AISIWIN v7.0 User`s Manual - Professional Development Hours
Contents
1. e Wall Height e Deflection Limit e Wind Pressure e Axial load if any e Load multiplier for strength load factors for LRFD e Load multiplier for deflection e Flexural bracing full discrete or optimized e Axial bracing not required if axial load 0 e Web crippling and shear parameters If Web Stiffeners at Supports O K is checked some of the studs listed as meeting the input criteria may require web stiffeners If it is not checked studs requiring web stiffeners will not be listed In addition the range of stud sizes to be investigated is required Choose a stud depth range of flange sizes and range of thicknesses AISIWIN will search the full range of studs to find all of those meeting the requirements you input The stud spacing can be fixed or set to a selected range and increment Ifa single Spacing is input only that spacing will be checked If a range of spacings is indicated all of the studs and spacings within the range will be checked As such an individual stud size may be listed several times at different spacings Flexural bracing can be optimized by selecting Optimize from the Flexural Bracing dropdown Note that if Flexural Bracing is set to Optimize only one stud spacing can be selected Flexural bracing is optimized when KyLy and KtLt are such that the flexural capacity just meets the flexural demand Note that if an axial load is entered flexural bracing optimization is not availabl2. 1 0 for members with axial loads The 2001 NAS removed this limitation AISIWIN uses C 1 14 for unbraced members 1 3 for Mid Pt braced members and 1 0 conservatively for all other conditions In addition to mechanical bracing axial loads for single and back to back members are displayed for studs with identical sheathing on each flange in accordance with Specification section D4 for specifications prior to the 2004 Supplement to the NAS only The NAS AISI Specifications do not include provisions for sheathing braced design of boxed members For sheathing braced design the moment capacity M for ASD or M for LRFD is taken as the moment at yield The sheathing parameters assumed by AISIWIN correspond to 3 8 to 5 8 inch thick gypsum board See Specification Table D4 There are several limitations on member configuration in the Specification When these limits are exceeded a warning message will appear The calculations will still proceed but the results may not be in conformance with Specification provisions It should be noted that for the 1986 edition of the Specification the allowable axial load for studs sheathed on both sides is dependent on stud spacing and can actually increase with increasing stud spacing despite the fact that the applied moment is increasing This was modified for the 1996 edition of the Specification and the change is reflected in the program The deflection ratio is also displayed for each stud
3. OF THE USER S MANUAL This User s Manual is divided into several parts The first two sections give general information regarding the use of the toolbar and menu systems and a basic overview of section data input The remaining sections detail each of the operations that can be initiated from the drop down menus Where Specification sections are referenced they are given first as the 2004 2001 NAS reference followed by a and the 1996 or 1999 edition Specification references Specific references to the 1986 edition are no longer included DIFFERENCES BETWEEN Version 7 0 and Version 6 0 AISIWIN v7 0 has several features not included in previous versions e The AISIWIN Solver feature now includes single boxed and back to back headers e A single deflection track calculator has been added based on either SSMA Tech Note 1 or the AISI Standard for Cold Formed Steel Framing Wall Stud Design provisions e Wind load data tables per ASCE 7 98 for buildings lt 60 feet in height are included and the wind pressures can be automatically loaded into the wall solver and table modules e A table of deflection limits for common wall finish materials has been added NOTE THAT THIS TABLE IS FOR REFERENCE ONLY AND DOES NOT SUPERCEDE THE CONTRACT DOCUMENTS FOR ANY PARTICULAR PROJECT e A Command Bar has been added that allows quicker navigation of the AISTWIN functions e A Submittal Quick Print button has been
4. added to print section properties along with tabular data to be used in submittals e Provisions of the 2004 Supplement to the NAS US only have been added e Provisions for circular web punchouts have been added e A basic web browser that allows the user to quickly access web sites related to AISIWIN The 2004 Supplement to the NAS incorporates some significant changes from the 2001 NAS particularly in the treatment of unstiffened elements with stress gradients These changes can lead to increases in flexural capacity particularly the weak axis flexural capacity of track and channel sections In addition changes have been made to the combined bending and web crippling provisions The 2004 Supplement to the NAS also eliminated the provisions for sheathing braced design of axial load bearing studs THE AISIWIN TOOLBAR AND MENU At startup AISIWIN displays a menu toolbar and Command bar which together control overall operation of the program The Command bar and menu direct the flow of the program and gives the user access to each of the design and settings modules Each of the Command bar and menu items is described in more detail later in this manual The toolbar contains the following controls that are common to each of the individual design modules Project input box Section drop down boxes F drop down box Punched Unpunched toggle E The calculate button E The printer button LJ The view section properties button Bea
5. and wind The calculation of ceiling joist spans is nearly identical to that for non axial load bearing walls mechanically braced The applied loads are input in the boxes labeled Dead Load Live Load and Wind Load For both ASD and LRFD design the individual loads can be modified for strength checks as well as deflection For ASD the various bending loads will be multiplied by the load multipliers input for strength and deflection when making the respective checks When using LRFD input the unfactored flexural load and the appropriate load factor All LRFD strength checks are based on factored loads while deflection is checked with the nominal load multiplied by the load factor for deflection 17 Note that AISIWIN checks only the individual load combination entered Specific load combinations required by a particular building code are not incorporated into the program The deflection limit must be entered as a ratio of the overall joist span i e for a specified deflection limit of L 480 enter 480 in the box labeled Deflection Limit L Choose the span condition by selecting one two equal or two or more equal spans Allowable spans consider the same items described for mechanically braced walls Spans based on web crippling consider the maximum reactions and the web crippling capacity of the joist If the webs of the joists are stiffened the box labeled Require Web Stiffeners at Supports is checked web crippling will
6. appropriate input information on the design forms clicking the button fills in the table with allowable spans or loads In the design modules any time a change is made to the inputs the table automatically clears To regenerate the tables with the revised inputs click the button When the section is changed via the drop down boxes on the toolbar the allowable spans or loads is automatically updated and there is no need to click the button From the design modules or the section property view form clicking the printer button sends the information on screen to the printer Note that the Wind Pressure and Deflection Limit tables are not printable The view section property button allows the user to view on screen the geometry steel properties and physical structural properties of the current section Bearing length drop down boxes are used to input the end and interior bearing lengths used in web crippling calculations Some modules do not use web crippling information However a change in either bearing length drop down will clear the tables in all of the design modules GEOMETRY AND STEEL PROPERTY INPUT Most often the sections used in cold formed steel design are standard sections supplied by one of several manufacturers To take advantage of this AISTWIN uses section databases to input geometry and steel property information Users can generate their own databases to accommodate their needs or use one of the databases supplied
7. documentation the user accepts and understands that no warranty expressed or implied is made with regard to the accuracy of the results of the program The program is intended for use by qualified professionals familiar with the design of cold formed steel members The user must understand the basis for calculations and independently verify results SETUP AISIWIN is designed to operate in the Windows environment Before setting up the program it is important to close all applications including MS Office To setup the program insert the CD in the appropriate drive and run Setup exe The setup routine will automatically create a sub folder called AISTWIN within your Program Files folder or you can choose to install it to another location Note If you choose to install AISTWIN to a folder other than the default the program may not be able to locate the section database immediately To select a database choose Settings then Database from the menu and proceed with your selection Then save your choice as the default by clicking on the button with that label AISIWIN has a built in database feature that allows users to create their own geometry databases Databases that include geometry information from the Steel Stud Manufacturer s Association SSMA and several manufacturer databases are included with the program AISIWIN can be started by any of the typical methods used to run an application in Windows ORGANIZATION
8. if the section to be investigated does not closely resemble any section from the database Choose the type of section you wish to investigate from the choices in the box labeled Section Type The graphic input screen will automatically update for the type of section chosen Choose C Stud for any section with stiffening lips Channel stud for sections without stiffeners and whose web 24 height is not modified from the input dimensions Track sections are treated similarly to channel studs except the web height is automatically adjusted from the nominal height The amount of the adjustment is twice the steel thickness plus one inside corner radius Punchout information can be entered by length and width or circular For non circular punchouts be sure the Circular check box is unchecked enter the punchout width and length in inches mm For circular punchouts check the box labeled Circular and enter the punchout diameter When entering a custom geometry for unpunched sections specify the punchout width as zero Similarly to exclude cold work of forming Specification Section A5 2 2 in the calculations enter a value of F less than the value of F specified Settings The Settings menu item allows the user to change the current and default database settings create new databases set the Specification which calculations will be based on and choose either English or metric units To change the current database select
9. menu item controls the mode of geometry and steel property input and provides another means in addition to the view section properties button of viewing section properties on screen To view section properties select Display Section Properties Selecting this item has the same affect as clicking on the view section properties button To select the geometry input mode select Geometry A sub menu will appear with three options Choosing Direct From Database puts geometry input in the database mode All geometry and steel property information will come directly from the database as controlled by the Section drop down boxes on the toolbar This is the input mode used at startup While AISIWIN is shipped with the several pre made databases additional databases can be created See the section titled Settings The default database for use at startup can also be changed from the Settings menu Selecting Customize Shape from Database allows the user to modify the geometry and steel properties of a section found in the database This can be convenient if for example you wish to use a standard section with lower yield strength or slightly different dimensions The dimensional and steel property information currently in the Section drop down boxes will be displayed on the graphic geometry customizing form To change the information change the contents of the drop down boxes to fit the specific application Selecting Input Shape can be used
10. their designs meet these requirements Floors AISIWIN calculates maximum floor joist spans based on user input dead and live loads and deflection limits for live and total loads The applied dead and live loads are entered in the drop down boxes labeled DL and LL respectively Deflection limits for dead and total loads are similarly entered in the drop down boxes labeled Total Load L and Live Load L For LRFD design the unfactored dead and live loads are input in conjunction with their individual load factors For joists with punched webs the Punched Unpunched toggle reads punched or punchout dimensions were entered in the custom geometry mode if the box labeled Consider Punched Near supports is checked allowable shear and web crippling will be reduced in accordance with the ICBO AC46 for 1996 and earlier Specifications or the appropriate specification provisions Spans are calculated for joists both with web stiffeners and without Single span and two equal continuous span conditions are considered for three on center joist spacings For the case of two equal spans the span is the distance from an outside support to the center support as shown in Figure 2 Spans with web stiffeners may be followed by a notation i e or a to indicate where web stiffeners are required The notation i indicates web stiffeners at interior supports e indicates end supports and a ind
11. 2 adopted in the 2001 NAS It is important that AISTWIN users read and understand these requirements to ensure that their designs meet these requirements Headers and Beams Allowable uniform loads ASD or maximum unfactored loads LRFD can be calculated for each of three span lengths using single boxed or back to back members Values for beams with and without web stiffeners are calculated The deflection limit is input as a ratio of the span length For both ASD and LRFD design the load can be modified for strength checks as well as deflection For ASD the bending load displayed will include the input load multipliers for strength and deflection when making the respective checks When using LRFD input appropriate load factors All LRFD strength checks are based on factored loads while deflection is checked at the unfactored bending load multiplied by the load factor for deflection Bracing intervals can be entered as FULL NONE MID Pt or THIRD Pt or an unbraced length in inches mm If FULL bracing is chosen the moment capacity is taken as the moment capacity at yield For boxed members using the 1986 or 1996 edition of the Specification the permissible unbraced length is calculated in accordance with Specification section D3 3 If a specified unbraced length exceeds the allowable for a boxed member a message indicating the maximum permissible unbraced length will be displayed Web crippling and shear ar
12. AISIWIN v7 0 User s Manual Clark y Western Lath amp Steel La Systems This version of AISIWIN v7 0 was developed for Clark Western by Devco Software Inc For questions on AISIWIN telephone 888 437 3244 For additional engineering software products visit www devcosoftware com INTRODUCTION AISIWIN is a Windows based program for calculating section properties load capacity and allowable spans for cold formed steel stud joist and track sections Calculations are based on the 2001 North American Specification NAS with inclusion of the 2004 Supplement U S provisions only as well as the American Iron and Steel Institute AISI Specification for the Design of Cold Formed Structural Members the Specification The 1996 Specification ASD and LRFD the 1999 Supplement and 1986 Specification with 1989 Addenda are included In addition except when using the 1999 Supplement and later Specifications web punchouts are treated in accordance with the International Conference of Building Officials ICBO Acceptance Criteria for Steel Studs Joists and Track AC46 For the case of the 1999 Supplement and later Specifications the punchout provisions of those documents are used The user should be familiar with each of these documents to properly understand the methods and assumptions of the program DISCLAIMER The developers have extensively verified this program and documentation However in using the program and
13. D versions of the Specification allowable moment shear and web crippling values are given If an LRFD version has been chosen the nominal strengths multiplied by the appropriate factor are displayed If the input is complete and the element dimensions comply with the code limits gross and effective properties are calculated for both the strong X X and weak Y Y directions In addition torsional properties allowable shear and web crippling loads and the quantity P Q 1996 or later edition ASD Pao 1996 or later edition LRFD or Pao 1986 edition for use in interaction equation C5 2 1 2 C5 2 are determined For Boxed or Back to Back members the properties shown are for the composite section assuming they are adequately interconnected A brief discussion of the various properties follows Effective Section Properties Strong Axis The effective neutral axis location Y g section modulus S x and allowable bending moment ASD or 6M LRFD are calculated at the yield stress as modified for cold work of forming if appropriate The moment of inertia for deflection is calculated according to Procedure I of the Specification assuming the design moment equals the allowable moment capacity Except for when using the 1999 Supplement or later specifications these properties are not reduced for web punchouts Gross Section Properties of the Full Section Strong Axis Each of the gross properties about the strong axis is based on the
14. Database from the Settings menu item and then click on the button labeled Change Database Use the standard windows file boxes to select the database you wish to design from If you would like to make your selection the default database at future startups click on the Save Current Database as Default button from the main database screen It is also possible to create or modify databases using a standard text editor Use one of the supplied databases as a template and modify it to fit your needs To change the edition of the Specification to be used in calculations select Code from the Settings menu item and then select the appropriate Specification edition To save this Specification edition as the default click on the Save Code as Default menu item The system of units for input and output can be changed by selecting Units from the Settings menu and selecting the appropriate unit system To make the selected system the default click on the Save Units as Default item View The View menu item is used to display the Command bar if it has been closed Launch Web The Launch Web menu item allows quick access to web sites pertinent to the AISITWIN software 25
15. able reactions are not modified for duration of load Note that the section input must be a track for calculations to proceed The AISI Standard for Cold Formed Steel Framing Wall Stud Design includes a number of limitations based on the range of the testing program If the inputs are outside these parameters warning messages will be displayed but calculations will display Where warning messages are displayed the user must understand that the output presented are extrapolations of the test data and should be treated accordingly To print a copy of the input and output for the Deflection Track Solver click the printer button on the toolbar Tables The Tables menu item provides access to the tabular design modules where users can determine spans and loads for various applications It also provides access to the Wind and Deflection Limit data tables Wall tables are divided into two categories Non Axial Load Bearing and Axial Load Bearing Non Axial Load Bearing walls are then subdivided into Fully Braced and Mechanically Braced walls Non Axial Load Bearing Fully Braced Walls Maximum wall heights are tabulated for walls that are fully braced by sheathing or other means and support only lateral bending loads Simple span two equal spans or two or more equal spans can be considered Using the input lateral load heights are determined based on flexure shear web crippling and deflection For multi span applications combine
16. acing intervals may be entered in inches mm or as NONE MID or THIRD points For single members loaded through their web a weak axis eccentricity equal to the distance from the web face to the centroidal axis of the effective section for pure axial load exists The associated weak axis bending moment is accounted for via equations C5 2 1 1 C5 1 and C5 2 1 2 C5 2 of the Specification In equation C5 2 1 1 C5 1 Cmy 0 85 is used A typical example of a compression member loaded through its web is a diagonal kicker brace which is attached through its web to a vertical spandrel stud on one end and a clip angle which is attached to structure on the other See Figure 3 Axial loads for 2 studs back to back are determined in accordance with Specification section C4 5 C4 1 It is assumed that members are connected so as to create a doubly symmetric section Axial loads for 2 boxed studs are also determined in accordance with the provisions for doubly symmetric sections assuming that the members are properly interconnected The axial loads printed are total loads for the two stud configuration 20 Compression brace loaded through web Reaction from Window Head Below Figure 3 Compression member loaded through web 21 BACK TO BACK STUDS BOXED STUDS Figure 4 The axial loads printed are total loads for the two stud confi
17. be modified from the toolbar For members with web height to thickness ratios exceeding 200 wall heights will not be calculated unless the Require Web Stiffeners at Supports box is checked Spans Horizontal Projection are displayed for three rafter spacings for both inward and outward uplift Rafter spacings are entered in inches mm The spacing of lateral bracing for outward uplift loads is entered either in inches mm or as NONE MID Pt THIRD Pt or FULL If FULL bracing is chosen the moment capacity will be considered the moment capacity at yield 19 Posts and Braces Allowable axial loads ASD or maximum factored axial loads Pa LRFD can be computed for single back to back and boxed members Figure 4 shows cross sections of the boxed and back to back configurations for a C stud The member length K Lx is entered in the drop down box labeled Overall Member Length KxLx For ASD design allowable axial loads will include the input load multiplier described above The allowable axial load displayed represents the nominal axial capacity divided by the input load multiplier For single studs axial loads are calculated for concentrically loaded members and members loaded through their webs Concentric axial loads are calculated in accordance with Specification section C4 The unbraced lengths KyLy and K L are taken as the user input weak axis bracing intervals Weak axis br
18. conditions For two or three spans with no bracing Cy is taken as 1 75 When using the later versions of the Specification C varies based on span and bracing configuration For simple spans Cy is taken as 1 14 for unbraced 1 3 for mid span braced and 1 0 for other bracing configurations For the two equal continuous spans Cp 13 is taken as 2 083 for the unbraced condition and conservatively taken as 1 0 for all other bracing configurations For three equal spans C is taken as 1 538 for unbraced flanges and 1 0 for all other conditions The applied lateral load is input in the box labeled Nominal Load For both ASD and LRFD design the load can be modified for strength checks as well as deflection For ASD the nominal load will be multiplied by the load multipliers for strength and deflection when making the respective checks When using LRFD design input the unfactored lateral load and the appropriate load factor All LRFD strength checks are based on factored loads while deflection is checked with the nominal load multiplied by the load factor for deflection The deflection limit must be entered as a ratio of the overall wall height i e for a specified deflection limit of L 480 enter 480 in the box labeled Deflection Limit L _ Choose the span condition by selecting one two equal or two or more equal spans Allowable heights consider the same items described for fully braced walls Wall heights are displayed for thr
19. d bending and shear and combined bending and web crippling is also considered The applied lateral load is input in the box labeled Nominal Load For both ASD and LRFD design the load can be modified for strength checks as well as deflection For ASD 12 the nominal load will be multiplied by the load multipliers for strength and deflection when making the respective checks When using LRFD input the unfactored lateral load and the appropriate load factor All LRFD strength checks are based on factored loads while deflection is checked with the nominal load multiplied by the load factor for deflection Heights based on flexure assume the studs are fully stabilized and that the allowable bending moment is the allowable moment at yield Choose the span condition by selecting one two equal or two or more equal spans For two or more equal continuous spans the minimum span based on two or three equal span conditions is displayed Heights based on shear consider the maximum shear at the ends of the studs and the allowable shear force or Py lt oP for LRFD in the web If the stud being considered is punched the user has the option of considering the web punched or unpunched in the zone of maximum shear For joists with punched webs the Punched Unpunched toggle reads punched or punchout dimensions were entered in the custom geometry mode if the box labeled Consider Punched Near supports is checked allowable shear and web cri
20. e The basic assumptions for the wall Solver are the same as for the fully braced mechanically braced and axial load bearing wall tables described below To find the studs meeting the input criteria click GO AISIWIN will search the range of studs and list all of the studs meeting the criteria Select a stud from the list by clicking on it Then preview your selection by clicking Preview or get a paper copy by clicking Print The Ceiling Solver selects simple span ceiling joists fully or mechanically braced The following inputs are required for Ceiling Solver to do its job e Joist Span e Deflection Limit e Dead Load e Live Load if any e Wind Load e Load multipliers for strength load factors for LRFD e Wind Load multiplier for deflection e Flexural bracing full discrete or optimized e Web crippling and shear parameters If Web Stiffeners at Supports O K is checked some of the joists listed as meeting the input criteria may require web stiffeners If it is not checked joists requiring web stiffeners will not be listed In addition the range of joist sizes to be investigated is required Choose a member depth range of flange sizes and range of thicknesses AISIWIN will search the full range of joists to find all of those meeting the requirements you input The joist spacing can be fixed or set to a selected range and increment Ifa single Spacing is input only that spacing will be checked I
21. e treated in accordance with the provisions described above for single span joists Wind Pressures AISIWIN includes a quick reference table of wind pressures in psf Pa for wall elements on buildings less than or equal to 60 feet in height Wind pressures are listed in accordance with ASCE 7 98 criteria Both Typical zone 4 and Corner zone 5 pressures are tabulated The wind pressures can be modified can be modified for the importance factor Iw by selecting the appropriate value from the dropdowns In addition ASCE 7 98 allows a 10 reduction in GC for roof slopes less than or equal to 10 degrees For buildings where this reduction is appropriate check the box labeled Roof Slope lt 10 degrees Wind pressures from the table can be loaded into the dropdowns for the wall design Solver and Tables by simply clicking the appropriate value from the table See the notes below the tabulated pressures for additional information 23 Deflection Limits AISIWIN includes a convenient reference for deflection limits of common wall finish materials Note that the deflection limits listed are for general guide only and does not supercede contract documents for any project Deflection limits can vary considerably from project to project Deflection limits from the table can be loaded into the dropdowns for the wall design Solver and Tables by simply clicking the appropriate value from the table Section The Section drop down
22. ed and unpunched cases in accordance with the AISI NAS provisions for the 1999 Supplement and later For earlier Specification editions ICBO AC46 is used If the section is unpunched only the full shear value is displayed For ASD designs the quantity P Q 1996 edition and later or Pao 1986 edition is calculated in accordance with Specification section C5 When using LRFD the quantity Paois given This quantity is used in interaction equations of Specification section C5 2 1 2 C5 2 Torsional Properties Torsional properties are based on the full unreduced section Web Crippling Loads Allowable Pa or nominal Pa web crippling loads are displayed for four conditions as defined in Figure 1 Allowable ASD or nominal LRFD loads for boxed members are taken as twice that of a single member For back to back members the provisions for I sections are used In addition if punchout dimensions are given a reduction factor is shown This reduction factor is calculated in accordance with the AISI NAS Specifications for 1999 or later or ICBO AC46 for earlier specifications and will be applied to the web crippling capacity if requested for a given application Refer to the instructions for individual applications for more information regarding the application of the web crippling reduction factor No web crippling loads are displayed if the web height to thickness ratio exceeds 200 since such members require stiffeners at all concent
23. ee stud spacings and three bracing configurations Stud spacings are entered in inches mm The lateral bracing interval is entered either in inches mm or as NONE MID Pt or THIRD Pt points The user may change each of the stud spacings and lateral bracing intervals Click the calculate button on the toolbar to fill in the heights table Axial Load Bearing Walls AISIWIN calculates allowable axial loads ASD or maximum factored axial loads Pu LRFD for studs with combined bending and compressive loads Interaction formulas per Specification section C5 are used to determine the maximum axial load P which the stud can carry in combination with the user specified bending load by setting the interaction values to 1 0 Input the overall wall height in the drop down box labeled Overall Wall Height Bending moment is calculated based on a simple span condition at the specified wall height If the box labeled Consider Fully Braced for Bending is checked the moment capacity used in the interaction equations will be the moment capacity at yield If this box is not checked lateral stability will be considered in accordance with Specification section C3 1 2 with KyLy and K L equal to the bracing interval input Lateral loads in psf N m are input in the drop down box labeled Lateral Load The combined bending and axial load interactions will be checked using the load multipliers on both lateral and axial l
24. es to be investigated is required Choose a member depth range of flange sizes and range of thicknesses AISTWIN will search the full range of joists to find all of those meeting the requirements you input The joist spacing can be fixed or set to a selected range and increment Ifa single spacing is input only that spacing will be checked Ifa range of spacings is indicated all of the joists and spacings within the range will be checked As such an individual joist size may be listed several times at different spacings To find the joists meeting the input criteria click GO AISIWIN will search the range of joists and list all that meet the criteria Select a joist from the list by clicking on it Then preview your selection by clicking Preview or get a paper copy by clicking Print The Header Solver selects single boxed or back to back headers for simple span conditions The following inputs are required for Header Solver to do its job e Header Span e Dead Live and or Wind Load e Load multipliers or load factors for LRFD for strength for each load type e Load multiplier for deflection wind load only e Deflection Limit e Flexural bracing e Web crippling and shear parameters If Web Stiffeners at Supports O K is checked some of the joists listed as meeting the input criteria may require web stiffeners If it is not checked joists requiring web stiffeners will not be listed In addition the range
25. f a range of spacings is indicated all of the joists and spacings within the range will be checked As such an individual joist size may be listed several times at different spacings Flexural bracing can be optimized by selecting Optimize from the Flexural Bracing dropdown Note that if Flexural Bracing is set to Optimize only one stud spacing can be selected Flexural bracing is optimized when K L and K L are such that the flexural capacity just meets the flexural demand To find the joists meeting the input criteria click GO AISIWIN will search the range of joists and list all that meet the criteria Select a joist from the list by clicking on it Then preview your selection by clicking Preview or get a paper copy by clicking Print The Floor Solver selects floor joists in one span or two equal span configurations The following inputs are required for Floor Solver to do its job e Joist Span e Dead Load 10 e Live Load e Span Condition one or two equal spans e Alternate span loading check for two equal span condition only e Total Load Deflection Limit e Live Load Deflection Limit e Load Factors LRFD Only e Web crippling and shear parameters If Web Stiffeners at Supports O K is checked some of the joists listed as meeting the input criteria may require web stiffeners If it is not checked joists requiring web stiffeners will not be listed In addition the range of joist siz
26. full unreduced geometry of the section Section Properties Weak Axis Both gross and effective properties are displayed for the weak axis under this heading Gross properties are based on the full unreduced geometry of the section Effective properties are based on initiation of yield The calculation of effective properties for bending about the weak axis of single members considers cases for both the web in compression and in tension and records the minimum value of section modulus and allowable weak axis bending moment ASD or OM LRFD For the case of the web in compression with punched webs the effective web width is based on the unstiffened strip approach discussed in ICBO AC46 and in the 1996 and later versions of the Specification For C studs flanges are treated as webs with stress gradients per Specification section B2 3 The effective flange widths of channel studs and track sections are based on Specification section B3 2 for the 2001 NAS and earlier For the 2004 Supplement to the NAS section B3 2 is used Weak axis flexural strength is not computed for boxed or back to back sections Other Section Property Data For members with punchouts the net area at punchout locations is displayed For both punched and unpunched members the weight per unit length lb ft is calculated based on the gross unreduced area of the section If punchout dimensions are given the allowable shear will be calculated for both the punch
27. guration The bracing intervals can be modified by the user by entering the desired interval in inches mm or specifying NONE MID Pt or THIRD Pt bracing If no bracing interval is entered the unbraced length will be taken as the overall length of the member A diagram of Back to Back and Boxed studs is shown on screen as they are selected and are given above in Figure 4 The maximum KL r ratio K L rx or KyLy ry is also calculated for each bracing interval and displayed If the ratio exceeds 300 no axial loads are computed The provisions for built up members with axial load changed in the 2001 NAS from previous versions of the Specification Section C4 5 of the 2001 NAS defines a modified KL r based on the fastener spacing between members the slenderness ratio of the built up section and the minimum radius of gyration of the individual sections making up the built up member As such fastener spacing is required for calculating axial capacity of boxed and back to back members using the 2001 NAS This requirement is reflected in AISIWIN v6 0 with the addition of a dropdown input for fastener spacing that appears when boxed or back to back members are selected Note that section C4 5 of the 2001 NAS also places limits on the spacing of the fasteners If those limits are not met AISIWIN will not calculate axial capacities There are also requirements for connections at ends of built up members and for fastener capacity 2
28. icates all supports 66599 1 Some building codes require serviceability checks that consider alternate span live loading For deflection of a two span joist this can be the controlling criterion The user can choose whether to consider alternate span loading for deflection calculations on two span joists To consider deflection with alternate span loading click on the box labeled Check Alternate Span Loading For LRFD design deflection is calculated with unfactored loads 16 kK oF Span Span Figure 2 Span measurement Allowable single spans are determined as the minimum value from flexure shear total deflection and live load deflection For joists without web stiffeners web crippling is also considered The same criteria used to determine allowable single spans are used for two equal continuous spans In addition combined bending and shear AISI Specification Section C3 3 and combined bending and web crippling for joists without web stiffeners AISI Specification section C3 5 are considered If the web height to thickness ratio exceeds 200 web stiffeners are required at supports and as such no spans are calculated for the unstiffened case Ceilings Ceilings are generally sheathed on only their bottom flanges Therefore the stability of ceiling joists in bending must be calculated in accordance with Specification section C3 1 2 Ceiling bending loads also may consist of several components e g dead live
29. not be considered If web crippling is to be considered the bearing lengths can be modified from the toolbar For members with web height to thickness ratios exceeding 200 wall heights will not be calculated unless the Require Web Stiffeners at Supports box is checked Spans are displayed for three joist spacings and three bracing intervals Joist spacings are entered in inches mm The lateral bracing interval is entered either in inches mm or as NONE MID Pt THIRD Pt or FULL If FULL bracing is chosen the moment capacity will be considered the moment capacity at yield The user may change each of the joist spacings and lateral bracing intervals Rafters Rafters may be subject to gravity and inward wind loads as well as outward uplift loads In addition they are often sheathed on only their top flanges Therefore the unbraced length of the compression flange for rafters in bending may be different for inward and outward load AISIWIN assumes that rafters are fully braced for inward loads similar to floor joists However bridging may be required in order to minimize rotation For outward uplift loads rafters can be designed as unbraced fully braced or braced at any interval desired Enter the bracing interval for uplift loads in the box labeled Flexural Bracing for Uplift Note that AISIWIN analyzes rafters for flexural loads only Axial loads as may be induced by pinching forces a
30. oads as input If however the maximum allowable load P including the load multipliers exceeds the allowable pure axial load of the stud under concentric axial load only without a multiplier the unmodified allowable pure concentric axial load of the stud will be displayed Deflection is calculated at the input lateral load multiplied by the factor for deflection 14 For LRFD design input the unfactored lateral load and the load factor Deflection is calculated at the nominal load multiplied by the load factor for deflection Axial loads are calculated for three weak axis bracing intervals and three on center stud spacings Modifying the contents of the associated drop down boxes can change any of these parameters On center stud spacings are entered in inches mm For weak axis bracing the input can be in inches mm or NONE MID or THIRD can be chosen If data is entered that is not numerical or one of the three interval designations the weak axis bracing interval will be considered to be the overall wall height For calculating stresses in accordance with Specification section C4 the unbraced length for torsion K L is taken as the spacing of weak axis bracing K Ly In the interaction equation C5 2 1 1 C5 1 of the Specification Cmx 1 0 For boxed members torsional buckling is not considered AISI Specifications prior to the 2001 NAS required that C as used in the flexural stability checks be taken as
31. of header sizes to be investigated is required along with the configuration single boxed or back to back Choose a member depth range of flange sizes and range of thicknesses AISIWIN will search the full range of headers to find all of those meeting the requirements you input Flexural bracing can be optimized by selecting Optimize from the Flexural Bracing dropdown Flexural bracing is optimized when K Ly and KL are such that the flexural capacity just meets the flexural demand 11 To find the headers meeting the input criteria click GO AISIWIN will search the range of joists and list all that meet the criteria Select a joist from the list by clicking on it Then preview your selection by clicking Preview or get a paper copy by clicking Print The Deflection Track Solver determines allowable reactions on track legs of single deflection tracks Either the provisions of the Steel Stud Manufacturer s Association SSMA Tech Note 1 or the AISI Standard for Cold Formed Steel Framing Wall Stud Design 2004 Edition section C4 3 may be used Inputs required include the gap dimension stud flange width and stud spacing Based on these inputs the allowable top of stud reaction is computed Intermediate results such as the effective plate bending width bere for SSMA Tech Note 1 and Wa for the AISI Standard for Cold Formed Steel Framing Wall Stud Design are also displayed Note that the allow
32. ppling will be reduced in accordance with the ICBO AC46 for 1996 and earlier Specifications or the appropriate specification provisions Heights based on web crippling consider the maximum reaction and the web crippling capacity for the stud If the webs of the studs are stiffened the box labeled Require Web Stiffeners at Supports is checked web crippling will not be considered If web crippling is to be considered the bearing lengths can be modified from the toolbar For members with web height to thickness ratios exceeding 200 wall heights will not be calculated unless the Require Web Stiffeners at Supports box is checked Wall heights are displayed for three stud spacings and deflection ratios any of which may be modified by the user Stud spacing is input in inches mm and deflection limits are input as a ratio of the overall wall height Click the calculate button on the toolbar to fill in the allowable wall heights table Non Axial Load Bearing Mechanically Braced walls Walls that do not have adequate bracing on each flange over the entire length of the stud can be designed as mechanically braced walls The design criteria for mechanically braced walls are similar to that for fully braced walls except that the flexural capacity is based on the lateral stability of the stud in bending in accordance with Specification section C3 1 2 When using the 1986 Specification the quantity C is taken as 1 0 for simple span
33. rated loads The 2001 NAS and later specifications have provisions for Fastened to Support and Unfastened web crippling However provisions are not included for all section types and web crippling conditions AISIWIN uses the Fastened to Support values whenever possible and resort the Unfastened data where there is no other alternative As such if members are not intended to be fastened to supports the web crippling strength of the members should be determined using a method other than AISTWIN UNIFORM LOAD rate Ofte C REPRESENTS WEB CRIPPLING CONDITION NUMBER Figure 1 Web crippling conditions Using the Menu File From File the user can select Print or Exit Selecting Print has the same affect as clicking on the toolbar printer button The Exit item closes AISTWIN any current information will be lost Solver The Solver Menu item provides access to the Wall Ceiling Floor and Header Solver modules These powerful new tools allow design of wall ceiling floor and header members by inputting your exact design requirements and allowing AISIWIN to find the members that can meet the requirements The Solver menu also includes the calculator for single Deflection Track The Wall Solver selects simple span wall studs fully or mechanically braced and with or without axial loads The following inputs are required for Wall solver to do its job
34. ring length drop down boxes for interior and end bearing The Project input box allows the user to enter a project name or heading that will appear on printed reports To enter a heading click on the box and type The Section drop down boxes are used to input section geometry information from the database if in database input mode or to input a special designation if in custom geometry input mode At startup input is in the database mode with information from the default database loaded into the drop down boxes The section designation can be changed at any time and the physical structural properties allowable spans or load capacity will automatically be re calculated The F drop down box is used to change the yield point to 33 or 50 ksi at run time without leaving the design modules Note that only 33 and 50 ksi are available from the dropdown regardless of the yield point set in the database When 33 ksi is selected an ultimate stress of 45 ksi is assumed for cold work of forming calculations When 50 ksi is selected an ultimate stress of 65 ksi is assumed for cold work of forming calculations The Punched Unpunched toggle is used to specify if the section will have web punchouts Some manufacturers will supply their standard products either with or without punchouts This applies only to the database input mode The or calculate button is used in the design modules to fill in the load or span tables After providing all of the
35. spacing so the user can compare the deflection with the applicable serviceability criteria In addition the maximum KL r ratio KxL rx or KyLy ry is calculated and displayed Web crippling is not considered for the determination of axial loads but should be checked against the allowable web crippling load for the particular stud and bearing condition Web crippling capacity is given at the bottom of the section property printouts 15 The provisions for built up members with axial load changed in the 2001 NAS from previous versions of the Specification Section C4 5 of the 2001 NAS defines a modified KL r based on the fastener spacing between members the slenderness ratio of the built up section and the minimum radius of gyration of the individual sections making up the built up member As such fastener spacing is required for calculating axial capacity of boxed and back to back members using the 2001 NAS This requirement is reflected in AISIWIN v6 0 with the addition of a dropdown input for fastener spacing that appears when boxed or back to back members are selected Note that section C4 5 of the 2001 NAS also places limits on the spacing of the fasteners If those limits are not met AISIWIN will not calculate axial capacities There are also requirements for connections at ends of built up members and for fastener capacity adopted in the 2001 NAS It is important that AISTWIN users read and understand these requirements to ensure that
36. t unsupported ridges or those due to parallel components of gravity loads are not considered Rafters may also be sloped changing the magnitude of the perpendicular component of gravity loads Also since AISIWIN reports allowable spans on the horizontal projection the actual member length may be longer than the listed span The rafter slope can be entered in either rise 12 or degrees Select the slope units from rightmost dropdown in the slope input box The slope is then entered in the slope dropdown Slopes less than or equal to 12 12 45 degrees may be used 18 Inward loads are entered in the boxes labeled Dead Load Live Snow Load and Inward Wind Load For both ASD and LRFD design the individual loads can be modified for strength checks as well as deflection For ASD the bending load will be multiplied by the load multipliers input for strength and deflection when making the respective checks When using LRFD input the unfactored loads and appropriate load factors All LRFD strength checks are based on factored loads while deflection is checked with the nominal load multiplied by the load factor for deflection The outward uplift load and the resisting dead load are input in the boxes labeled Inward Wind Load and Resisting DL For both ASD and LRFD design the individual loads can be modified for strength checks as well as deflection For ASD the bending load will be multiplied by the load multipliers input for strength and deflection
37. when making the respective checks When using LRFD input the unfactored lateral load and appropriate load factor All LRFD strength checks are based on factored loads while deflection is checked with the nominal load multiplied by the load factor for deflection Since bending in the rafter is a function of the perpendicular component of the loads gravity loads are modified for slope Dead load is multiplied by the cosine of the rafter slope Live and snow loads are multiplied by cos slope since these loads are specified in most model building codes as projected on the horizontal plane Wind load is generally considered to act perpendicular to the surface and therefore are not modified for slope Note that AISIWIN checks only the individual load combination entered Specific load combinations required by a particular building code are not incorporated into the program Both dead and total load deflection limits must be entered as a ratio of the overall rafter span i e for a specified deflection limit of L 180 enter 180 in the box labeled Dead Load L or Total Load L Spans based on web crippling consider the maximum reaction perpendicular to the long axis of the member and the web crippling capacity of the rafter If the webs of the rafters are stiffened the box labeled Require Web Stiffeners at Supports is checked web crippling will not be considered If web crippling is to be considered the bearing lengths can
38. with the program It is sometimes necessary to design a section that is not part of any manufacturer s standard product line This can easily be done within AISIWIN by selecting one of two custom geometry input methods The first custom input mode allows the user to take data from a standard database shape and modify it The second mode provides for total flexibility of input with no information from the database Each of these methods is described in the paragraphs that follow VIEWING PHYSICAL STRUCTURAL PROPERTIES With the geometry entered physical structural properties can be viewed by clicking the view section properties command button or by selecting Display Section Properties from the Section menu item Input geometry and steel properties are first checked for completeness If the information is incomplete a message will be displayed indicating what information needs to be entered or corrected In addition element width to thickness ratios are verified per Specification section B1 1 If these ratios exceed Specification limits a message will be displayed indicating the element which requires modification When calculations are being performed using the 1999 Supplement or later Specifications punchout dimensions are also verified relative to the shear and web crippling reductions If the punchouts fall outside the published parameters for the reduction equations a warning message is shown but the calculations will proceed For AS
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