gt Select the required members in the Frame window gt Choose Compression from the Design menu x Compression m Major Axis ky 1 000 m Minor Axis Ky fi 000 r Torsion Ke 1 000 Cancel Either Page 55 Chapter Five LRFD Page 56
167. via the Symbols Dialog which contains options for displaying and labelling lateral restraints The restraints are drawn as a short line in the plane of the major axis of the member These lines extend each side of the member for a distance that is roughly the scale of a purlin or girt Lateral restraints are also displayed in the rendered view of the frame in which they are draw to extend from each flange by approximately the size of a purlin The restraints may be labelled using a one or two letters to indicate the type of restraint e g F fixed P partial L lateral Note that lateral restraints at the end of a member are draw slightly offset from the node so that restraints at the ends of connected members may be more readily distinguished Unbraced Length L Eurocode 3 Instead of specifying the position of lateral restraints it may be preferable to directly set the laterally unbraced length of the member L Web Stiffener Spacing Eurocode 3 When checking or designing a member for bending you may need to specify the spacing of any stiffeners along the web of the member This affects the member s susceptibility to buckling due to bending If there are no transverse stiffeners you should leave the stiffener spacing set to zero Bending Dialog Eurocode 3 To set the properties for bending gt Select the required members in the Frame window gt Choose Bending from the Design menu Bending Lateral Restraints M
168. w AISI North American Specification for the Design of Cold formed Steel Structural Members AISI Standards 2001 Edition Clauses used are C2 CS Design Checking Procedure The design checking procedure is as follows The design actions are calculated through the first order analyses and a second order analysis should be used for sway frames For major and minor bending section checks the design bending moment is checked to be less than the nominal section moment design capacity as found using clause C3 For bending member checks the design bending moment about the major principle axis is checked to be less than the nominal member moment design capacity as found using clause C3 1 For major and minor shear checks the design shear force is checked to be less than the nominal shear capacity found from section C3 2 For tension checks the design axial tension force is checked to be less than the nominal section design capacity in tension as computed using clause C2 For compression section checks the design axial compressive force is checked to be less than the nominal section design capacity in compression as computed using clause C4 For major and minor compression member checks the design axial compressive force is checked to be less than the nominal member design capacity in compression as computed using clause C4 1 C4 6 For all combined action section checks the design axial force P is the maximum axial force in
169. ween the colours and the level of efficiency Members that are more highly loaded stressed or deflected than the level allowed by the code are shown in red You can use the Symbols command from the Display menu to turn on the display of Plot values When this option is on the values of the efficiency will also be displayed on each member that has been checked Report Window This window is used to create a progressive summary of the design that has been carried out Steel Design Report Checking CAndrew Multifr ame Cant 1 mfd to ASD code Monday August 08 1997 11 31 AM Checking member 1 Group M Section M12x10 Load Case Load Case 1 Fy 36 ksi On gross area Fi 0 6 Fy 0 6 36 21 6 ksi On net area Fi 0 5 Fu 0 5 59 29 ksi hit 11 61 0 149 77 919 gt 380A Fy 380 4 36 63 333 0190 wFY 1 9011 1 61 0 149 5 34 36 0 939 Fvw Fy Cw2 89 36 0 939 2 89 11 699 ksi Cco l 2 2 EFY U2 R 2 29000 996 36 126 101 Kirmanci KyUr maw 1 196 851 4 57 1 196 85110 576 341 754 Fant 2 x 2 EN23 KLity 2 1 2 x 2 29000 996 23 341 754 2 1 279 ksi bit 1 625 0 18 9 028 S 65N Fy 65 N 36 10 833 Section is Compact Major Axis Le min 76 DFN 20000 WAPFY min 76 3 25 1 36 20000 11 97 0 585 36 min 3 431 2 263 2 263 Lb gt Le Fb 0 6 Fy 0 6 36 21 6 ksi i Cbh 1 75 1 05 M1 M2 0 3 11 2 2 1 751 D r 368 281 0 3 0 368 781 2 1 75 Fb 170x1 0 3 CbM liT 2 1 70x1 0 3 1 75 196 851100 768 2 4 531 ksi Fb 1210 3 Ch 1 d AN 1 2x1 0
170. window To view the member efficiency gt Choose the required item from the Efficiency sub menu under the Display menu 10 x Efficiency Overall 55 Acceptance Ratio 5 Overall Efficiency The members will be drawn in the Plot window with a colour code indicating the efficiencies of the members The scale shown in the legend may be used to determine the relative values of the colours Members which exceed the allowable capacity will have an efficiency greater than acceptance ratio for the member typically 100 and will be drawn in orange or red If you turn on the display of Plot Values in the Symbols dialog under the Display menu the values of the efficiencies will be displayed on the members Values and colours will only be drawn for members which have been checked You can also use the clipping and masking commands to restrict which members have their efficiency values displayed Governing Load Cases The governing load case associated with the overall design of a member is recorded when designing or checking a member The governing load case associated with each member is displayed in the Efficiency table in the Result Window The load cases governing the design of each of the individual design checks are also recorded when designing or checking a member The governing load case for a specific design check can be displayed in two ways as a cell tool tip in the Efficiency table or as a member tool tip i
171. y restrained at both flanges buckling length Po Spacing of web stiffeners This is the spacing of any stiffeners along the web of a beam stiffeners SU Holes ESO a Flange Holes owe E GE Holes flanges of the section See CL Holes of the section PA o Holes Web Holes Longitudinal spacing of staggered holes in the webs E Holes of the section Gage of Web Transverse spacing of staggered holes in the webs Holes of the section Shear Lag Factor for the distribution of forces Fabrication The method by which the section was Hot Rolled manufactured This describes the residual stresses in the section It is not necessary to enter all of the above information for all members Usually you will want to check some members for bending others for compression and so on The items under the Design menu help you enter just the required information depending on what type of check you are doing Code Clauses Checked AISC 2005 2010 When carrying out code checks Multiframe Steel Codes uses the following clauses of the applicable codes to check your structure No other checks are performed unless they are specifically listed below Checks are not carried out on composite members or tapered members Checks using actions computed using plastic analysis are not considered Specification for Structural Steel Buildings American Institute of Steel Construction March 9 2005 Page 111 Chapter Five LRFD Page 112 The design ch
172. ypes of lateral restraints However to be compatible with other design codes Multiframe Steel Codes allows for lateral restraints at a cross section to be classified as follows e Full Restraint supports the cross section against lateral displacement of the critical flange and prevents twist of the cross section e Partial Restraint provides support against lateral displacement of the section ata point other than the critical flange and prevents twist of the cross section e Lateral Restraint resists lateral displacement of the critical flange only For the purpose of design in LRFD each of these restraint types is consider adequate to provide lateral support to the cross section at which they are applied Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two If no restraint exists at the end of a member then it should be specified as unrestrained in which case the member would be regarded as a cantilever The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange Chapter Five LRFD code The location and type of lateral restraints can be displayed in the Frame and Plot windows The display of lateral restraints can be turned on or off via the Symbols Dialog which contains options for displaying and labelling lateral restraints The restraints are drawn as a short line in the plane of th

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