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Pile Oasys Geo Suite for Windows

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1. AP tz A 7000 000 1 008 TART I m n ENEEN 11 Cell A 2 Description the name of the curve Material Type selection has to be made between two materials sand and clay Z the movement required to mobilise maximum stress This is active only when the material type Is sand tres Imax the ratio of mobilised stress to maximum stress This is active only when the material type is clay 5 13 5 Vijayvergiya Each record in the Vijayvergiya t z Curves table view consists of the following items EE Pilel Vijayvergiya t z Curves Defaults 1000 000 1 jVijgwemyatz S 0 300 000 pe 1 Cell B 1 Copyright Oasys 1997 2014 2 Pile Oasys Geo Suite for Windows Description the name of the curve Z the movement required to mobilise maximum stress This value is often around 0 3 inches for sands 5 13 6 User Specified Each record in the User Specified t z Curves table view consists of the following items EE temp2000 pls User Spec t z Curves User 5pec z 1 Add Curve Normalised shaft shear stress t tmax 25 8823 41 4706 77647 po 0 0000 E tu E 5 wo a i 7 7 a E wo tu AE oo T a m E L a 30 40 50 60 70 280 Local shaft displacement z mm Press TAB to start a new record z titma Disp i9 Absolute 7 Normalised Local shaft displa
2. A player 1 Alluvium 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00 5 0 00 0 00 0 00 000 g Soil Profile 1 ASoilProfle2f 4 En of the soil layer Layer Material the soil material that is present in the layer Copyright Oasys 1997 2014 108 Pile Oasys Geo Suite for Windows Vertical effective stress user defined vertical effective stress profile Horizontal effective stress user defined horizontal effective stress profile The vertical and horizontal effective stresses at any intermediate level are linearly interpolated between the top and bottom of layer 5 12 Nq Phi Curves Each record in the N Phi table view consists of the following items Berezantzev pls Nq Phi Curves Nonlinear Curve 1 Add Curve O J A B Phi Deg Ma Defaults 18 5234 14 8148 29 7059 4H 5082 EN Hearing Capacity Factor Ma B FO Drained Friction Angle Phi Press lt TAB gt bo start a new record Fhi Mq Grid max 90 4 gt Y mas 100 4 Linear Log Phi the effective friction angle Ng the value of bearing capacity factor at the given friction angle This table view is used by the Berezantzev 1961 and Bolton 1984 methods for calculating Na 5 13 t z Curve Data There are 6 types of t z curves currently supported by the program The following sections will cover these options in detail Copyright Oasys 199
3. Company Info allows changes to the company name and logo on the top of each printed page To add a bitmap enter the full path of the bitmap file The bitmap will appear fitted into a space approximately 4cm by 1cm The aspect ratio will be maintained For Arup versions of the program the bitmap option is not available Copyright Oasys 1997 2014 4 Pile Oasys Geo Suite for Windows Company Information 1 4 Enter the full path of the bitmap file that you would like to appear on pour printed output The bitmap will be fitted inta a space approximately 4 cm by 1 cm but its aspect ratio will be maintained select the company name that you would like to appear on your printed output Page Setup opens the Page Setup dialog allowing the style of output for printed text and graphics to be selected lf Calculation Sheet Layout is selected the page is formatted as a calculation sheet with details inserted in the page header If Logo is selected the company logo is inserted in the top left corner of the page If Border is selected this gives a border but no header information If Clipped is selected the output is clipped leaving a space for the logo This has no effect on text output Step by Step Guide To perform capacity and settlement analysis of a pile follow the steps listed below The data file should be saved at frequent intervals Item 1 2 Description Begin a new data file by selecting Fil
4. The ultimate bearing capacity Q of solid piles is Q Qe Q j Q et where Q cumulative skin or shaft friction Q end bearing Q negative skin friction For piles in tension Q Q 0 Hollow piles The ultimate bearing capacity Q of hollow piles is given by Q MinimUM Q lugged gt Qunplugged case1 Qunplugged case2 where Qotuagea IS the plugged capacity of the hollow pile lage jeer lo the unplugged capacity for case 1 oode is the unplugged capacity for case 2 The above quantities are described below Copyright Oasys 1997 2014 wo Pile Oasys Geo Suite for Windows 2 1 3 2 Plugged Capacity The plugged capacity of hollow piles is given by Q isggad g Qo A Qu F Qe i Quist Ext where Q e cumulative external skin friction exclusive of negative skin friction kN Qy end bearing acting over the soil plug area kN Q w end bearing acting over the pile wall area kN Qhsr ex external negative skin friction For piles in tension Qo Qw Q 0 nsf Ext E 2 1 3 3 Unplugged Capacity The unplugged capacity of hollow piles is given by Q Qu adm eg Q unplugged nsf Ext nsf Int where Q Cumulative internal skin friction exclusive of negative skin friction KN Q e The cumulative external skin friction exclusive of negative skin friction kN Q w end bearing acting over the pile wall area kN Qe Ext external negative skin friction Qst int internal negative skin friction When dr
5. lP dc saca 8 In z T D a 1 20 8 1In z T D 2h z r 4h 3 48 z 2 hr h z r x 2h z l h D D i where h L eae aa 07 4 D 27 i 1 4 Displacement of Base due to the Base itself Copyright Oasys 1997 2014 EEN Pile Oasys Geo Suite for Windows Surface I ME EMI zT o 2H h c 2H h c Higid Base Imaginary surface Geometry of Integration Over Pile Base Area lop with Cc SL Ky Ey zz 0 therefore Copyright Oasys 1997 2014 Method of Analysis 35 z 1 dy o 5 88 2 H z zt 7 7 Ino eis 128 803R I Hu 1 16 d gt PEERS 2 z gR 2 283 where di R ac qp Z 2L Displacement of Point i due to the Base 1 2m dy 2 lin I rdr de d Jo 0 with QE RI zi x r7 2rxcos8 R z x r 2rxcos8 z 20 the integration with respect to r is Pr dr A ara 3 49 RES A In r A Xo Br 1 9 R2 A7 xs 5 128 882 x Aln r A x rA Ri Ri A GA Ri 2A r A 2cz z c AAA CDMA 3 422 2ez 2c where RB af x A xcos xo r 2Ar 4 R Bes Lx H hj Copyright Oasys 1997 2014 NES Pile Oasys Geo Suite for Windows x 1 2Ar 4 Ri Qe 2c CaL The limit of integration is from O to dy 2 The integration with respect to is evaluated by
6. 0 0 1 0000 2 0000 3 0000 4 0000 5 0000 6 0000 7 0000 8 0000 3 0000 10 000 11 000 12 000 13 000 14 000 15 000 16 000 17 000 oo cm in WO alte 13 dE 155 15 iF 19 al ade ad at o Pile length m 0000 0000 0000 0000 0000 0000 10 ooo 000 Und 000 ooo ono ono ono 000 ono aod ono 000 000 ono ooo Ultimate Cumulative hase Capacity ip KH 309 60 1131 0 leme mi 1413 7 LS EE 40 ES Erde st SR E 295 ERI 335 355 376 396 417 ipsu 450 475 490 173 193 13 65 11 47 B3 16 a4 20 b 61 a7 33 6 amp 9 04 40 T external Fricti 0 on gl kH Ieee 196 Ann 3273 3z3 37 Toar 506 bl bbe T50 a545 Sup 1056 de a a 1293 qup 1558 1701 1550 2006 2169 15 og 66 46 16 75 Baz 68 32 75 aT a7 Tb um Mw Ww O in 00 CO Hegative skin friction inst 5000000505000 05050000 00 000 E Do nmn S a A mn BA m S ma S m G ma O m S mas S m D m SA m G m SA m S ma G m O ma G 00 0 O Ultimate capacity KH 1133 8 1327 9 1529 0 l737 2 476 550 632 720 Bls5 alf 1025 1141 1265 1392 1527 1570 1519 1975 2136 2306 2464 2660 Boob e M J LR D m w Co ob D a O ug 2 ao A i i r2 c r2 Allorable Limiting Capacity criterion kH 206 UG 34 646 1950
7. 2Pn 1 Pn 3 295 Copyright Oasys 1997 2014 Method of Analysis 39 therefore EPR Pa y gl 0 2p 2 2p4 1 Pn 3 2P iv For pile base 8 a Pn py T a 8p g 3 a Pn i Pp 2 Ip 8 P SO Pn i 7 90s t Gpp _ Po Pe 38 E therefore dEPR 4 m 32 Pp TA 82 dR z Pn 1 Pn 3 Pb dEPR 4 l 32 Po 7 752 3F0n 1 12f Pn gt f Pe where R A A ad T l aR Pile Stiffness The pile stiffness matrix is given by 1 1 0 Q0 0 i 2 1 0 0 dEPR a ds e oes 0 4 6210 0 0 0 0 1 2 1 0 0 0 0 02 2 5 3 2 0 0 0 0 0 133f 12f 10867f Copyright Oasys 1997 2014 E NN Pile Oasys Geo Suite for Windows 2 2 2 2 2 2 1 t z Curves Soil Stiffness Matrix The soil stiffness matrix is given by ki 0 0 0 0 0 0 0 k 00 0 0 0 0 0 0 0 0 O0 0 0 0 0 0 0 0 0 00k 0 0 0 0 00 0 0 0 0 0 0 0 O0 k where k is the stiffness at node i obtained from the t z curve associated with the soil material in which the node lies For the last node i e for the base the stiffness is sum of the stiffness obtained from t z curve and the stiffness obtained from the tip load curve associated with the soil material in which the last node lies Kshaf t node Kr z shaft node I ase nede ki z base node IK loa bas mds If the node lies at the junction of two layers then the top layers curve is used The stiffness
8. Settlement Data Notes B Material Properties Settlement analysis i Undrained Materials 2 i Drained Materials 1 Analysis Options Soil Profiles 1 Groundwater 1 Datum type Elevation based 2 Soil Profile Groundwater Map 1 PERICIA stress profile le A Effective Stress Profiles 1 eS pronun ginis eii d x S Poisson s ratio of soil 0 250000 E Nq Phi Curves 1 Young s modulus of soil above toe level of pile 20000 0 kPa Nonlinear Curve 1 3 Young s modulus of soil below toe level of pile 40000 0 kPa t z Curve Data Number of pile elements 10 i i Elastic Plastic Increment type Loads only m Chin amp Poulos 1991 Number of load increments 1000 P Empirical API 1993 Increment results would be printed once every 1000 increments i i OTA Include effect of soil above pile base in base displacement Yes Empirical Vijayvergiya 1977 A i calculation User Specified Er Tip Load Curve Data Pile Properties i Elastic Plastic i E Chin amp Poulos 1991 Nila erma Calia The graphical representation of the soil layers the pile and the cross section of the pile is shown Berezantzev pls Graphical Output SEE BE dE B il gt Cross section 1 4 800m NO LOAD INC 4 Stress kPa 80 00 T Undrained Cohesion i v rd Unit Shaft Friction Pore water pressure Solid circular pile Ultimate Skin Friction C Vert Eff Stress C Diamet
9. Solid 93 Solution Algorithm 20 Square 93 Standard Toolbar 2 Stress 1 Support 75 T Table View 2 Tabular Output 2 Tabulated Output 125 Tension 12 Titles 78 Titles Window Bitmaps 79 Toolbar 2 128 Total Bearing Capacity 1 12 Total Stress 8 20 98 Total Stress Approach 8 10 Type 93 U ULS 18 Ultimate Bearing Capacity 13 16 Ultimate Capacity 13 18 Ultimate Limit State 18 Under ream 92 93 97 Underream Data 97 Undrained 1 8 132 Unit Wt 105 Units 79 Units and Preferences 79 Unplugged 93 Unplugged Capacity 14 User Interface 2 User specified 21 User specified Datum 1 V Vertical Effective Stress 10 Vertical Stress Profile 20 W Wall Thickness at Base 96 Warnings Errors 124 Web 96 Width along Flanges 96 WMF 1 128 132 Working Load 132 Working Load Approach 16 Copyright Oasys 1997 2014 Copyright Oasys 1997 2014 Endnotes 2 after index 137
10. 2014 59 Pile Oasys Geo Suite for Windows Force i Fy my F my F qu P qi e A A cf m i Go F Qo So i S E T ES i i i 2 S c J d Hi i if f 4 m Displacement i F i r F F i i rj i Fi e f the spring is loaded untill plastic deformation in one direction unloaded to plastic deformation again in the opposite direction and again reloaded in the original direction the reloading curve runs parallel to the initial loading curve and merges with the perfectly plastic zone of the inital loading curve Copyright Oasys 1997 2014 Method of Analysis so eft I qi Flut m r C2 _ f 2 i r O i LL J fi F i i i H i F f F H l f fd SL PT P Displacement F p i i F F i i F i k i F NI An alternative case where the the last load displacement curve shifts to the left of initial loading curve is given below Copyright Oasys 1997 2014 e Pile Oasys Geo Suite for Windows Force Displacement The slope of the unloading curve after plastic deformation sets in is given by the slope of the initial loading curve at the origin This poses a a problem for the Vijayvergiya API curve since the slope of the parabolic force displacement curve is infinity at the origin Hence the program uses the slope of the first segment of the 10 segments used in modelling this curve Post peak behaviour API Clay and other user defined curves with softening be
11. FF E displacement at element i in a soil with E due to a unit load at element i Y E displacement at element j in a soil with E due to a unit load at element j Copyright Oasys 1997 2014 Method of Analysis 31 2 2 1 2 Integration of Mindlin s equations Displacement of Point i due to Stress on Element j i 1 8 cn r 2 E T Ji R8 i is No Geometry of Single Pile For a general point 7 the value of li IS Copyright Oasys 1997 2014 32 Pile Oasys Geo Suite for Windows 1 influence factor for vertical displacement due to a vertical point load From Mindlin s equation IP is given by 1 9 zu 6 4 5 128 8937 3 48 z 2cz 2c 6cz z c 8n 1 8 R R R y E where z h c d h c Ry x dx cos28 zj p BP x dx cos28 z The integral with respect to c is given by Pde 1 41 38 Iniz D4 4 8 1 22 2 Inlz 0 C 8n 1 tp n 1 x E n A 2h z r 4h 3 48 z 2 hr h z r D D i where Di D r 4 z and the limits of integration are z y from A j l dto h jd z from h j I d to h 4 jd The integration with respect to is evaluated by numerical means Displacement of Base Centre due to Stress on Element j Copyright Oasys 1997 2014 Method of Analysis 33 the integral with respect to c is 1 8 z
12. Poulos 1991 These show a continuous degradation of stiffness with increasing load The equation for the initial loading curve for the shaft is given by a de m 2 7 _ Eglo l Do tg dE a EN max 1 Ry Ef where rj is the radius of the pile To is the pile soil interface shear stress t is the limiting shear stress r Is the empirical distance at which the shear stress in the soil becomes negligible R is a hyperbolic constant which controls the shape of the Force displacement curve Gmax is the initial shear modulus The displacement at maximum force is controlled by a hyperbolic constant R For R 1 the pile displacement is infinite at maximum force The program generates 10 t z pairs between tg 0 Copyright Oasys 1997 2014 NN Pile Oasys Geo Suite for Windows and TT Typical t z curve of this type is shown below Force Displacement The equation for the initial loading curve for the base is given by P ko 1 Pr where p is the mobilised shear load R is the hyperbolic curve fitting constant for the base p is the limiting base load k is the initial stiffness at the base and is given by 40 7 LET a 8 1 95 In the above expression E and G are the initial Young s modulus and shear modulus of the soil respectively and v is the Poisson s ratio of the soil Typical tip load curve of this type is given below Copyright Oasys 1997 2014
13. This is active only when the Design resistance method is chosen The following fields relate to Friction data Skin friction computation method either Beta Method or Earth Pressure Method value of beta friction angle Coefficient of earth pressure K is used to calculate horizontal effective stress from vertical effective stress This field is enabled when Effective stresses are selected in the Analysis Options Limiting value Specified select Yes to specify a limiting value Value the friction value is limited to this value When the limiting value of the frictional shear stress is entered as zero the maximum allowable frictional shear stress between the pile and the soil is assumed to be infinite t z curve the stress displacement curve to be used for calculations if the settlement calculation method selected is t z curves This column is active only when the analysis type in the Analysis Options is Settlement and the calculation method in the Settlement Data is t z curves The following fields relate to End bearing N computation method any of user specified Bolton or Berezantzev N value of bearing capacity factor Na value of effective friction angle for the soil profile Dp value of angle of internal friction corresponding to the soil of overburden Refer to Berezantzev method Q oy value of critical state angle of friction Copyright Oasys 1997 2014 102 Pile Oasys Ge
14. by clicking on the restore zoom icon as shown here aA Smaller Larger font adjusts font sizes on the Graphical Output View Edit colours allows line and fill colours to be edited Save BMP saves the file as a bitmap rr m T m Copy copies the graphical view to the clip board Capacity Ty Vertical effective stress toggles the vertical effective stress plot Th Horizontal effective stress toggles the horizontal effective stress plot Y Pore water pressure toggles the pore water pressure plot Ge Undrained cohesion toggles the undrained cohesion plot fini Unit shaft friction toggles the unit shaft friction plot Br External skin friction compression toggles the external skin friction compression plot tert Total skin friction compression toggles the total skin friction compression plot Dr Total skin friction tension toggles the total skin friction tension plot Copyright Oasys 1997 2014 ow Pile Oasys Geo Suite for Windows HE Axis provides a reference grid behind the drawing a End bearing capacity toggles the end bearing capacity plot E Internal skin friction toggles the internal skin friction plot la Wall end bearing toggles the wall end bearing plot E Plugged end bearing toggles the plugged end bearing plot db Plugged capacity toggles the plugged capacity plot Il Unplugged capacity toggles the unplugged capacity plot H Unplugged capacity auto plugged toggles
15. kPa Deg Deg Deg kPa kPa kPa Defaults 1 00 Nq specified No Nq specified 0 00 Berezantzev Ak Bk C 1 00 Nq specified 0 00 Nq specified 0 00 Ng specified 0 00 Nq specified 0 00 Nq specified 0 00 4j Nal General A Friction A Bearing Enter material name The M1 set values are always 1 0 M2 set values are different from 1 00 and are specified in the code for only some parameters Cu etc However skin friction and end bearing computations can be specified that do not explicitly depend on these parameters For example q or q can be specified directly or N can be used to calculate the same In these situations the corresponding M2 parameters would need to be specified as these are not available in the code The program uses these M2 values in end bearing skin friction computations Note The M2 parameters are used for certain design approaches eg DA1 Combination 2 DAS Copyright Oasys 1997 2014 Input Data 103 5 8 Soil Profiles Multiple soil profiles can be selected in the Soil Profiles table view Each tab corresponds to one soil profile Existing soil profiles can be edited or deleted and new soil profiles can be added using the context menu obtained by right clicking on any tab Each record in the table view consists of the following items Test3res rene Soil Profiles Dox Sass below AM to Layer iiim level Material o BE aon eun b OU aa s Den Mo 1 00
16. non cyclic sub stage Half cycle 1 sub stage 3 Opening the Program The following provides details of all the information required to run the Pile program On selection of the Pile program the main screen will open Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows Pile 19 5 E File View Tools Help Pi X eG SB 90dQ aE is 5 A AAS To start a new project file select Create a new file option on the opening screen Nelcome to Pile B or 19 5 build 1 m m Create a new file CO Open an existing File CO Select recent File Manuali pls depths3 pls Manual pls 600 O1 pls Show this welcome screen on startup ox If the Show this welcome screen on startup option is unchecked then this dialog will not be Copyright Oasys 1997 2014 Opening the Program displayed on startup In that case a new data file may be created by clicking File New on main menu or the corresponding icon P on toolbar This will open a new Titles window and allow you to proceed To display Welcome to Pile at startup check Show welcome screen in the Preferences dialog The Preferences dialog can be accessed via Tools Preferences It is possible to open more than one data file at any one time The file name is therefore displayed in the title bar at the top of each child window It is possible to open legacy Pile and Pilset files in this v
17. the boundary between linear elastic zone and logarithmic yielding zone f the peak force of the soil spring w yield displacement of the soil spring c 1 0 to ensure gradient of function equals zero at f For the post peak degrading portion an exponential decay is assumed based on Siedel and Coronel 201 1 ed Nw VV fo fo 11 fo fag 1 exp 24 res where f is the force in soil spring for a post peak deformation of Aw in the soil spring Aw Is the total post peak deformation in the soil spring leading to a residual force f in the soil spring Pan is the minimum post peak force of the soil spring f is the peak force of the soil spring w is yield deformation of the soil spring The tip load curves are treated in a similar way to the shaft curves described above However there is no softening portion for the base as can be seen below Copyright Oasys 1997 2014 EN MM Pile Oasys Geo Suite for Windows Freak Force Prield Displacement Notension in base spring 2 2 2 1 4 API There are two different types of API curves for shaft e Sand The shaft curves in this case are essentially elastic plastic The user just needs to specify the yield displacement z to define the curve Copyright Oasys 1997 2014 Method of Analysis o4 Yield point Force Displacement e Clay For clay the program uses a set of multi linear curve
18. z mm Press lt TAB gt to start a new record z q qmas land x max 30 Y mas 1 0001 4 Disp Absolute Normalised Axial tip deflection z the deflection at the tip It can also be normalised by selecting the normalised radio button By default it is absolute Normalised tip stress q q the ratio of mobilised tip stress to maximum tip stress Copyright Oasys 1997 2014 5 15 Applied Loads amp Displacements Input Data 117 Each record in the Applied Loads amp Displacements table view consists of the following items Manual pls Applied Loads amp Displacements E B C BEE Depth below ground Prescribed soil level Applied load displacement mm n kN 9 0 00 1500 00 000 0 00 mm 0 00 Default 1 0 00 Y 2 12 00 20 00 E E 0 000 0 000 0 000 0 000 Enter depth below ground level Level Depth below ground level level depth at which the pressure is the specified Applied load downward positive and upward negative Prescribed soil displacement heave is defined as negative displacement and settlement as positive displacement i e soil moving upward negative and downward positive Note Prescribed soil displacement is only available for settlement calculations The data are specified at appropriate levels down the pile The data can be entered in any order the program internally arranges levels and interpo
19. 89 5 95 S tlement Dala EE TDI EE 91 5 5 Pile GOOMe IV a a A 92 90 1 Pile Properties caricia A N a ias 93 5 5 2 Pile Lengths ici in c indien eia A A diues e ERR I EU I n RUNE c id 95 5 6 3 Pile Cross section DIMENSIONS eren rennen nennen nnn RRE RR 96 5 6 4 Under reaM TO TTE A AS 97 SNAMB i re 98 5 7 1 Undrained Materials 5s oca eth en te edad nnmnnn nnmnnn mannanna nnna 98 5 7 2 Drained Materials na E TS 100 5B ell PTOI a e OI A E E 103 5 9 GrOURGW ate lk uie A LIT uL de Cede dd 105 5 10 Soil Profiles Groundwater Map e eeeeieeeeieeeeee eene nenne nnne nnne nenne nnne nnne nn 107 ST BRECUVE Siess Profiles ia ETT 107 912 DPEAEeus rte 108 9 43 bz CURVE Dita 108 DIS WAS tic PAS MO A A O Qe P idas 109 2X Edere At id 109 13 36 hintand Poos ci E PME 110 A LA O RN 111 AAA A DDA E ETE 111 SE 19 0User SpecilOd RIETI o LI I a e aE eSEE 112 5 14 Np Load Curve Dala iconos UE E 2c ep uo e Co ps RAE DEI DA MER DEN DONE IDEE IS IAE NOPR EID I senses DG ISR RIO ARRA NOSE 112 BAA BAS tC Pl aS HO sies ico cade A AA vede Bab saca aoro rosa luc vec dapat vate seus E En dress volvi goods 113 5142Chin and Poulos e eee ee 113 MEE Boferul rM 114 Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows DURIA sEusenniccnnRuRNUE MU MEII UD H E
20. ADAM NEUE uU UU ceeceecectevas 115 5 14 5 V Tay VOR UOTA ios 115 25 14 GUS ET Specia d oo eat a Les ib 116 5 15 Applied Loads amp Displacements is 117 5 16 Displacement Had cis 119 5 17 Convergence Control Dala codes 120 5 16 Thermal and Cyclic EOaUIDQ ii ias 121 6 Staged Analysis 122 7 Output 124 fal Analysasand Bata CHECKING isa Exe E Aaa 124 FEE Tapular Outpt tT M 125 7 3 Graphical OUUU Aia 128 8 List of References 131 8 1 REICFENCES oot imp Is oe atte a Undo cine cide est ea io 131 9 Manual Example 132 ACID c 132 10Brief Technical Description 132 QUSE PHO ote 132 Index 134 Copyright Oasys 1997 2014 About Pile 1 About Pile 1 1 General Program Description Oasys Pile Pile load capacity and Settlement Oasys Pile calculates the vertical load carrying capacities and vertical settlements of a range of individual piles in a layered soil deposit The theory is based on both conventional and new methods for drained frictional and undrained cohesive soils Settlements are calculated for solid circular sections without under ream 1 2 Program Features The main features of Oasys Pile are summarised below Capacity analysis settlement analysis or both can be performed for a range of pile lengths and cross sections in different soil profiles Settlements are calculated for only solid circular cross sections without under ream The soil is specified in layers Each layer is set to be
21. Bust intra Caine lt Qr then Quae 7 Gai Qsiinc else Osa Gig where Q yy internal skin friction at a pile embedment depth d1 Qu yo nternal skin friction at a pile embedment depth d2 Quer mt g1 Cumulative internal negative skin friction accumulated over depth d1 ee incremental internal skin friction between depths d1 and d2 Quo m bearing capacity at depth d2 over the plug area alone excluding the wall area However if the incremental layer contributes to negative skin friction If Qi ai Qst Int di j Qi inc lt Qh d2 then Qu et Int d2 Qst Int di a Qi inc where Copyright Oasys 1997 2014 EM Pile Oasys Geo Suite for Windows Qia internal skin friction at a pile embedment depth d1 Quigo internal skin friction at a pile embedment depth d2 Q st Int di cumulative internal negative skin friction accumulated over depth d1 Qst Int d2 cumulative internal negative skin friction accumulated over depth d2 Qui inc incremental internal skin friction between depths d1 and d2 Qh a2 bearing capacity at depth d2 over the plug area alone excluding the wall area Note e The reported unplugged capacity from case 2 will be the minimum of the capacities from case 1 and case 2 e For piles in tension Q w Quer ext Qu O 2 1 3 4 Allowable Capacity Working Load Approach Traditionally global factors of safety are applied to the ultimate end bearing capacity and the skin friction to take into
22. Method of Analysis NON Displacement No tension in base spring 2 2 2 1 3 Logarithmic For logarithmic shaft curves the initial curve is consists of three distinct zones e Linear elastic zone till yield e Logarithmic yielding zone e Exponential degrading zone Copyright O Oasys 1997 2014 NON Pile Oasys Geo Suite for Windows F Peak E Force 4 Frisia Displacement For the linear elastic zone the stiffness of the soil spring is given by 2x 1 8 xr In To Kai where E Young s modulus of soil layer at the location of soil spring Al length of the interaction area corresponding to the soil spring This is the average length of elements connected to the node at the location of soil spring n Poisson s ratio of the soil layer at the location of soil spring rj radius of the pile r distance from the axis of pile at which the shear stresses are negligible For the logarithmic yielding zone the following equation for spring force f is used based on Puzrin amp Burland 1996 Puzrin amp Shiran 2000 Copyright Oasys 1997 2014 Method of Analysis Wow s zx e jy ie al f f t w w 1 a fin Wy Wy Ej uu de X 1 tao al B cilc x llnii c x d pe 1 u Xr 1 E xp intl xia where f force in the soil spring for a deformation w in it f yield force of the soil spring It is expressed as a fraction amp of the peak force and marks
23. Oasys 1997 2014 Method of Analysis e then fi is replaced with TO and the equation becomes Wy i 2 T AWoLi 1 AW 1 0 Cycle 0 Cycle 1 Force Cycle 2 B Reloading point Yield point Displacement The above equations are used for both pre peak and post peak cycles by replacing the post peak term with a pre peak term for the cycle in question The corresponding values for pre peak instead of post peak behavour are Wo 2 instead of We io AW io instead of Aw Aw and for pre peak displacement on load cycle i 2 while for pre peak displacement pl i 2 fnax 7 Mstead of f on load cycle i 1 Aw _ Should be used instead of Aw Post peak degradation On every cycle peak force degradation to minimum post peak force force occurs after the spring is loaded beyond peak force The degradation is of similar form to the monotonic post peak degradation exponential curve however the irreversible displacements that have occurred over previous cycles must be accounted for in the degradation curve of the current cycle The displacement from peak to minimum force on the current cycle Aw is reduced by the sum of the accumulated irreversible displacements ew _ over and above the monotonic irreversible displacement required to reach peak force for the first time Wom AW pas Aw ZAw aLi i AW yim The form of the equation for calculating the post peak force sim
24. account uncertainties in soil properties loads installation method and the calculation method and also to limit settlement Solid Piles The factored load is termed the allowable or working load For solid piles this is defined as the lesser of P Q Q F 0 Py Q F QV F Quer P Q F o Eun Flowable Ap where Q skin friction cumulative positive skin friction Que negative skin friction Q end bearing capacity of the solid pile A cross sectional area of pile flowable allowable stress in pile at working load compression E global factor applied to the calculated ultimate bearing capacity ge partial factor applied to the ultimate skin friction component E partial factor applied to the ultimate end bearing component F gt factor applied to the ultimate skin friction component Note It is not mandatory to select all combinations The same applies for the tension case and for hollow piles Copyright Oasys 1997 2014 Method of Analysis In tension Q and Q er are both zero and the criteria are P q Q Is Pa Ftowable Ap Note The corresponding parameters F and f for the tension case have to be explicitly allowable specified Hollow piles For hollow piles however we have the following criteria to consider owing to the plugged condition of the pile Pa Q Q Q F Q t e Q sti Py Q Qi Q os estu lada Pj Q Q Quo Fs Q st e
25. brtvo tes o tecub Venter Reset oue etaotrs pun tudo faber race si esl ebat Eo 14 2 1 3 3 Unplugged Capac IY sess ades foem Sin ada tea om octo cca ias 14 2 1 3 4 Allowable Capacity Working Load Approach cccconnnicccoconccccononccccononananononononnnnnnnnnccnranannnn nono rnnnennnnnnnnns 16 2 1 3 5 Design Resistance Limit State APpProach ccccceccceeeceeeeeeeeeeeeeeeeseeeeeeeseeeeeeeeeeeseeeseeeeeeeseeeseeseeeeseeeeeeess 18 2196 Code Bas ed a e a a a a 19 e EN o an UE A AAEN 20 A Pr s SKIN Meton COME ATON r Tp 20 2 1 4 2 Hid Bearing COMPUTO iii A E p p aed c Qn A ATIS TA 21 2 1 4 2 1 BerezantzevilVletlioQ duas ceco roii Beo le raul 21 Pn M moro BONO MENO TH H s 24 2 2 lt DSOTUEMEING err Ret 25 22 1 Mindlin ADDFOGCI ci eh ac Pss itti dude cu cd cie i e ai vec Sere S Gr cios 25 2 2 A MMCORY OMAIANY S Sus koc te odctp as A Eee Y RETE eden Do bae eU E eL das nets leanne tae fecousu ELLE Ux P etu TaU Cla Sa urs 25 2 2 1 2 Integration of Miridlis eduallor Ssss ass esbevs ey eme aus dodo eraat REA Ux pe Seales pu orc Eko Ora Rd E ca eECYO ERE EE dU UR ND UTR SEN Ea RE RUE 31 2213 HIE SHItness MAT ici a aida cU Enea out ias 36 222 E E GUNNS A A e 40 222 Job Sfness MAD auda bird dcir N 40 22211 Elas c Hastie CUNO Srnci SE a 41 2 2 2 1 2 Hyperbolie CUV CS ana E lic a 43 2 2 241 3 Eogan ea aa 45 22
26. drained frictional or undrained cohesive and appropriate strength parameters are specified Maximum values can be set for ultimate soil shaft friction stress and end bearing stress within each layer Levels may be specified as e depth below ground level or e elevation above ordnance datum OD Porewater pressures within the soil deposit can be set to hydrostatic or piezometric Pile capacities may be calculated for a range of pile lengths and a range of cross section types such as circular square and H section The circular and square cross sections may be hollow or solid whereas the H section is only solid Under reams or enlarged bases may be specified Pile settlements may be calculated for a range of pile lengths and a range of solid circular cross sections without under ream There are three approaches available to calculate the capacity of the pile e working load approach e limit state approach and e code based approach The graphical output depicts the variation of different pile capacities such as shaft resistance end bearing total bearing with pile depth and settlements of pile or soil This may be exported in WMF format The text output contains the tabular representation of the input data and results They may be exported to CSV format Legacy Pile and Pilset files may be read Limiting shaft skin friction is now calculated from the material properties so the reading of limiting shaft skin friction from lega
27. is required to enter a series of points as discussed above However the curve is not extended into the tension region e base spring does not take tension Copyright O Oasys 1997 2014 Method of Analysis 55 Displacement Notension in base spring 2 2 2 2 Pile Stiffness Matrix The pile is modelled as a series of axial elements i e one dimensional elements where the Stiffness matrix of each element is given by AE L AE L AE L AEJ L where A is the area of the element E is the Young s modulus of the material L is the element length The total Pile stiffness matrix of a pile with n elements is of size n 1 x n 1 and is given by Copyright Oasys 1997 2014 o5 Pile Oasys Geo Suite for Windows EL kis 0 0 0 0 0 0 0 0 0 kl kl ki E 0 0 0 0 0 0 0 0 0 ki ki kj E 0 0 0 0 0 0 0 0 0 ES k3 kh 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 n 0 0 0 0 0 0 0 0 0 kiki ki 0 0 0 0 0 0 0 0 0 kay 0 0 0 0 0 0 0 0 0 m 0 0 0 0 0 0 0 0 O kL 4RE RT 0 0 0 0 0 0 0 0 0 kr Et E where the superscript indicates the element number This Pile Stiffness Matrix is assembled with the Soil Stiffness Matrix and the resulting Global Stiffness Matrix is used to calculate the displacements 2 2 2 3 Effect of Cyclic Loading There are currently 3 different ways in which the cyclic loading is handled in the program for t z and tip load curves e Default behaviour Elastic plastic User defined Vijayvergiya and API c
28. layer Cu Botton is ignored Material Properties Copyright Oasys 1997 2014 Output 125 7 2 Tabular Output Tabulated output is accessible from the View menu the Gateway or the Pile toolbar This output may include input data and results if an analysis has been performed rhe Edit View Data Analysis Output Took Window Help DemlX alsBledeea Settlement analysis i Drai i Analysis Options Datum type Elevation based Effective stress profile Calculated pod Rigid boundary level 200 000 mOD Heres Files 1 Poisson s ratio of soil 0 250000 E E Na Phi Curves 1 Young s modulus of soil above toe level of pile 20000 0 kPa Po Nonlinear Curve 1 3 Young s modulus of soil below toe level of pile 40000 0 kPa t z Curve Data Number of pile elements 10 ii La Elastic Plastic Increment type Loads only i Number of load increments 1000 Increment results would be printed once every 1000 increments i Include effect of soil above pile base in base displacement Yes PO calculation Pile Properties Elastic Plastic P Chin amp Poulos 1991 Pile type Solid i Empirical API 1993 Pile cross section Circular Be Under ream No E fi Use different values of Young s modulus for No i compression and tension Young s modulus of pile 20 0000E 6 kPa Calculation profile Single Copyright Oasys 1997 2014 MES Pile Oasys Geo Sui
29. numerical means It is assumed that the influence of the pile base on the displacement of i is negligible hence 20 Mirror Image Method The element id is similar to li but with z 2H h cand z 2H h c 2 2 1 3 Pile Stiffness Matrix In calculating the displacement of the pile itself only axial compression of the pile is considered O c O 57 dz Consider the vertical equilibrium of a small element of the pile An equilibrium equation can be derived as pud 4p z A Rad a C4 The axial strain of the element is approximately Copyright Oasys 1997 2014 Method of Analysis p a 02 EP therefore p 4p 1 z d EPR This is solved by using finite difference method which may be approximately expressed by the Taylor Expansion Difference Formulations i For2 lt ix n 1 Pi 1 pi p JP 6 p Pi Pit dp tf 6 p Pi 1 2Pit Pisa therefore Copyright Oasys 1997 2014 NE Pile Oasys Geo Suite for Windows p gon Pa 20s P ii For i 1 QR Sp 8 R Py P1 op r_ Pi Py __ Fy LEE g AE F i Pit tee Pi p3 2 pep Pa i g Pi iii Fori n TF pir 7 Pa Pn 28Pn s SO Or SO Pn 2 Pn 26p 467p l6pg Pn 2 15p 108p Pn 1 Pn Op 1 267 1 Ll Pa 5 Un Pn O Pa 1693 Pn 2 15p 10 p Peza 1 562 p IL Pn 526 0 4 p n 2
30. particular stage such as after several cycles of pre peak loading and unloading the program reduces the peak force in the spring in a similar manner to post peak monotonic exponential decay This is based on foi fo MUS fJ E e 24 eerpti s reum tees In this equation the subscript i denotes the half cycle number Two consecutive half cycles correspond to a change in the direction of increasing force i e from increasing force to decreasing force or vice versa EAW i is the cumulative absolute irreversible displacement till the i 1 half cycle AW pl m is the monotonic irreversible displacement to the peak force It is important to note that Copyright Oasys 1997 2014 Method of Analysis this excludes elastic displacement to peak force Force Cycle 0 Cycle 1 E Unloading point 6 Yield point Displacement Also the yield force in a particular stage half cycle depends on the spring force f in the previous two half cycles i e one tension stage and a compression stage dant Dansi iT 0 5 1 E gn EM with the requirement that the yield force calculated using the above equation should not be below cu peak In order to maintain a similar shape of logarithmic function during reloading and subsequent unloading stages the displacement from yield force to peak force is a function of the amount by which the yield force has reduced from the maximum force as well as the irreversib
31. profile of gs across the layer either calculated or user specified b Get the value of No either user specified or Berezantzev Method or Bolton method c Get the bearing pressure q from q N 0 2 Get the cross sectional area of the pile base pile wall and soil plug as appropriate 3 compute end bearing capacity of the pile 2 1 4 2 1 Berezantzev Method The following steps are implemented in the Nq calculation algorithm when Berezantzev method is selected in the Effective stress table view i Berezantzev A B Curves These curves are based on the paper by Berezantzev et al 1961 This calculation algorithm is performed when the standard Berezantzev Ak Bk Curves option is selected in the N Phi curve field of the Effective stress table view Copyright Oasys 1997 2014 22 Pile Oasys Geo Suite for Windows 1 Get the user specified value of drained friction angle for the layer at the location of pile toe depth 2 Get the user specified value of friction angle 4 corresponding to the soil of overburden Note When there are multiple soil layers around the shaft the program uses the user specified of the layer at the location of pile toe depth as the equivalent q of the whole overburden soil around the pile shaft 3 From the given value interpolate extrapolate the value of coefficients A and B from the 9 A and B graphs respectively 4 The values of A and B in the program
32. specifying a value of y less than 10kN m Copyright Oasys 1997 2014 Input Data 107 For piezometric profiles the level depth and pressure at each known point must be entered If more than one data point is entered the program will assume that the points represent piezometers and the ground water pressure will be interpolated vertically between the specified points Below the lowest point groundwater pressure will be assumed to extend hydrostatically 5 10 Soil Profiles Groundwater Map The groundwater profile needs to be specified for each soil profile using this table view CudeTests Undrained pls Soil profiles groundwater map B Groundwater Hane OO emer oreundweter Profile 2 Mone The number of records in this table view is fixed and is the same as the number of soil profiles 5 11 Effective Stress Profiles A separate effective stress profile needs to be specified for each soil profile Each tab corresponds to one soil profile The tabs in this table view cannot be edited as there is a one to one relation between this table view and the Soil Profiles table view Each record in the Effective Stress Profiles table view consists of the following items Codelests Ener VENENOS Effective Stress Profiles L stress stress Layer Material kPa kPa Top of layer Base oflayer Top of layer Base oflayer Defaults 0 00 0 00 0 00 0 00 0 00 0 00 0 00 0 00
33. stress profile to be used by the program in calculating the pile capacity are specified Datum Information There are two choices for datum e Depth below Ground Level e Elevation above Ordnance Datum Copyright Oasys 1997 2014 input Data e1 5 4 Capacity Data The following data needs to be entered to specify the type of capacity calculations to be carried out Capacity Calculations Calculation Method CO Working Load Design Resistance 2 Code Based Design Code Country Code 15 2811 w Mote 1 In Working Load approach user defined partial global Factors are applied to skin Friction and end bearing components Negative skin Friction is included in computation of allowable bearing capacity 2 In Design Resistance approach user defined partialfiglobal Factors are still applied to skin Friction and bearing components However user needs to specify material and model Factors too Negative skin Friction is excluded in the calculation of design resistance 3 In Code Based approach Fos are taken directly From the code They are not defined by the user unlike the above two methods Calculation Method Copyright Oasys 1997 2014 a Pile Oasys Geo Suite for Windows There are three options available e Working Load e Design Resistance e Code based In this method the explicit design code has to be specified Presently EC7 No National Annex EC7 United Kingdom and IS 2911 are availa
34. terms are for the shaft and base springs are dependent on the type of t z curves The types of t z curves and tip load supported by the program are Elastic Plastic Randolph and Wroth Hyperbolic Chin amp Poulos Logarithmic API Empirical Vijayvergiya and User specified in which stiffness values are calculated directly from stress displacement curves given by the user Chin and Poulos Tip Load Curves e Unloading curve Z Z a Pom a KETILA 7 Copyright Oasys 1997 2014 Method of Analysis EN where R r fa RL 2 z is the displacement at load reversal p corresponds to the load reversal point e Reloading curve zo Porto i ke 1 pr where R Bp 7T 2R 6 2 2 2 1 1 Elastic Plastic Curves These curves are characterized by a constant stiffness till yield After yield the stiffness is zero This is common to both the shaft and base curves It is also important to note that the base curves are limited to compression only They do not carry tension Typical elastic plastic t z curve is shown below Copyright Oasys 1997 2014 v Pile Oasys Geo Suite for Windows Yield point Force Displacement Typical elastic plastic tip load load curve is shown below Copyright Oasys 1997 2014 Method of Analysis a3 Yield point Force Displacement Notension in base spring 2 2 2 1 2 Hyperbolic Curves These are based on Chin amp
35. the unplugged capacity auto plugged plot T Ultimate load compression toggles the ultimate load compression plot p Working load compression toggles the working load compression plot E Design load compression toggles the design load compression plot R4 Ultimate load tension toggles the ultimate load tension plot p Working load tension toggles the working load tension plot po Design load tension toggles the design load tension plot Settlement ER Limiting Shaft Skin Friction toggles the limiting shaft skin friction plot if Shaft Skin Friction toggles the shaft skin friction plot H Pile Stress toggles the pile stress plot Pile Soil Displacement toggles the displacements for pile or soil E Envelope toggles whether or not envelope of results is plotted for cyclic loading sub stages Drop lists above the Graphical Output View allow selection of capacity and settlement results according to selected soil profiles pile cross sections pile lengths applied load displacement increments and sub stages The plot can be exported in WMF format via the Graphics Save image gt Save WMF menu item Copyright Oasys 1997 2014 List of References 131 8 List of References 8 1 References API 1993 Recommended Practice for Planning Designing and Constructing Fixed Offshore Platforms LRFD API Recommended practice 2A LRFD 15t Edition Bailie P 2013 An investigation into the cyclic res
36. value of the material proportion of peak force which is yield force Ww displacement at peak force peak Copyright Oasys 1997 2014 Input Data 115 5 14 4 API API Tip Load Curve is a standard curve and is non editable Normalized axial tip a deflection z D Normalised tip stress Q Qb m a aad kaa Eoad band Enni n a na o 2 2 S n 2 a 2 eaeimseleiajao apo oajojo 5 5 Eia e a ux 7 e in EE a a 1 m E a 0 00 0 00 0 00 5 0 07 0 10 0 13 0 15 0 17 0 20 0 23 0 25 Normalised axial tip deflection z D Cell A 1 z D 00b Grid lt max D 250 41 Y max 1 000 4 Disp Absolute Normalised 5 14 5 Vijayvergiya Each record in the Vijayvergiya t z Curves table view consists of the following items Ca A mm MViayvergiva Tip Load H 1000 000 Vijayvergiya Tip Load 1 300 000 lt Cell B 1 Description the name of the curve Z the movement required to mobilise maximum tip resistance This value is often around 0 25 Copyright Oasys 1997 2014 116 Pile Oasys Geo Suite for Windows inches for sands 5 14 6 User Specified Each record in the User Specified t z Curves table view consists of the following items E temp2000 pls User Spec Tip Load Curves Ex User Spec Tip Load Add Curve be Cr Cr gu a i wn a u a m z o 0 00 0 00 0 00 20 30 40 50 60 370 0 90 Axial tip deflection
37. 2 APRE re doter c EU iE M e e 48 2 2 2 1 5 Emperical cV illa V Velgly aea a Erde ERE E E Eo pe icu RERO E A EdP ER DE YD ED EU dU OR NB UU Ee t ERE 51 22 2 6 USSr delled nasci oat dni eie da ud ina 53 2 2 2 2 Hle SUtness MalbbGssusucuo s ivre Nba 55 Copyright Oasys 1997 2014 Contents 2 2 2 9 BHOCLtoOh GyClC EOAGING coo on cta codice i Ee que opi co RM d E HERE AEDU Pa EA HARRIS ENS GR ORT teeta EA E 56 2 2 2 9 O Beliaviouf setti eei eerie cede Ee ce vo t Fro tet eb vetere aed Ut vec pte debe e bend wick tee eae Sues bated e TTE 56 22232 MPa osa else iced d e ed ah ast testo e ad uA E E 62 222033 Ogame UT 64 2 2 3 Different Young s Modulus for Compression and tension sees eese eeeeee eene nnne nnns 71 2 2 4 Staged Analysis and Cyclic Loading iria a anaana naiai a Raiana aaa 72 3 Opening the Program 73 3 1 dntranet L Mk and Emails 2 oer ees ex cues ovS eeu r tas 75 4 Assembling Data 76 5 Input Data 77 cx EE UU qm Enc 78 De led Titles window BRIM ApS ciii apa echas ced as 79 PME NER ENSE TONES MESSER ITEMS SOR DONNE AU E ERNEUT NOR PENES MARO URINE 79 53 ANAIS OPTIONS I Tc T DN DD c 80 54 Capacity Dala mme RN 81 94 1 W rking OA e EI I A e aaa 83 94 2 Design RESISTANCE ina aA a e E A AAA A 85 5 4 3 ECT No National A ts 86 544 ECT United KINGdOM sisi A dio 87 TO NND E a a aa Eaha eaaa
38. 2al scel 266 aeS o 366 410 456 505 556 ell 658 Tues c 790 555 sid 9 393 S513 a52 Gad 993 30 az 46 3 17 17 ag dz 46 dz ao 15 au 33 1067 2 H L HH HH HR HR RH H H HR RB HR HR H HR RH poc C 6C CO The lists of tabulated output can be highlighted and then copied to the clipboard and pasted into most Microsoft Windows type applications e g Microsoft Word or Excel The output can also be directly exported to various text or HTML formats by choosing File Export from the program menu Sign conventions are as follows Copyright Oasys 1997 2014 Applied load downward positive and upward negative Pile stress compression positive and tension negative Base pressure downwards positive and upward negative Displacements negative movement is upwards e g soil heave and positive is downwards e g pile or soil settlements Pile Oasys Geo Suite for Windows 7 3 Graphical Output Graphical output of data and results is accessed via the View menu the Gateway or the Pile toolbar EF Pile 19 5 Settlement cale Sqpls Y Ww A UU Ww 9 File Edit Data Analysis Output Tools Window Help a g z Toolbar Mc EF y v Status Bar v Gateway S Input Graphical Output y Pile Titles Title Tabular Output Ey Settlement calc Sq pls Stage Operations Analysis Options Settlement calc Sq pls Tabular Output i Capacity Data
39. 7 2014 Input Data 109 5 13 1 Elastic Plastic Each record in the Elastic Plastic t z Curves table view consists of the following items EEE RT pls Elastic Plastic t z Curves Top H ERSTES i ElsPlastzi 0 15000000 C 5 pu Cell A 1 Description the name of the curve Young s modulus Top the Young s modulus at top of the soil layer Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio of the material r the radial distance at which the shear stress in the soil becomes negligible 5 13 2 Logarithmic Each record in the Logarithmic t z Curves table view consists of the following items Pilel TL t z curves amp im BENE NNUS REN EET UE A ee PA WITN s Young s modulus E E Poisson s Shaft boundary Description ratio V radius ra mm mm A 0 00 0 0 Cell A 1 Description the name of the curve Young s modulus E Top the Young s modulus at top of the soil layer Copyright Oasys 1997 2014 wo Pile Oasys Geo Suite for Windows Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio value of the material r the radial distance at which the shear stress in the soil becomes negligible proportion of peak force which is yield force Ww displacement at peak force peak sott l actio
40. AI1 CI 02 O DAZ Pile Type CO Driven Bored Design Procedure 5 Model pile Alternative method Mumber of profiles Model Factor Code specific data should be specified in this dialog Either of DA1 DA2 and DAS can be specified Further either model pile procedure or alternate procedure can be specified Copyright Oasys 1997 2014 Input Data The check box regarding stiffness is active only when the model pile procedure is selected The Number of profiles refers to number of soil profiles and is read only 5 4 4 EC7 United Kingdom Eurocode U K Design Approach 2DA1 C1 C2 Pile Type Driven CO Bored Model Factor Partial Factors On Negative Skin Friction x Set 41 partial Factor Set AZ partial Factor Serviceability is verified by load bests preliminary working carried aut an more than 1 of constructed piles to loads nat less than 1 5 times the representative load Far which they are designed a Resistance is verified by a maintained load test taken to the calculated unfactored ultimate resistance Print detailed output of capacities From all combinations In this case only DA1 is available The model factor is read only and depends on whether the the second check box shown above is selected or not Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows Also partial factors on negative skin friction for the two action factor sets A1 and A2 respectively
41. ATO Ma 2 00 LMG Upper Ma 10 00 LMG Upnor No 11 50 LMG_Upnor Reduced Mo 12 50 THS No H t Soil Profile 1 42 Soil Profi lt Enter depth below ground level Level at Top Depth below ground level level of the top of each layer according to the datum chosen The levels must be entered in decreasing order if datum information is elevation in Analysis options dialog The depths must be entered in increasing order if datum information is depths in Analysis options dialog Material the soil material that is present in the layer Copyright Oasys 1997 2014 104 Pile Oasys Geo Suite for Windows Contribute to Negative Skin Friction whether the layer contributes to negative skin friction This was material specific in earlier versions of Pile it is now layer specific The material properties can be defined when entering new layer data using the new material wizard This wizard can be invoked by clicking the wizard toolbar button Pile 19 4 Pile1 File Edit View Data Analysis Tools Window Help i HE amp DPM XHOSA ees P bel Ez OQ CA Aa a Input Titles Units Analysis Options Capacity Data Settlement Data Pile Properties Material Properties Undrained Materials Drained Materials Soil Profiles Groundwater Soil Profile Groundwater Map Effective Stress Profiles 1 Nq Phi Curves Applied Loads amp Displacements Displacement Ri adii Converg
42. B Base Diameter 97 Bearing Capacity 12 Bearing Pressure 21 Bearing Resistance 18 Berezantzev 10 21 100 108 Berezantzev Method 21 Beta 9 100 Beta Method 9 100 Bitmap 79 Bolton 10 21 100 108 Bolton Method 24 C Calculation Options 80 Calculation Procedure 20 Cays 8 Characteristic Base Resistance 18 Characteristic Shaft Resistance 18 Checking 124 Circular 93 Cohesive 1 132 Company Info 79 Components of the User Interface 2 Critical State Angle of Friction 10 Cross section 1 93 Cross section Dimensions 96 CSV 1 125 132 Cumulative Capacity 9 D Data Input Scrrens 73 Deep Strip Footing 10 Delta 100 Depth 1 Design Action 18 Design Base Resistance 18 Design Options 80 Design Shaft Resistance 18 Dilatancy 10 Drained 1 132 Drained Friction Angle 10 21 Drained Undrained 76 E Earth Pressure 9 20 100 Earth Pressure Method 9 EC7 18 Effective Stress 98 100 107 Effective Stress Approach 9 10 Effective Stress Profiles 107 Elevation 1 Email 75 Embedment 10 End Bearing 10 12 16 20 End Bearing Capacity 21 End Bearing Computation 21 Examine 124 Example 132 Export 125 External 20 External Side Width 96 E Factored Load 16 Factors of Safety 16 Copyright O Oasys 1997 2014 Index 135 Frew Toolbar 2 Load 1 132 Friction Angle 100 Load Cases 18 Frictional 1 132 M G Manual 132 Gateway 2 Mass Data 92 General 7 Mass Ground Connections 98 General P
43. Layer3 20 00 260 00 260 00 Alpha Specified 0 45 Yes 200 00 lt gt All A General A Friction A Bearing Enter material name b a HA AO AA Y ES Skin IN data End bearing data a CHEN NETTE A Mini Tip load curve I D elu kPa kPa kPa A O LE ESE Nc Specified LR IS 200 00 Elas Plas t z 2 Nc Specified 200 00 Elas Plas t z 2 Nc Specified n Elas Plas Tip Load 1 Elas Plas Tip Load1 Material description brief descriptions for the material types can be entered here Bulk unit weight bulk unit weight of the soil layer Material factor for soil strength this factor that needs to be applied to cohesive strength or friction angle depending on the type of material When the Working load method is selected in the Analysis Options the Material factor for soil strength field is greyed out completely It is active only when the Design resistance method is chosen Soil strength Cu Top undrained shear strength of the total stress material at the top of the layer Bottom undrained shear strength of the total stress material at the bottom of the layer Copyright Oasys 1997 2014 Input Data o When the bottom most layer in the model is assigned a Total stress material the cohesion within the layer is assumed to be constant with value of cohesion specified at the top of the layer C Top The cohes
44. P y Qu Qu Fs1 OLE Quero Qu EN ES EQU ce iraou Pa z Q ie s Q Qu Fo 3 Qst e P Q IF eo Po flowable Ap where Q e external skin friction excluding negative skin friction Q internal skin friction excluding negative skin friction Quer external negative skin friction Qs Internal negative skin friction in this case the top of the internal soil at the same level as ground level G tradu internal negative skin friction in this case internal soil level changes with driven pile depth Q end bearing capacity of the hollow pile over the wall area Q riug bearing capacity of the plugged portion of the hollow pile excluding wall area A cross sectional area of pile f owape allowable stress in pile at working load a global factor applied to the calculated ultimate bearing capacity Eon partial factor applied to the ultimate skin friction component Copyright O Oasys 1997 2014 ow Pile Oasys Geo Suite for Windows gm partial factor applied to the ultimate end bearing component F gt factor applied to the ultimate skin friction component In tension Q Q ug Qist e and Q st i are all zero and there are just the following criteria Pa Qe IF so Pa Ftowable Ap Note The corresponding parameters F and f allowable for the tension case have to be explicitly specified 2 1 3 5 Design Resistance Limit State Approach In limit state codes it is usual to
45. Pile Version 19 5 Oasys Oasys Ltd 13 Fitzroy Street London W1T 4BQ Central Square Forth Street Newcastle Upon Tyne NE1 3PL Telephone 44 0 191 238 7559 Facsimile 44 0 191 238 7555 e mail oasyS arup com Website http www oasys software com Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows Copyright Oasys 1997 2014 All rights reserved No parts of this work may be reproduced in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the written permission of the publisher Products that are referred to in this document may be either trademarks and or registered trademarks of the respective owners The publisher and the author make no claim to these trademarks While every precaution has been taken in the preparation of this document the publisher and the author assume no responsibility for errors or omissions or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document This document has been created to provide a guide for the use of the software It does not provide engineering advice nor is ita substitute for t
46. aded End bearing Piles Geotechnique Volume 19 No 2 pp 285 300 Poulos H G and Davis E H 1980 Pile Foundation Analysis and Design Chapter 5 Series in Geotechnical Engineering T W Lambe and R V Whitman eds John Wiley and Sons Puzrin A M and Burland J B 1996 A logarithmic stress strain function for rocks and soils Geotechnique Vol 46 No 1 pp 157 164 Puzrin A M and Shiran A 2000 Effect of a Constitutive Relationship on Seismic Response of Soils Part I Constitutive Modeling of Cyclic Behaviour of Soils Soil Dynamics and Earthquake Engineering Vol 19 pp 305 318 Copyright Oasys 1997 2014 132 Pile Oasys Geo Suite for Windows 10 10 1 Randolph M F and Wroth C P 1978 Analysis of Deformation of Vertically Loaded Piles Journal of the Geotechnical Engineering Division ASCE 104 No 12 1978 pp 1465 1488 Randolph M and Gournevec M 2011 Offshore Geotechnical Engineering Taylor amp Francis ISBN 978 0 415 47744 4 Seidel M and Coronel M 2011 A new approach for assessing offshore piles subjected to cyclic axial loading geotechnik 34 2011 Timoshenko S and Goodier J 1970 Theory of Elasticity 3rd Edition McGraw Hill Vijayvergiya V N 1977 Load movement characteristics of Piles Proceedings Ports 77 ASCE Vol Il pp 269 286 Manual Example General The data input and results for the Pile manual examples are available in the Samples sub folder o
47. are calculated by the polynomial equations generated for the data points that are read from the graph Note In digitising the curve the lower bound values have been read the generated polynomial equations for A and B are given below ad a3 d Ak 0 00261719x 9 0300278x 4 130706 s 253 216 xla 1837 45 I 4 l E I A 54 0 0033242x 9 0363837x 9 15 1495x p 260 8 75 xigii 1955 20 Note For the above two equations the units of Y are in degrees 5 From the given and depth ratio depth width calculate the value of a which is given by the following equation a E 2x flap Taa N PI pis Bep 5 Oa where A 2 tan D x tan ae Copyright Oasys 1997 2014 Method of Analysis 23 tan _ tan a Pr 5 4 2 f g xr Q n i2 Als t S2 2 E oun J AZ m tan 2 where R radius of the pile Copyright Oasys 1997 2014 a Pile Oasys Geo Suite for Windows D depth of the pile toe B diameter of the pile angle of friction of the soil layer at the pile base p angle of friction of the soil layer around the pile shaft Note For all the equations related to the calculation of o above the units of and are in radians Also in the Berezantzev 1961 paper the value of a is given in a table as a function of D B and dy alone The Y term does not seem to be considered when evaluating OL But in the equation ab
48. assess the ultimate limit state ULS for one or more combinations of factored applied loads and material properties Additional factors may be applied relating to the pile type and calculation method In EC7 terms the design action based on factored loads is compared with the design bearing resistance calculated using factored soil parameters and other related factors Different factors are used appropriate to one or more load cases Other codes use a similar approach The design bearing resistance in compression is the minimum of Ra Py Yo Rek YI ra Ry Ra Rok Yra where R bk characteristic base resistance x characteristic shaft resistance Y and y base and shaft resistance factors respectively y total resistance factor Yay Model factor compression Only one of the above two combinations can be used depending on the code For example for EC7 calculations where shaft and base resistances are evaluated separately only the first equation is applicable For solid piles the above definitions are straightforward However for hollow piles in compression there are three conditions to be considered Unplugged condition internal soil level remains at ground level e R is obtained by calculating bearing capacity only over the wall area e R is obtained by adding the contributions of external skin friction and internal skin friction assuming the internal soil level remains at ground level Cop
49. atic or piezometric pressure in the Groundwater table view Multiple Groundwater tables can be defined The Groundwater table view is accessible by double clicking Groundwater in the Gateway or via Data Groundwater on the program menu Associate the groundwater data tables with soil profiles using the Soil Profile Groundwater Table Map This can also be accessed from the gateway 10 If any custom stress profiles need to be used specify such user defined effective Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows 11 12 13 14 15 16 17 18 19 stress profiles in the Effective Stress Profiles table view At least one soil layer should be defined in order to access this table view The Effective Stress Profiles table view is accessible by double clicking Effective otress Profiles in the Gateway or va Effective Stress Profiles on the program menu opecify user defined Nq Phi curves in the Nq Phi curves tabbed table view This table view is accessible when capacity analysis is selected in Analysis Options dialog The Nq Phi curves tabbed table view is accessible by double clicking Nq Phi curves in the Gateway or va Data Nq Phi curves on the program menu opecify applied loads and prescribed displacements in the Applied Loads amp Displacements table view This table view is accessible when settlement analysis is selected in the Analysis Options dialog The Applied Loads amp Di
50. ber of elements and Pile Stiffness is calculated for each element Copyright Oasys 1997 2014 NON Pile Oasys Geo Suite for Windows Number of increments the load is applied in this number of equal increments Increment type i e whether load alone is incremented the applied displacement alone is incremented or both Increasing the increments helps to reduce any incompatibilities between relative displacements at the pile soil interface and the mobilised skin friction The rate at which the results from various increments need to be printed e g one in every 10 increments can be specified Irrespective of the frequency specified the program always prints the last increment 5 6 Pile Geometry Pile Geometry contains information regarding the type of pile the length of the pile cross section and under ream dimensions Copyright Oasys 1997 2014 input Data 99 5 6 1 Pile Properties The Pile Properties dialog presents the following input data Pile Properties Pile cross section Young s modulus Use different values for compression and tension Compression 2e 007 kPa 28007 Linear coefficient of thermal expansion le 5 0 3 Underteams Solid only 0 With underream Without underream File head 5 Free Fixed Notes Settlements are calculated for solid circular square without underream sections only Linear coefficient of thermal expansion and pile head condition are considered only
51. ble For theory about each of the above approaches refer the topics Working Load Approach Limit State Approach and Code Based Copyright Oasys 1997 2014 input Data 63 5 4 1 Working Load The following factors of safety must be specified Working Load Compression Calculate compressive capacity Global Fos Use global Fos criterion Global Factor on ultimate capacity Pg Partial FoS Use partial FoS criterion Partial Factor an ultimate skin Friction F1 Partial Factor an ultimate end bearing Fb Shark Fos Use shaft Fos criterion Factor applied to ultimate skin Friction Fs2 1 1000000236 Limiting pile stress Use limiting pile stress criterion Limiting pile material stress at working load lo kPa Tension Calculate tensile capacity Shaft Fas Use shaft Fos criterion Factor applied to ultimate skin Friction Fsz Limiting pile stress Use limiting pile stress criterion Limiting pile material stress at working load lo kPa In this approach the following factors need to be specified Global factor on ultimate capacity Copyright Oasys 1997 2014 NOS Pile Oasys Geo Suite for Windows Partial factor on ultimate skin friction Partial factor on end bearing Factor applied to ultimate skin friction In the working load option at least one of the following combinations should be selected global factor of safety on total bearing capacity partial factors of safety on shaft skin fr
52. cement z the shaft displacement This can also be normalised by selecting the normalised radio button By default it is absolute Normalised shaft shear stress t tmax the ratio of mobilised shear stress to maximum shear stress 5 14 Tip Load Curve Data There are 6 types of tip load curves supported by the program The following sections cover these options in detail Copyright Oasys 1997 2014 Input Data 113 5 14 1 Elastic Plastic Each record in the Elastic Plastic Tip Load Curves table view consists of the following items EE MB pls Elastic Plastic T Curves AA Sa Ss i s modulus Poisson s ratio Base curve coefficient T ES Elas Plas Tip Load H 0 000 0 000 0 300 Elas Plas Tip Load 1 15000 000 0 000 0 300 EIN o 3 0 Cell E 0 Description the name of the curve Young s modulus Top the Young s modulus at top of the soil layer Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio value of the material the base curve coefficient which allows for the depth of the pile base below the surface 5 14 2 Chin and Poulos Each record in the Chin and Poulos Tip Load Curves table view consists of the following items EE A pls Chin Poulos tip load curves o a Hyperbolic curve Unloading curve Reloading curve Degradation Top v fitting constant Rfb fitting constant Ry fitting cons
53. ction types Copyright Oasys 1997 2014 Brief Technical Description 133 such as circular square and H section The circular and square cross sections may be hollow or solid whereas the H section is only solid Under reams or enlarged bases may be specified Pile settlements may be calculated for a range of pile lengths and a range of solid circular cross sections without under ream There are two approaches available to calculate the capacity of the pile working load approach and limit state approach The graphical output depicts the variation of different pile capacities such as shaft resistance end bearing total bearing with pile depth and settlements of pile or soil This may be exported in WMF format The text output contains the tabular representation of the input data and results They may be exported to CSV format Legacy Pile and Pilset files may be read Limiting shaft skin friction is calculated from the material properties so the reading of limiting shaft skin friction from legacy Pilset files is ignored results in CSV format Copyright Oasys 1997 2014 MO Pile Oasys Geo Suite for Windows Index A Adhesion 8 Allowable Working Load 18 Alpha 98 Analysis 124 Analysis and Data Checking 124 Analysis Options 80 API 8 20 Assembling Data 76 Average External Skin Friction 7 Average Flange Thickness 96 Average Internal Skin Friction 7 Average Perimeter 7 Average Web Thickness 96
54. ctor rE l 1 Yi se Tao E b in which F applied force at node down the pile Copyright Oasys 1997 2014 Method of Analysis o The elements in P are obtained using the finite difference method Displacement Compatibility When elastic conditions at the pile soil interface are maintained the displacements of adjacent points along the interface are equal p7 p p eT F ER 0 The pile displacements are then calculated and shaft skin frictions are calculated from those pile displacements Effect of Rigid Boundary The elements of 2 apply only for the soil having an infinite depth i e a floating pile To allow for the effect of a rigid boundary on the pile displacement the mirror image approximation suggested by D Appolonia and Romulaldi was introduced The elements in I are then corrected to J i where l 7 vertical displacement factor for due to shear stress on element j l ij vertical displacement factor for due to shear stress on imaginary element j Pile Soil Slip Displacement compatibility requires that no slip occurs at the pile soil interface However real soils have a finite shear strength Slip or local yield will occur when the shaft skin friction reaches the limiting value so the elastic analysis as previously described is modified to take account of the possible slip For any loading stage first the displacements are solved on the ass
55. cy Pilset files is ignored Copyright Oasys 1997 2014 2 Pile Oasys Geo Suite for Windows 1 3 1 3 1 Components of the User Interface The principal components of Pile s user interface are the Gateway Table Views Graphical Output Tabular Output toolbars menus and input dialogs These are illustrated below O Pile 19 5 Workingl oad pls SEE Es Pd AMOS E IO 4 amp 5 X Er Eee pls f EX Se a coe ae es Units Material Bulk unit BM eu factor D Skin friction data Analysis Options tnn SLEE soil strength Skin friction pet Coeff of eath qs Limiting value Cepeciy Data El eee Delta ni aim pressure K Top Base Specified Value 1 O KN O kPa Ple Properties Defaults Drained tt I Ba S Material Properti Alluvium 18 00 Earth pressure 13 00 2 40 Ton pi KEERT RTD 20 00 Earth pressure 23 00 2 40 i 3 LMG Upper 20 00 Earth pressure 19 00 2 40 Drained Material ET 4 LMG Upnor 20 00 Earth pressure 22 00 2 40 Soil Profiles 5 LMG Upner Reduc 20 00 Earth pressure 22 00 1 70 Groundwater 6 THS 20 00 Earth pressure 22 00 1 70 a Proma Groundwater Map Ec 1 oo gt an AGeneralAFricion Beang jk tz Curve Data aN Enter TM name B WorkingLoad pls Tabular r Output Input Titles 1993 Notes 5 Tip Load Curve Data L amp P displacements applied ic Plasti 4 7mm
56. e Circular cross section e Shaft Diameter outside e Shaft Wall Thickness for hollow piles only e Wall Thickness at Base for hollow piles only Square cross section e External Side Width Copyright Oasys 1997 2014 Input Data e Shaft Wall Thickness for hollow piles only e Wall Thickness at Base for hollow piles only H Pile e Depth along Web e Width along Flanges e Average Web Thickness e Average Flange Thickness Units of cross section dimensions specifies the required units for entering cross section data in this dialog 5 6 4 Under ream The Under ream dialog presents the following input data Under ream Base diameter C Height H Im Height above top of under ream where skin Friction m is not calculated IL L NM e Base diameter Copyright Oasys 1997 2014 NON Pile Oasys Geo Suite for Windows e Height of the under ream e Height above top of under ream where skin friction is neglected 5 7 Material Properties The Material Properties section presents the following input data 5 7 1 Undrained Materials Each record in the Undrained Materials table view consists of the following items FIXED Undrained a ee a A a aterial factor 0m friction data mi pm for soi sent UT De cin D ule uus ue kN m kPa kPa kPa sx m Cr DR al all ER cR RR 1 Layer 20 00 60 00 260 00 Alpha Specified 0 45 Yes 200 00 2
57. e New on the program menu Set the preferred units for data input and output in the Units dialog The Units dialog is accessible by double clicking Units in the Gateway or via Data Units on the program menu Choose the analysis type via the Analysis Options dialog whether capacity or settlement or both Choose the effective stress profile whether calculated or user defined Input for user defined effective stresses profiles is explained in Item 8 Choose the datum type whether levels are entered as depths or elevations Choose the method for capacity analysis whether working load or design resistance and enter the factors for the selected method Copyright Oasys 1997 2014 About Pile 5 The Analysis Options dialog is accessible by double clicking Analysis Options in the Gateway or via Data Analysis Options on the program menu 4 opecify the type of analysis i e Working Load Design Resistance Code based and also the relevant parameters using the Capacity Data property sheet 9 opecify the method of settlement calculation i e Mindlin or t z curves and the relevant parameters such as Young s modulus of soil above and below pile base rigid boundary level number of load increments and number of pile elements Data input for settlement analysis is available via the Settlement Data dialog If the t z approach is selected then input the relevant t z curves and tip load curves to be used for the pi
58. e treated in a similar way to the shaft curves described above However there is no softening portion for the base Further the unloading behaviour is different as outlined below Copyright Oasys 1997 2014 Method of Analysis Force Displacement The pile base shows a response that is parallel to the initial elastic gradient on unloading with no tension capability Upon reloading the displacement accumulates with no load carried until it reaches the elastic unloading path retraces the unloading path in the opposite direction up to the updated yield stress on the initial loading path as tracked using assumptions described for shaft curves then follows the updated loading path to peak stress 2 2 3 Different Young s Modulus for Compression and tension Pile allows the input of different Young s modulus values for segments in compression and tension If the user selects this option in the Pile Properties page then the following action takes place in the solver e Initially all the segments are assumed to be in compression hence the Young s modulus value for compression is used for all the segments Analysis is performed e After the analysis if the sign of the stress of any segment is different from the initial sign the Young s modulus of that segment is modified accordingly and the analysis is performed again e his procedure is repeated until the signs of stresses obtained for the segments compression or tension ma
59. ected relative density 0 to 1 Original relative density 0 to 1 6 Get the value of 9 3l 7 Get the value of N using the Berezantzev method 8 If difference between the new value of No and value of No from step 3 is within tolerance stop the iteration else repeat steps 4 to 8 2 2 Settlement Settlement analysis calculates the settlement of a range of piles with different lengths and cross section dimensions and of the surrounding soil Pile soil slip is modelled together with the effects of soil heave inducing tension or settlement causing compression and negative skin friction Currently only solid square or circular piles can be analysed for settlements The solid square pile is modelled by an equivalent circular pile whose area is the same as the original square pile There are two methods provided by the program for the settlement analysis a Mindlin and b t z Curves 2 2 1 Mindlin Approach 2 2 1 1 Theory of Analysis Settlement calculation is based on theoretical analyses of the settlement of single compressible piles using linear elastic theory The analysis uses the integral method adopted by Mattes and Poulos and is explained briefly below Limiting shaft skin friction is calculated from the material properties Soil Displacements Copyright Oasys 1997 2014 NE Pile Oasys Geo Suite for Windows P Compression Tension P mu H El uM H AW pee y d A A d Stress on
60. ence Control Data Output Tabular Output Graphical Output Oasys Pile Titles Set Oasys Pile Titles BAR Pile1 Soil Profiles Sele Contribute to Level at layer top negative skin Layer friction CUT UO NE AA AS Defaults 1 1 000ArVod NO Fn 1 Soil Profile 1 Add Page lt Press lt TAB gt to start a new record Copyright Oasys 1997 2014 input Data 305 General Data Material type d Material name Undrained 1 Unit weight Level at top af the layer Material Factor For soil strength C at top of layer Cy at bottom of layer Layer contributes to negative skin Friction Mote 1 To select existing material select the desired material From the dropdown list 2 To use new material type the new material name in the combo box 3 Mew material name should not clash with existing material names This wizard contains pages to allow definition of layer properties and material properties The initial page allows definition of the layer data as well as general material data The type of material has to be specified in this page Depending on the type of material selected relevant pages to define other Drained or Undrained material properties will be shown 5 9 Groundwater Multiple groundwater profiles can be defined in the Groundwater Data table view Each tab corresponds to one groundwater profile Existing groundwater profiles can be edited or deleted and new grou
61. ent with no load carried until it reaches the elastic unloading path retrace the unloading path in the opposite direction up to the prevous maximum stress on the initial loading path then follow the initial loading path to peak stress 2 2 2 3 2 Chin Poulos For Chin Poulos t z curves the following equations are used to model the unload reloading behaviour e Unloading curve To o Z Zi gt Gmax Er f 2R e Reloading curve Copyright Oasys 1997 2014 Method of Analysis where z is the pile node displacement at load reversal H is a curve fitting constant for the unloading curve R is a curve fitting constant for the reloading curve H is a curve fitting constant for the shaft is the degradation factor for the reloading curve Ug is the difference between current shear stress and the stress at the load reversal point te is the limiting shear stress r is the radius of the pile Gmax is the initial shear modulus of the soil For the Chin Poulos tip load curves the following equations are used to model the unload reload behaviour e Unloading curve Py P Z Z ka Ry T 2R qu 4Gmax b E 2E marti i 1 8 e Reloading curve Po P zc j i PON a A R o F Ree 2R Almas TO 2E maxo i7 a8 4 82 1 8 1 87 Copyright Oasys 1997 2014 E HN Pile Oasys Geo Suite for Windows where p is the cu
62. er 0 60 m Ultimate Skin Friction Beta 0 80 Design Capacity C i i i i Ultimate Capacity C Ultimate Capacity T a o gt ao l Horz eff stress not lt alculated as K is unavailable f 800 0 400 0 100 0 50 00 Scale x 1 782 y 1 146 Capacity kN Force per unit length kN m Introduction to Graphics menu When the Graphical Output View is open the graphics menu shows the following options Copyright Oasys 1997 2014 Analysis egg Window Help gt EG o Font lll A To Al Save image k Results d Manual pls Graphical Output Graphical toolbar buttons EH Axis provides a reference grid behind the drawing de Set Scale this allows switch between the default best fit scale the closest available engineering scale e g 1 200 1 250 1 500 1 1000 1 1250 1 2500 or exact scaling The same options are available via the View menu s Set exact scale command Lj Save Metafile this save icon allows the image to be saved in the format of a Windows metafile This retains the vewed scale The metafile can be imported into other programs such as word processors spreadsheets and drawing packages XA Zoom Facility select an area to zoom in to by using the mouse to click on a point on the drawing and then dragging the box outwards to select the area to be viewed The program will automatically scale the new view The original area can be restored
63. ersion In this version limiting shaft skin friction is calculated from the material properties so reading of limiting shaft skin friction from a Pilset file is ignored Pile1 Titles Job Number Initials Last Edit Date Model Image 111111 B 22 Jul 2010 Job Title Subtitle pO Calc Heading written bv Pile version 19 1 0 1dev 3 1 Intranet Link and Emails To Mew the latest information regarding the Pile program or to contact the support team click on the internet LAR a support team buttons on the Start screen or select them from the standard toolbar The list below gives information that should be gathered and action that should be taken before contacting the support team version of Pile see top bar of program or Help About Pile specification of machine being used type of operating system pre check all input data Copyright O Oasys 1997 2014 Pile Oasys Geo Suite for Windows e access help file for information e check web site for current information e should a program malfunction be specified then attempt to repeat and record the process prior to informing the team The web site aims to remain up to date with all data regarding the program and available versions Should any malfunctions persist then the work around or fix will be posted on the web site The input file can be emailed to the support team by choosing the Help Email from the program menu 4 Assembling Data De
64. et up further stages from the Stage tree view This can be invoked from the Gateway or menu as shown l Model I i M Capacity Da Settlement E Material Pre Undrai Effective Stress Profiles Sol Profiles Nq Phi Curves ing oundwate t z Curve Data i Sail Profile Tip load Curve Data oP Effective St i l Na Phi Applied Loads or Displacements B Paste X Remove E tz Curve Dz i Elastic Written by Oasys Pile version 19 5 0 0dev Copyright Oasys 1997 2014 Staged Analysis 123 NI AEREAS AE Input Titles Ed Pile 19 5 Settlement calc Sq pls File Edit View Data Analysis Tools Graphics Window Help le C 3 Settlement calc Sq pls Stage Operations 3 Oasys Pile Titles Units Analysts Options capacity Data Y Applied loads amp displacements Settlement Data Y Thermal load Pile Properties Y Soil profiles Material Properties Water data Undrained Materials 2 Drained Materials 1 Soil Profiles 1 _ Groundwater 1 Delete stage Soil Profile Groundwater Map 1 Add stage New stage will be added after the current stage as shown on the Status bar Effective Stress Profiles 1 Ng Phi Curves 1 Nonlinear Curve 1 3 t z Curve Data Elastic Plastic User Specified Applied Loads amp Displacements 1 Thermal Load Displacement Radii Convergence Con
65. external skin friction accumulated within a soil layer outside the pile Within the layer AQL ang E where AL thickness of layer j p m MM average external perimeter of outside the pile in contact with soil in layer j j e average external skin friction in layer j outside the pile Similarly Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows A P Br a where MO a T Es incremental internal skin friction accumulated within a soil layer inside the pile E C i average internal perimeter of the pile in contact with soil in layer j j z average internal skin friction in layer j inside the pile 2 1 4 Shaft Friction Two basic methods are available total stress and effective stress The former is appropriate to clays and soft rocks and the latter to cohesionless soils and clays for long term loading where the stress conditions are likely to change 2 1 1 1 Total Stress Approach The friction per unit area f is given by f 200 where a an adhesion factor c the average undrained shear strength in the layer a may be either user specified or calculated by the specified API method API Method 1 The current API code recommends that for driven tubular steel piles a 0 5Y 95 w 21 0 Q 2 0 5 PO Ps 1 0 Y C 0 where one vertical effective stress Caution is required for cases where Y is greater than 3 or for long flexible piles a program warning is gene
66. f the program installation folder The examples have been created to show the data input for all aspects of the program and do not seek to provide any indication of engineering advice These examples can be used by new users to practise data entry and get used to the details of the program Brief Technical Description Pile Pile is a program which calculates the vertical load carrying capacities and vertical settlements of a range of individual piles in a layered soil deposit The theory is based on both conventional and new methods for drained frictional and undrained cohesive soils Currently the settlements are calculated for solid circular sections without under ream The main features of Pile are summarised below Either capacity analysis settlement analysis or both can be performed for a range of pile lengths and cross sections Settlements are calculated for only solid circular cross sections without under ream The soil is specified in layers Each layer is set to be drained frictional or undrained cohesive and appropriate strength parameters are specified Maximum values can be set for ultimate soil shaft friction stress and end bearing stress within each layer Levels may be specified as depth below ground level or elevation above ordnance datum OD Porewater pressures within the soil deposit can be set to hydrostatic or piezometric Pile capacities may be calculated for a range of pile lengths and a range of cross se
67. for entry of the job title Subtitle allows a single line of additional job or calculation information Calculation Heading allows a single line for the main calculation heading The titles are reproduced in the title block at the head of all printed information for the calculations The fields should therefore be used to provide as many details as possible to identify the individual calculation runs Notes allow the entry of a detailed description of the calculation This can be reproduced at the start of the data output by selection of notes using File Print Selection Copyright Oasys 1997 2014 Input Data The box in the right of the Titles window can be used to display a picture beside the file titles 5 1 1 Titles window Bitmaps To add a picture place an image on to the clipboard This must be in a RGB Red Green Blue Bitmap format Select the Paste Bitmap button to place the image in the box The image is purely for use as a prompt on the screen and can not be copied into the output data Care should be taken not to copy large bitmaps which can dramatically increase the size of the file To remove a bitmap select the button Remove Bitmap 5 2 Units The Units dialog is accessible via the Gateway or by choosing Data Units from the program s menu It allows the units for entering the data to be specified and reporting the results of the calculations These choices are stored in and therefore associated wi
68. from cumulative positive skin friction 2 1 3 6 Code Based If the code based option is chosen then one of the following design codes may be selected e EC7 No National Annex e EC7 United Kingdom e IS 2911 In EC7 No National Annex any of the three Design Approaches may be chosen as may the Model Pile Procedure or Alternative Procedure However in EC7 United Kingdom only DA1 and the Alternative Procedure are allowed Copyright Oasys 1997 2014 NES Pile Oasys Geo Suite for Windows 2 1 4 Solution Algorithm 2 1 4 1 1 divide the soil into required number of layers based on soil profile effective stress profiles groundwater profiles depth of the pile single or range changes in the pile properties eg under ream 2 calculate the vertical stress profile and vertical effective stress profile if not specified 3 compute the skin friction and end bearing if necessary of each layer as described below 4 compute the cumulative positive skin friction and negative skin friction taking into account layers which contribute to negative skin friction 5 compute the end bearing capacity of the pile 6 compute the working load or the design resistance of the pile 7 store the values obtained in steps 5 and 6 in order to plot the variation of the above quantities with depth Skin Friction Computation If total stress 1 5 6 Get the profile of c across the layer Get the profile
69. haviour e For API Clay the post peak behaviour is as shown in the figure below Copyright Oasys 1997 2014 Method of Analysis ot Force ur Displacement As can be seen from the figure above when the spring is loaded into the post peak softening zone the peak strength for the subsequent stage is reduced to the value of the current force in the spring In the subsequent stage also if the spring is loaded into post peak zone there is a further reduction in strength i e peak force This reduction continues until peak spring force falls to residual value Thereafter the behavour is similar to the non softening case described above Base curves Tip load curves The Slope of elastic portion is defined by Timoshenko amp Goodier 1970 as 1 u iol A H 4s G Where w is pile base displacement and P is pile baseload sb ry The following input parameters are required f pile radius G J shear modulus of soil input as a value at top of layer and gradient with depth Poisson s ratio The tip load curves are treated in a similar way to the shaft curves described above However they neither carry tension nor exhibit softening behavour Copyright Oasys 1997 2014 E HN Pile Oasys Geo Suite for Windows Force Displacement The pile base response should be parallel to the initial elastic gradient on unloading with no tension capability Upon reloading the displacement should accumulate displacem
70. he use of standard references The user is deemed to be conversant with standard engineering terms and codes of practice Itis the users responsibility to validate the program for the proposed design use and to select suitable input data Printed January 2014 Pile Oasys Geo Suite for Windows Table of Contents 1 About Pile 1 1 1 General Program Description 5 5 e pae eese n ERR oes Ea P esas s DARE aa AP SUO inaia Aa 1 lez ceret i o acer CENE ME 1 1 3 Components of the User Interface scion a e a a a i a e a aa aa Aa a aa 2 1 31 Working with the Gate WAY iiia iacscindc eiie eu ite aani aaa aae eaaa inn riera ia aaa 2 LIZ PFETEFENGES Innen Cet aA e ce eo E NAAA aa ce Gre toe EDAEN AED EE DEC Ode aAA AAAA 3 14 Step DY Step GUIdE eme m 4 2 Method of Analysis 7 21 GAD AC IO sexe rene 7 2 1 d Shafi F CUO EUER 8 2 51 Total Stress ADDEOSCDI a E EEEE EA 8 2 1 1 2 Hiecive Stress ADD acid dd E caus adicto aedusaysscsarnecian SIE 9 20 1 9 Ennung Shalt FEICBOR o diio ees leat iste o vL Es aie ieee nord Al og Dea vao dev V t Re Rp LR Rap 9 2 1 14 Negative Sm Ereloto naui o Pto ebbe bs E a kn v a 9 21 2 End Bean ari A AAA AA 10 2 1 2 1 TOlalotress Apoc eisin E E i dia 10 2 1 2 2 EMECUIvE Stress APOT da 10 223 e A OS 12 2 1 3 Bearing Capac hy asn caede o eat eere erede tec ba essc EEEE iesi 12 2 1 3 1 UMTS Capac ET ED em 13 2 1 3 2 Plugged Capac iV orere e Hos
71. iction and end bearing factor of safety on shaft skin friction only The limiting pile stress criterion can also be selected The program calculates the minimum capacity from all the selected combinations and prints it as the allowable capacity Also compression and tension related parameters need to be specified separately At least one of tension or compression capacity computations should be selected For more information refer to Allowable Capacity Working Load Approach Copyright Oasys 1997 2014 input Data 85 5 4 2 Design Resistance Design Resistance Compression Calculate compressive capacity Partial Factors Use partial Factors Shaft resistance Factor Base resistance Factor Global Factor Use global Factors Total resistance Factor Model Factor Tension Calculate tensile capacity Shaft resistance Factor Model Factor In this approach either compression or tension computations or both can be selected For the compression case the program computes the lowest capacity from the selected combinations partial factors combination and or global factor combination and reports it as the design capacity Design resistance does not include any contribution from negative skin friction For more information refer to Design Resistance Limit State Approach Copyright O Oasys 1997 2014 NN Pile Oasys Geo Suite for Windows 5 4 3 EC7 No National Annex Eurocode Design Approach D
72. if thermal load is specified and is active Pile cross section The different types of cross sections available are Solid Circular Hollow Circular Solid Square Hollow Square and H Pile Settlements are calculated for solid circular and solid square sections without under ream only If other cross section types are selected an error message will appear upon analysis Young s modulus This is used in the settlement calculation Different Young s modulus values may be set for segments in compression and tension If the Use different values option is unchecked the user may enter only one Young s modulus value for all segments Copyright Oasys 1997 2014 NON Pile Oasys Geo Suite for Windows Linear coefficient for thermal expansion coefficient describing the relative change in length of pile per unit of temperature change This is relevant only when thermal loading is applied to the Pile Under reams Solid only This option is available only if Solid pile type option is selected Reduction Factor for Internal Skin Friction This factor is used in calculating the internal skin friction Pile head fixed or free By default it is free Copyright Oasys 1997 2014 input Data o5 5 6 2 Pile Lengths The Pile Lengths dialog presents the following input data Pile Lengths Single pile length Minimum pile length Maximum pile length Number of increments Increment size Depth of pile
73. ight is used a is a function of D B and 4 dy pertains to the soil of overburden o is the effective vertical stress at the level of pile toe The value of N is then calculated from the resulting bearing capacity 2 1 2 3 Limiting End Bearing Irrespective of the approach followed the end bearing stress q may be limited to a user specified value If this value is set to zero then the end bearing stress is assumed to increase indefinitely with increasing toe depth 2 1 3 Bearing Capacity The following capacities are calculated by the program Solid piles e Ultimate Capacity e Allowable Capacity e Design Capacity Hollow piles e Plugged Capacity e Unplugged Capacity fixed and changing internal soil level e Ultimate capacity e Allowable capacity e Design Capacity Solid piles The total bearing capacity of solid piles is Q Q Q where Q cumulative skin or shaft friction Q end bearing For piles in tension Q 0 Hollow piles The total bearing capacity of hollow piles is the lesser of Copyright Oasys 1997 2014 Method of Analysis 13 lugged Qu T bw v Qe and Q Qry Q4 Qe unplugged where Q cumulative internal skin friction KN Q cumulative external skin friction kN Qi end bearing acting over the soil plug area kN Q w end bearing acting over the pile wall area kN For piles in tension Q Q Q 0 2 1 3 1 Ultimate Capacity Solid Piles
74. ilarly needs to account for the accumulated irreversible displacements of previous cycles and follows a similar shape of curve to the remaining portion beyond the maximum displacement reached on the previous cycle by Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows referring to the values of monotonic peak and residual force while accounting for the accumulating irreversible displacements from all of the previous cycles fi fo 1A 1 e7 llaw Epi Awptm veras Cycle 0 Force Cycle 1 g Residual stress point Displacement As noted prevously the form of the equations for the current value of peak force and the degradation to post peak minimum force mean that for one way cycling it may be possible for the peak force value to lie above the monotonic curve as accumulating irreversible strains of the prevous cycles only and not the current cycle are accounted for therefore a comparison of the top portion of the loading curve to the monotonic curve is made to ensure that accumulating displacement under one way loading does not cause the current force point to go above the monotonic curve Under two way loading this is less of an issue as irreversible displacements in both directions tend to degrade the peak force under low values of average absolute displacement and the monotonic curve is less critical to the behavour Base curves tip load curves The tip load curves ar
75. ion at the bottom of layer C Bottom is ignored in this case The following fields relate to Friction data Method method of calculating Alpha the adhesion factor This is one of API method 1 API method 2 or user specified value of Alpha adhesion factor if user specified Limiting value Specified select Yes to specify the limiting value Value friction value is limited to this value When the limiting value of the frictional shear stress is entered as zero the maximum allowable frictional shear stress between the pile and the material is assumed to be infinite t z curve the stress displacement curve to be used for calculations if the settlement calculation method selected is t z curves This column is active only when the analysis type in Analysis Options is Settlement and the calculation method in Settlement Data is t z curves The following fields are related to End bearing Method method of calculating N the bearing capacity factor This is one of user specified or calculated Ne user specified bearing capacity factor Limiting value Specified select Yes to specify the limiting value Value bearing value is limited to this value When the limiting value of the end bearing stress is entered as zero the maximum allowable end bearing stress for the given material is assumed to be infinite Tip load curve the stress displacement curve to be used for calculations if the settlement calculati
76. iving hollow piles or H piles it may not be possible to mobilise the full theoretical internal friction this may be too great to allow the plug end bearing force to push the soil up inside the pile typically in clay soils In this situation the pile becomes plugged and the level of soil inside is lower than that outside If the end bearing later increases within a deeper layer the accumulated internal friction will be fully mobilised again and more material will be pushed up inside the pile However the internal capacity will be less than if the plug level is at the ground surface Thus there are two cases for calculation of unplugged capacity as described below e Case 1 Internal soil level is the same as external soil level wherein the internal skin friction is calculated assuming an internal soil profile similar to the external soil profile Thus the external and internal friction will be in the ratio of external perimeter to internal perimeter of the pile e Case 2 Internal soil level changes with the driven pile depth In this case calculations are made at each depth increment to ensure that soil is pushed inside the pile only if the entire skin friction has been mobilised as follows Consider two pile embedment depths d1 and d2 such that d1 d2 Copyright Oasys 1997 2014 Method of Analysis Incremental Layer Depth Assume that the incremental layer does not contribute to negative skin friction If Quart
77. lates between the levels to determine the values of prescribed soil displacement at each node down the pile It assumes zero displacement at top and bottom of pile if not entered Interpolation of prescribed displacement down the pile shown below Copyright Oasys 1997 2014 118 Pile Oasys Geo Suite tor Windows 3 3 3 oo o Pile Oasys 118 Pile Oasys Geo Suite tor Windows 3 3 3 oo o Suite for Windows Single data is entered Multiple data is for prescribed entered for prescribed displacement displacement This table view changes when Code based capacity calculations are selected as shown below EC7 No National Annex CodeTests amm uM a Loads amp a EN Description E ue E Applied load Favourable ET Permanent oe kN Saas Leo He 00 0 00 es Yes a Top Load 0 00 500 00 es Mo ERR 4 Press lt TAB gt to start a new record For this case whether a load is permanent and whether a load is favourable need to be specified Copyright Oasys 1997 2014 Input Data 9 EC7 United Kingdom Code Tests pls Applied Loads amp Displacements a 42 B C D E e Depth below Description ground level Applied load A Al e E EN IS Detaults 0 00 0 00 Top Load 0 00 2500 00 1 00 1 00 Z Press lt TAB gt to start a new record In this case the explicit load factors for A1 and A2 load factor sets need to be specified 5 16 Displacement Radii Each rec
78. le displacement that has occurred according to the following equation which applies provided the previous cycles have been in the pre peak region of the t z curve maxi 2 fyi Wai Wy i 2 AWpLi 1 Aw Li 2 f max iz f y i 2 JJ When using this equation if the yield force fi has decreased from its previous value on this side of the axis f p due to degradation of peak force from accumulated irreversible displacement then f Is replaced with e o and the equation becomes Hien H pi pi 2 AWgii ic Wpo Copyright Oasys 1997 2014 e Pile Oasys Geo Suite for Windows fat 0 5 1 At fy 2 5 Cycle 1 AS Cycle 2 B Unloading point E Reloading point e Yield point g CN DW 1 Displace ment The above graphs show symmetrical two way cycling however the above equations are also designed to model the behaviour of unsymmetrical cycling such as one way cycling as shown below When there is post peak degradation of the monotonic loading curve a check is made to ensure the force displacement path is limited by the monotonic post peak exponential curve This is more of an issue for one way rather than two way loading as additional irreversible displacement during two way loading ensures that the peak force degrades more with absolute displacement than monotonic loading alone This is described further in the post peak section below Force m Unloading poi
79. le shaft and the pile base respectively A particular type of t z or tip load curve can be input by double clicking the appropriate type under the t z Curve Data or Tip Load Curve Data gateway item or under the Data t z Curve Data or Tip Load Curve Data item on the program menu 6 Specify the type length and diameter of pile via the Pile Geometry dialog Follow the wizard to enter pile properties pile lengths and pile cross sections The Pile Geometry dialog is accessible by double clicking Pile Geometry in the Gateway or via Data Pile Geometry on the program menu opecify the input data for soil material whether undrained or drained 7 1 Specify any undrained material data in the Undrained Material table view The Undrained Material table view is accessible by double clicking Material Properties Undrained Material in the Gateway or via Data Material Properties Undrained Material on the program menu 7 2 Specify any drained material data in the Drained Material table view The Drained Material table view is accessible by double clicking Material Properties Drained Material in the Gateway or via Data Material Properties Drained Material on the program menu 8 Specify soil layers in the Soil Profiles table view Multiple soil profiles can be defined The Soil Profiles table view is accessible by double clicking Soil Profiles in the Gateway or via Soil Profiles on the program menu 9 Specify any hydrost
80. n of minimum post peak force post peak displacement to minimum post peak force shape parameter controlling the rate of degradation 5 13 3 Chin and Poulos Each record in the Chin and Poulos t z Curves table view consists of the following items E temp2000 pls Chin Poulos t z Curves o ms pem mE ge guum In A E E Young s modulus E Poisson s ratio Hyperbolic curve Unloading curve Reloading curve Degradation Description Top Gradient fitting constant Rfs fitting constant Ry fitting constant R constant 6 s A 9 AAA Defaults Chin Poulos t z 0 000 OO hin Poulos t z 1 Cell A 2 Description the name of the curve Young s modulus E Top the Young s modulus at top of the soil layer Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio of the material Hyperbolic curve fitting constant R the hyperbolic constant for pile shaft elements Unloading curve fitting constant R the curve fitting constant for the unloading curve Reloading curve fitting constant R the curve fitting constant for the reloading curve Degradation constant the secant modulus degradation value due to cyclic loading Copyright Oasys 1997 2014 Input Data 111 5 13 4 API Each record in the Empirical t z Curves table consists of the following items EE Pilel API t z Curves Lo O SO O 1 D D m
81. n there is no material change at a particular node the t z curve of the node from the last increment of the last stage is used However it the node is in a drained material and effective stress changes between stages the program generates the new t z curve for this revised stress state and uses Copyright Oasys 1997 2014 EM Pile Oasys Geo Suite for Windows the same for the new stage The same procedure is followed if the material changes at a node between stages 7 Output 7 1 Analysis and Data Checking The data can be analysed via Analysis Analyse from the program menu or the analysis button 2 on the analysis toolbar Tools Graphics Window Help ltl ez x File Edit View Data ESSE UPd s Delete Results E Input mn don I 3 Prior to analysing the data the program performs various checks and gives warnings errors if the data is not consistent Warnings do not prevent an analysis Errors do and must be corrected before an analysis may proceed Y Manual pls Analysis checks Checks prior to analysis Errors 1 User defined effective stress profile i selected but the values are not entered in effective stress profile table Effective Stress Profile Warnings 1 The bottom most layer is assigned Total stress material For this layer the cohesion Is assumed to be constant at Lu Top Le cohesion specified at the top of this layer The user specified value of cohesion at the bottom of this
82. nal As per IS 2911 the N values for a drained soil type are computed based on the type of pile selected and minimum global factors of safety imposed Partial factors may be chosen in Copyright Oasys 1997 2014 NES Pile Oasys Geo Suite for Windows addition to global factors of safety but this is not mandatory When the partial factors are also selected the program computes the allowable load as the minimum from both the global factor approach and the partial factor approach A tension reduction factor for skin friction computation should be specified The critical depth can be entered either as an absolute value or in terms of the number of pile diameters Material factors may be optionally enabled The program then uses the factored material parameters in pile capacity calculations The material factors should be specified on a per material basis for tang or cohesion depending on the type of soil material These values then would need to be entered in the drained undrained materials table views The contribution of the Ny term in the evaluation of end bearing capacity may be selected or ignored The excess weight of pile over the surrounding soil may also be optionally taken into account This may be relevant for offshore piles or other piles which protrude above the ground To model piles protruding out of the ground dummy soil layers with nearly zero unit weights above the actual ground level should be defined When exercisi
83. nd Cyclic Loading The Thermal and Cyclic Loading dialog presents the following input data 7 p Thermal and Cyclic Loading y 2 o B 05 7 Non cydic Temperature change over ambient Cydic Number of cydes Thermal Amplitude of temp Mechanical Level Amplitude of load cyde Non cyclic if checked non cyclic thermal load will be applied Temperature change over ambient the change in pile temperature from the ambient temperature Cyclic if checked cyclic thermal load or cyclic mechanical load will be applied depending on the selection Number of cycles the number of loading cycles to be applied Thermal if selected thermal loading cycles will be applied Amplitude of temperature change the change in temperature from the mean temperature Mechanical if selected mechanical loading cycles will be applied Level level at which the mechanical load is to be applied Amplitude of load cycle the load to be applied Copyright Oasys 1997 2014 122 Pile Oasys Geo Suite for Windows 6 Staged Analysis Oasys Pile program allows the users to analyse different stages which follow one another This is available only when t z curves option is selected The following data can be changed between different stages Applied loads and displacements Thermal loads Soil profile Groundwater data When a new file is created the program inserts the default Initial stage Stage 0 The user can s
84. ndwater profiles can be added using the context menu obtained by right clicking on any tab This can be hydrostatic or piezometric Each record in the Groundwater table view consists of the following items Copyright Oasys 1997 2014 106 Pile Oasys Geo Suite for Windows Codelests pls Groundwater Depth below Pressure Unit weight of water Groundwater ground level m kPa KN m Defaults 3 5 1 JU o 0 1 Groundwater profile 14 2 Groundwater Pro amp Enter depth of phreatic surface or piezometer Level Depth below ground level level depth at which the pressure is the specified Pressure pressure at the level depth when a piezometric profile is entered Unit weight of water the value of unit weight of water The entry in the first record alone is available for input This first line of the table view allows a single value for the unit weight of water to be added On subsequent lines levels depths and pressures can be entered to create a piezometric profile Interpolation between the points is linear and the water profile beneath the lowest point is assumed to be hydrostatic If only one data point is entered the program will also assume a hydrostatic groundwater distribution For hydrostatic distributions the water pressure u is calculated from U Z lw where z depth below water table level Y Specified unit weight of water Thus a partial hydrostatic condition can be modelled by
85. need to be specified The negative skin friction is considered only in compression calculations as unfavourable permanent load It is not considered at all in tension calculations It is recommended to refer to A 3 1 section in the UK national annex for guidance on these factors These values can be ignored if there is no negative skin friction in the model The calculations for both DA1 and DA2 combinations can be requested in the tabular output of results by selecting the relevant check box Copyright Oasys 1997 2014 input Data 39 5 4 5 IS 2911 Is 2911 Pile Type Concrete de Driven cast in situ Bored cast in situ a Driven pre cast Bored pre cast n Global Factor of safety in compression Factors of Safety Global Factor of safety in tension Partial Fos Use partial FoS in addition to Global Fos Partial Factor an shaft compression Partial Factor on base compression Tension reduction factor For skin Friction Critical Depth Number of diameters C2 Absolute value Number of pile diameters 15 8 Material Factors Enable material Factors Consider N Gamma in end bearing capacity computation Limit effective overburden pressure in skin Friction compukation to the value at critical depth Account For excess weight of pile over equivalent soil column Density of pile For IS 2911 the type of pile factors of safety and critical depth may be specified The other parameters are optio
86. ng this option the density of pile material should be entered Copyright Oasys 1997 2014 Input Data oot 5 5 Settlement Data Settlement Data Calculation method E Mindlin t z curves Young s modulus of soil above toe level of pile 20000 Young s modulus of soil below toe level of pile 40000 Rigid boundary level 200 Poisson s ratio of soil Number of pile elements Number of increments Increment type Loads only 2 Displacements only Print increment results at rate of 1 for every Indude effect of soil above pile base in base displacement calculation Note Settlements are calculated for solid circular without under ream sections only cancel Settlement data is enabled when settlement analysis is selected Calculation method the calculation method to be used should be selected The methods provided are Mindlin and t z curves Young s Modulus of soil above toe level of pile and Young s Modulus of soil below toe level of pile are average values representing the soil stiffness above and below the pile toe respectively Poisson s ratio is the average value from the different soil layers around the pile Include effect of soil above pile base in base displacement calculation whether the stiffness at the base node is to include the effect of soil above the base Depth of rigid boundary the level at which the soil displacements are zero Number of pile elements the pile is divided into the num
87. nitial loading f and decreases at half the rate of the unloading force point to a minimum value of A Where bs is the peak force of the reloading cycle which will have degraded as a function of the amount of pre and post peak irreversible displacement accumulated The yield point for the subsequent reloading stage can therefore be defined in the same manner as before where f is used in place of f when post peak displacement has occurred Lh Jri 1 TUSILT fria E fri 1 fji hh In order to maintain a similar displacement to mobilise peak force during reloading and Subsequent unloading stages the displacement to peak force is proscribed as a function of the amount by which the yield force has reduced from the maximum force as well as by following the amount of irreversible displacement that has occurred according to the following equation which applies to the post peak region of the force displacement curve where w is the displacement at stress reversal points W is the difference between the equivalent elastic displacement at the current failure force not peak force and the displacement at the current failure force Es o fy W pi Wpi 2 t AWoti 1 AW i 2 j dnd n fyi When using this equation if the yield force f has decreased from its previous value on this side of the axis f y i2 due to degradation of peak stress from accumulated irreversible displacement Copyright
88. nt SW Reloading point Yield point Displacement As can be seen from the graph above cycle 2 is limited by the initial monotonic curve i e blue Copyright Oasys 1997 2014 Method of Analysis curve for cycle O Post peak behaviour If the spring is loaded to a failure force f after passing through peak force P then the first unloading curve is a scaled down version of the initial loading curve factored by t t as follows The unloading stage initially follows a path parallel to the linear elastic portion of the loading curve The unloading yield force lies on the negative side of the spring force axis and is a proportion of the failure force f and is therefore less than b The displacement at unloading yield Wy 1 can be found from following the elastic gradient back from the displacement at maximum force w ad The first unloading peak force lies on the negative side of the force axis and is the same as the failure force of the initial loading stage f The displacement of the peak stress point on unloading Wo 0 is calculated based on the assumption that the displacement from zero force to peak force is always equal to the input value w which describes the monotonic displacement required to mobilise peak shaft resistance As before on subsequent reloading and unloading stages a detailed track of the yield and peak force points must be carried out The peak force that can be reached on subsequent
89. o Suite for Windows value of the corrected relative density 0 to 1 Limiting value Specified select Yes to specify limiting value Value the bearing value is limited to this value When the limiting value of the end bearing stress is entered as zero the maximum allowable end bearing stress for the given material is assumed to be infinite N Curve used for calculating the value of No from friction angle Tip load curve the stress displacement curve to be used for calculations if the settlement calculation method selected is t z curves This column is active only when the analysis type in the Analysis Options is Settlement and the calculation method in the Settlement Data is t z curves This option becomes available for Berezantzev and Bolton methods Berezantzev Ak Bk Curves or user defined N curves may be selected For information about the methods used to evaluate pile capacities using the effective stress approach refer to the topics Shaft friction Effective stress approach and End bearing Effective stress approach When using code EC7 additional fields pertaining to material factor sets are available E CodeTests EC7 Generic pls Drained Materials EAN TA N resp Sores pr AAA a Z AA aB End bearing data value qs material factors End bearing me EEE qb Limiting value Value Mi M2 computation Na Ph PhiD Phicv Ir Top Base Specified Value a Phi curve MI M2
90. of a across the layer user specified value or from API methods 1 or 2 Get the profile of f__ and f if necessary across the layer taking into account the limiting skin friction in the layer Get the average value of f and f for the layer Get the perimeter of the pile in the layer both external and internal Compute external and internal skin friction provided by the layer Else if effective stress 1 Get the profile of f based on the method selected If B method a Get the user specified value p b Get the profile of f from o profile using f B o Else if earth pressure method Copyright Oasys 1997 2014 Method of Analysis 21 a Get the profile of o user specified or using the value of earth pressure coefficient K viz o Ko b Get the profile of f using the relation f o tan where dis the friction angle between the pile and soil 2 Get the average value of f and f for the layer 3 Get the perimeter P of the pile layer both external and internal 4 Compute external and internal skin friction provided by the layer 2 1 4 2 End Bearing Computation 1 Get the profile of bearing pressure q If total stress a Get the profile of undrained cohesion C across the layer b Get value of N user specified or calculated based on embedment depth c Get the profile of bearing pressure from q N c Else if effective stress a Get the
91. on method selected is t z curves This column is active only when the analysis type in Analysis Options is Settlement and the calculation method in Settlement Data is t z curves For information about the methods used to evaluate pile capacities using the total stress approach please refer to the topics Shaft friction Total stress approach and End bearing Total stress approach When using code EC7 additional fields pertaining to material factor sets are available Copyright Oasys 1997 2014 100 Pile Oasys Geo Suite for Windows ES CodeTests Undrained pls Undrained Materials G Hjtj Skin friction data AnnaL 95 Limiting value pig Top Base Specified Value M1 _ kPa kPa Defaults No 0 50 No No Yes K P End bearing data End bearing Ne me TO Limiting value qb material factors computation Base Specified Value M1 M2 Nc Specified 1 00 Nc Specified 36 00 Calculated ejes w Tu 200 00 qb Specified 50 00 100 00 lan General Friction A Bearing The M1 set values are always 1 00 M2 set values are different from 1 00 and are specified in the code for only some parameters C Phi etc However skin friction and end bearing computations can be specified that do not explicitly depend on these parameters For example q Or q can be specified directly or N can be used to calculate them In these situations the corresponding M2 parameters would need to be
92. on the program menu Pile performs a check on data for consistency Correct any errors that are shown in the subsequent report of warnings and errors Inspect the results in the Tabular Output view and or the Graphical Output These are accessible by double clicking the Output Tabular Output Output Copyright Oasys 1997 2014 About Pile Graphical Output in the Gateway via View Tabular Output View Graphical Output on the program menu or via the appropriate buttons on the Pile toolbar 20 Adjust the data and re analyse as necessary 2 Method of Analysis 2 1 Capacity The soil is split up into a number of layers each having necessary data to calculate end bearing and skin friction The program will calculate bearing capacity at discrete elevations either to provide a single bearing capacity at a single elevation or to develop a bearing capacity versus depth profile over a specified range of elevations The calculation procedure will involve identifying a number of sub layers within each specified soil layer corresponding to depths at which capacity is to be assessed where these fall within a layer depths at which capacity is to be assessed to allow a graph to be produced changes in pile properties i e under reams changes in groundwater pore pressure profile If there are n layers between the ground surface and the toe of the pile a E a E IE gel where AQ T Qs incremental
93. oosing Tools Preferences from the program s menu It allows the modification of settings such as numeric format for output show welcome screen print parameters and company information These choices are stored in the computer s registry and are therefore associated with the program rather than the data file All data files will adopt the same choices Preferences Numeric Format he r Company Info Engineering significant figures Decimal le decimal places Page Setup Scientific significant Figures Smallest value distinguished From zero 1e 006 e Save file every minutes Show welcome screen Numeric Format controls the output of numerical data in the Tabular Output The Tabular Output presents input data and results in a variety of numeric formats the format being selected to suit the data Engineering Decimal and Scientific formats are supported The numbers of significant figures or decimal places and the smallest value distinguished from zero may be set Restore Defaults resets the Numeric Format specifications to program defaults A time interval may be set to save data files automatically Automatic saving can be disabled by clearing the Save file every check box Show welcome screen enables or disables the display of the Welcome Screen The Welcome Screen will appear on program start up and gives the option to create a new file to open an existing file by browsing or to open a recently used file
94. ord in the Displacement Radii table view consists of the following items Manual pls Displace fo Ej Defaults 1 o o 050 z 1 00 1 20 1 40 1 50 1 60 1 80 8 3 i0 T 1 z 3 1 d4 i5 J6 iz f Enter Radus From pile center at which soil displ Copyright Oasys 1997 2014 EM Pile Oasys Geo Suite for Windows Radius the radius from the pile at which soil displacements are to be calculated If the displacement radius entered is less then the shaft base radius the displacements are calculated at the interface of pile and soil i e at the radius of shaft base 5 17 Convergence Control Data The Convergence Control Data dialog presents the following input data Convergence Control Data Maximum number of iterations 1000 Tolerance For displacement 0 01 Tolerance For skin Friction Damping coefficient Cancel Tolerance for displacement the maximum change of displacement between successive iterations The absolute error will be considerably larger typically by a factor of 100 Tolerance for skin friction the maximum error in the shaft skin friction i e how much the skin friction exceeds the limiting value This is an absolute value Damping coefficient can be enhanced if convergence is slow If instability is apparent it may possibly be solved by reducing this coefficient Copyright Oasys 1997 2014 Input Data 121 5 18 Thermal a
95. ove which has been derived based on the theory in the Berezantzev 1961 paper the effect of both Y and is considered 6 Finally calculate the value of end bearing pressure q dp AYB Byaz0 where O effective vertical stress at the level of pile base y unit weight of soil at the level of pile base If the water table is above or at the location of the pile base buoyant unit weight is used Otherwise bulk unit weight is used B diameter of the pile li User defined Nq Phi curve This calculation algorithm is performed when any user defined Nq Phi curve is selected in the Nq Phi curve field of the Effective stress table view 1 Get the user specified value of drained friction angle 4 2 Get the value of Nq based on user specified equation or user specified look up table 2 1 4 2 2 Bolton Method This is a more refined approach is given by Bolton 1984 taking into account dilatancy effects and the influence of stress level particularly with heavily loaded piles It involves the following steps 1 Get the user specified values of band lp where corrected relative density 0 to 1 2 Get the value of Y gt 3lp 3 Get the value of No using the Berezantzev method Copyright O Oasys 1997 2014 Method of Analysis 25 4 Get the value of mean effective stress p using the relation p YN o 5 Get the value of l using the relation I 10 In p 1 where Corr
96. pile Stress on soil Stresses acting on Pile and Adjacent Soil The soil displacements adjacent to the pile can be expressed by m A 0 3 z lp where p 2 soil displacement vector ip p d shaft skin friction vector Copyright Oasys 1997 2014 Method of Analysis ip S i E soil Young s modulus n number of nodes on pile shaft 1 soil displacement factor matrix d 43 lja ma ma lin la d la t Be ua d ij alie dy La l2 ban ban inb dy lai ls rar rar loa bb in which d diameter of pile shaft dy diameter of pile base where superscript s and subscript b denote soil and pile base respectively The elements in gi are derived from integrations of Mindlin s equations The equation can be rewritten in the form of soil stiffness UM otn o T 07 Pile Displacements The pile shaft stresses at nodes can be expressed by 487 p EPR IP o Y where superscript p denotes pile p Pj pile displacement vector Copyright Oasys 1997 2014 E Pile Oasys Geo Suite for Windows Pi P P3 pFj 5 Pr Ps length of pile element EP pile Young s Modulus A Ka z A 1nd A pile cross sectional area P pile action matrix 1 1 0o 0 g 1 2 1 O0 g P un g o 0 g 1 z 1 0 0 0 0 02 2 h 3 2 0 0 0 0 0 133f 12f 1067f in which f TR Y applied stress ve
97. placement Radii E Pe astic a 0 Layer 2 Chin amp R Convergence Control Data E 2 000 Cu amp op 60 00 kPa Cu tase 200 00 kPa SE AT 1 1 E A Stage tree view 5 4 00 ara rds pc EE ian i Empirica m o e LO A CENTRE E PO User Specified bos cT c NEM E Tip Load Curve Data 3 000 Elastic Plastic 1000 qu EIE CH uS RE x Empirical AP 1993 Mer ETT Empirical Vijayvergiya 1977 YU jM l Applied Loads amp Displacements 1 y Aii s Thermal Load MAS DEGAS ls i Calculation profile Single a Displacement Radii Dila lanrth 2n nnnn m For options other than Units and Preferences and Analysis Options a check mark is placed against the option once data has been entered Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows 5 1 Titles The first window to appear for entry of data into Pile is the Titles window Pile1 Titles Jab Number Initials Last Edit Date Model Image 111111 Ld 22 Jul 2010 Job Title Subtitle pO Calc Heading written bv Pile version 19 1 0 1dew This window allows entry of identification data for each program file The following fields are available Job Number allows entry of an identifying job number By clicking the drop down button the job numbers previously used can be accesed Initials for entry of the user s initials Date this field is set by the program at the date the file is saved Job Title allows a single line
98. ponse of piles MSc thesis Imperial College London Berezantzev V G Khristoforov V S and Golubkov V N 1961 Load bearing capacity and deformation of piled foundations Proceedings of the 5th International Conference on Soil Mechanics and Foundation Engineering pp 11 15 Bolton M D 1986 The Strength and Dilatancy of Sands Geotechnique 36 No 1 65 78 BS EN 1997 1 2004 Eurocode 7 Geotechnical design Part 1 General rules Chin J T and Poulos H G 1991 A T Z Approach for Cyclic Axial Loading Analysis of Single Piles Computers and Geotechnics 12 1991 pp 289 320 D Appolonia E and Romualdi J P 1963 Load Transfer in End Bearing Steel HPiles Journal of the Geotechnical Engineering Division ASCE Vol 89 IS 2911 Part1 Section 1 Section 4 2010 Design and Construction of Pile Foundations Code of Practice Ken Fleming Austin Weltman Mark Randolph Keith Elson 2009 Piling Engineering Third edition Mattes N S and Poulos H G 1969 Settlement of Single Compressible Pile Journal of the Soil Mechanics and Foundation Division Proceedings of ASCE Volume 95 No SM1 January 1969 pp 189 206 NA to BS EN 1997 1 2004 UK National Annex to Eurocode 7 Geotechnical design Part 1 General rules Poulos H G and Mattes N S 1968 The Settlement Behaviour of Single Axially Loaded Incompressible Piles and Piers Geotechnique Volume 18 pp 351 371 Poulos H G and Mattes N S 1969 The Behaviour of Axially Lo
99. proposed by Berezantzev as a function of drained friction angle y The relationship can be defined explicitly or as a look up table 111 N based on mean effective stress relative density and friction angle A more refined approach is given by Bolton 1984 taking into account dilatancy effects and the influence of stress level particularly with heavily loaded piles This is an iterative approach based on the following expressions I lj 10 In p 1 where corrected relative density 0 to 1 original relative density 0 to 1 p mean effective stress kPa calculated as p o 20 3 6 3l degrees where critical state angle of friction degrees p VN a N is estimated using the Berezantzev method To start the process it is suggested that No is first estimated using d iv N calculated based on friction angle depth ratio depth width and friction angle corresponding to the soil of overburden This approach is based on the paper by Berezantzev et al 1961 wherein the bearing capacity is calculated from qp A YB B as where A B are coefficients depending upon q and are read from the A and B graphs Copyright Oasys 1997 2014 12 Pile Oasys Geo Suite for Windows respectively y is the unit weight of soil at the level of pile base If the water table is above or at location of pile base buoyant unit weight is used Otherwise bulk unit we
100. rated API Method 2 Earlier editions of the API code advised that Copyright Oasys 1997 2014 Method of Analysis 9 a 1 0 C lt 24kPa a 0 5 c gt 2kPa with linear interpolation between these values 2 1 1 2 Effective Stress Approach The friction per unit area f is computed by the following two methods Beta Method The Beta method relates friction directly to vertical effective stress o fs Bo Earth Pressure Method More conventionally f o tan where o average horizontal effective stress in layer lo soil pile friction angle o either user specified or calculated using a Ko where K earth pressure factor 2 1 1 3 Limiting Shaft Friction Irrespective of the approach followed the skin friction per unit area f may be limited to a user specified value If this value is set to zero then the friction is assumed to increase indefinitely as one goes down the length of the pile 2 1 1 4 Negative Skin Friction Some layers may be defined as providing down drag in which case the cumulative capacity cannot contribute to the bearing capacity The negative skin friction Q must be calculated separately to ensure that the factors of safety or partial load factors are applied correctly In bearing capacity calculations negative skin friction is always calculated separately Copyright Oasys 1997 2014 IT Pile Oasys Geo Suite for Windows Cum
101. reloading and unloading stages is again a function of the amount of irreversible displacement that has accumulated from previous cycles with a limit placed on the peak force that it must not exceed the minimum post peak failure force f reached on previous cycles Degradation of peak force in one direction also limits the peak force in the opposite direction to the same value This is taken into account using the relationship for peak force based on accumulated irreversible displacement as before fpi fria Fpi1 When irreversible displacement accumulates from two way cycling ie fo 11 1 2 f eg 1 ES e 2 4 LAw py i 1 Awpum Awres The post peak irreversible displacement that is accumulated on each cycle Aw is the difference between the equivalent elastic displacement at peak force Aw rather than the equivalent elastic displacement at current force compared to the current post peak displacement w This ensures that the peak force of the subsequent cycle calculated using the equation above equals the failure force of the previous cycle Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows A Welo Aw Wel PW o Force Cycle 0 B Initial point Displacement The yield force for the reloading stage again reduces with the unloading path as described earlier During unloading the yield force for the reloading cycle is initially at the maximum force obtained on i
102. rogram Description 1 Material 103 105 Geometry 76 Material Description 98 100 Graphical Output 2 128 Material Layer 107 Graphics Toolbar 2 Material Layers 20 Ground Level 1 Material Properties 98 Groundwater 105 Mean Effective Stress 10 Groundwater Data 76 Mud line 1 Groundwater Pressure 105 N H Nc 10 Height of the Under ream 97 Negative Skin Friction 9 14 Hollow 93 Non Linear Curves 100 108 Hollow Piles 12 notes 78 Hollow Sections 10 Nq 21 100 108 Horizontal 107 H Pile 93 96 O H piles 10 H section 1 Ordnance Datum 1 Hydrostatic 1 105 Dp Partial 105 Image 79 PDF 132 Incremental External Skin Friction 7 Peizometric 1 Internal 20 Perimeter 20 Intranet Link and Emails 75 Phi 100 108 Ir 100 Phicv 100 L Phreatic 76 Picture 79 Piezometric 76 105 Layers 103 Pile 1 7 73 93 132 Level 103 105 Pile Capacity 1 Limit State Approach 18 Pile Depths 1 Limiting End Bearing 12 Pile Geometry 92 Limiting Shaft Friction 9 Pile Wall 12 Limiting Value 100 Plot 128 Limit state 1 132 Plugged 93 Copyright Oasys 1997 2014 6 Pile Oasys Geo Suite for Windows Plugged Capacity 14 Porewater 1 Program Features 1 Properties 93 R Reduction Factor 93 Relative Density 10 Results 125 HGB 79 S Settlement 16 Shat 18 Shaft Diameter outside 96 Shaft Friction 8 Shaft Resistance 1 132 Shaft Wall Thickness 96 Shear 8 SI 79 Skin Friction 97 100 Skin Friction Computation 20 Soil Plug 12 Soil Strength 98
103. rrent end bearing force z is the pile base displacement at load reversal p j corresponds to the load reversal point RH is a curve fitting constant for the unloading curve R is a curve fitting constant for the reloading curve R is a curve fitting constant for the base is the degradation factor for the reloading curve p is the limiting end bearing force rj is the radius of the pile Gmax IS the initial shear modulus of the soil E ay IS the initial Young s modulus of the soil vis the Poisson s ratio of the soil 2 2 2 3 3 Logarithmic Curves Shaft curves In the case of cyclic loading the program keeps track of the elastic and irreversible deformation in the soil spring As long as the cumulative absolute irreversible displacement is less than the monotonic irreversible displacement to peak force there is no degradation of the peak force in either tension or compression However when the accumulated irreversible displacement exceeds monotonic irreversible displacement then degradation of peak force occurs The program deals with the pre peak behaviour and post peak behaviour separately First the pre peak behaviour is discussed Pre peak behaviour When the spring is in the pre peak zone it unloads parallel to the linear elastic segment Even when the spring is in the pre peak zone when the cumulative absolute irreversible displacement exceeds the monotonic irreversible displacement required to mobilise peak force in a
104. s to model the pre peak portion of the curve outlined in API 1993 The curve exhibits decreasing stiffness till peak followed by softening behaviour The user needs to enter the residual force as a fraction of the peak force to fully define the curve Copyright Oasys 1997 2014 E NN Pile Oasys Geo Suite for Windows F Peak Force Displacement For base interaction there is only one type of curve same for both clay and sand This is modeled by 5 points as specified in the API documentation Copyright Oasys 1997 2014 Method of Analysis 51 Force T i Displacement Notension in base spring 2 2 2 1 5 Emperical Vijayvergiya For the shaft the t z curve is parabolic The equation for the t z curve is given by When z lt Zo F E 2 LN Z zy When z 2 Zo Copyright O Oasys 1997 2014 52 Pile Oasys Geo Suite for Windows 4 i Farce Displacement For the base the tip load curve is given by When z Zs Copyright Oasys 1997 2014 Method of Analysis l Force Displacement Notension in base spring 2 2 2 1 6 User defined When using this option the user is required to enter a series of points to define a multi linear force versus displacement curve This curve is extended symmetrically into tension region for shaft curves Copyright Oasys 1997 2014 NES Pile Oasys Geo Suite for Windows Force Displacement For the base curves too the user
105. specified as these are not available in the code The program uses these M2 values in end bearing skin friction computations Note The M2 parameters are used for certain design approaches e g DA1 Combination 2 and DA3 5 7 2 Drained Materials Each record in the Drained Materials table vew consists of the following items dais FIXED Drained Materials a O A AA es EA A E ee E am Bulk Material factor for IE friction data ipti computation pressure K Um Tage ener Y kN m kPa Pai 20 00 EDI RE Emir TEE pire REESE UNI ER Layer 20 00 Earth pressure 25 Elas Plas t z 1 gt MAI A General A Friction Bearing Enter material name Sr A a es ne ft BEA AAA eS Ss ARS E EA bearing data NN tati OS AA a kPa Berezantzev k B None lt Er specified No Elas Plas t z 1 Nq specified 50 00 0 00 Yes 20000 00 Elas Plas Tip Load 1 m Copyright Oasys 1997 2014 input Data 301 Material description brief descriptions for each of the material types can be entered here Bulk unit weight bulk unit weight of the soil layer Material factor for soil strength the material factor that needs to be applied to cohesive strength or friction angle depending on type of material When the Working load method is selected in the Analysis Options the Material factor for soil strength field is greyed out completely
106. splacements table view is accessible by double clicking Applied Loads amp Displacements in the Gateway or via Data Applied Loads amp Displacements on the program menu opecify any thermal and or cyclic loads in the Thermal and Cyclic Loading dialog This is relevant to only settlement analysis This is accessible by double clicking Thermal and Cyclic Loading in the Gateway or va Data Thermal amp Cyclic Loads on the program menu If the Mindlin option for calculating displacements is used specify the radial distance from the pile at which soil displacements are to be calculated in the Displacement Radii table view This table view is accessible when settlement analysis is selected in the Analysis Options dialog The Displacement Radii table view is accessible by double clicking Displacement Radii in the Gateway or va Data Displacement Radii on the program menu opecify convergence control data in the Convergence Control Data dialog This dialog is accessible when settlement analysis is selected in the Analysis Options dialog The Convergence Control Data dialog is accessible by double clicking Convergence Control Data in the Gateway or via Data Convergence Control Data on the program menu If there are multiple stages of analysis create new stages and enter stage specific data as outlined in Stage tree view Perform an analysis by clicking the Analyse button on the Pile toolbar or va Analysis Analyse
107. subtracted so that min pile movement mm Poulos 19 See FEE Analysis Options Applied Loads amp Displacements isplacement Fr Design method Working load re compression calculations enabled Yes Is global FoS criterion for compression active Yes Global factor on ultimate bearing capacity Fg 5 0000 Output Is partial FoS criterion for compression active Yes l Partial factor on ultimate skin friction Fsl 4 0000 Partial factor on ultimate end bearing Fb 3 0000 WorkingLoad pls Graphical Output Soll profile 1 w zs Cross section 1 iv v 13 00 m Sy E x C m OF ifr eO T udi ra TIE d foc Ry fpes Dep h below ground leuel m zum Sex 44892 y 1767 Capad ly kN Working with the Gateway The Gateway gives access to all the data that is available for setting up a Pile model Top level categories can be expanded by clicking on the symbol beside the name or by double clicking on the name Clicking on the symbol or double clicking on the name when expanded will close up the item Double clicking on an item will open the appropriate table view or dialog for data input The greyed out items in the gateway are disabled Copyright Oasys 1997 2014 About Pile 3 1 3 2 Preferences This dialog can be accessed by clicking Tools Preferences Preferences can be set whether a file iS opened or not The Preferences dialog is accessible by ch
108. tails of the following should be gathered e the drained undrained parameters of the different soil materials at the proposed site e ground water data phreatic surface location and piezometric pressure distribution elevations if needed soil layer levels geometry of the pile and cross section information and depth of the pile Copyright Oasys 1997 2014 5 input Data Input Data Data is input via options that are available in the Data menu or via the Gateway E Pile 19 5 Settlement calc Sq pl Analysis Tools Graphics Window Help Units Titles Analysis Options Capacity Data File Edit View OB kdl E Input Settlement Data zz LI Pile Properties Analysis Opi Material Properties i e Capacity Dg Y Soil Profiles Settlement calc Sq pls Graphical Output Pile Proper V Groundwater Soilprofile1 Cresesecioni 20 00m E Material P Eu Soil Profiles Groundwater Map T m X Cy fine of i Doc mnl heal El de d de PE R R i ES Undrain Effective Stress Profiles i Drained f i T Sol Profiles Nq Phi Curves dl Pe n t z Curve Data 10 00 2 Limiting shaft skin friction D E gl p Tip load Curve Data 8 000 Layer pe Tecuve a cB f Beta gt 2500 ded Eu Ng Phi Cur Applied Loads or Displacements catia i Nonline Te load d t z Curve Di MPO GRAS ASS UE poet ee A EU an rib i Dis
109. tant R constant 5 Description pou oss PATE op M gd OA Chin Poulos Tip Load amp 0 000 0 300 100 Chin Poulos Tip Load 1 10000 000 0 300 1 000 1 000 1 000 1 000 a 4 m p Cell A 2 Description the name of the curve Young s modulus E Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows Top the Young s modulus at the top of the soil layer Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio value of the material Hyperbolic curve fitting constant R the hyperbolic constant for pile base element Unloading curve fitting constant R the curve fitting constant for the unloading curve Reloading curve fitting constant R the curve fitting constant for the reloading curve Degradation constant the secant modulus degradation value due to cyclic loading 5 14 3 Logarithmic Each record in the Logarithmic tip load Curves table view consists of the following items EE Pilel Logarithmic tip load curves e A B C D Young s modulus E Poisson s Description T ratio Y Defaults Defaults Logarithmic Tip Load H pb OOo d Cell A T1 Description the name of the curve Young s modulus E Top the Young s modulus at the top of the soil layer Gradient the rate at which the modulus changes down the layer Poisson s ratio the Poisson s ratio
110. tap below the tap of the highest sail layer Single pile length If checked then capacity and settlements are calculated for one pile length only Minimum pile length the minimum pile length for which the pile capacity to be calculated Maximum pile length the maximum pile length for which the pile capacity to be calculated Number of increments the number of increments between the minimum and maximum pile depth for which the pile capacity is to be calculated Quantities like skin friction plugged capacity etc do not vary linearly with depth The accuracy of such calculations can be improved by choosing a sufficient number of increments Copyright Oasys 1997 2014 9 Pile Oasys Geo Suite for Windows Depth of pile top below the top of the highest soil layer is the difference in height between the highest soil layer and the top of the pile If this value is positive it is used to represent basement piles If this value is negative it is used to represent general and local scour if the water table is above ground level 5 6 3 Pile Cross section Dimensions The Pile Cross section Dimensions dialog presents the following input data Pile Cross section Dimensions Units of cross sechon dimensions B C D Flange Web Flange Web width depth thickness thicknes Defaults Saar 1 00 1 00 0 10 0 10 1 50 1 50 0 15 0 15 1 50 1 50 0 20 0 20 Multiple cross sections can be entered one per row of the tabl
111. tch the signs of the Young s modulus values that were assumed for that analysis Iteration e However if a segment is continuously oscillating between tension and compression after many iterations the solver defaults its value to the Young s modulus in compression and a warning is given Copyright Oasys 1997 2014 Pile Oasys Geo Suite for Windows NOTE In models with thermal loading ONLY Young s modulus in compression is used i e the program does not consider different Young s moduli in tension and compression 2 2 4 Staged Analysis and Cyclic Loading When the t z curves option is selected a series of analysis stages that follow each other can be defined In addition cyclic thermal and mechanical loads can be defined in a particular stage Stage 0 Load to 1000 kN Stage 1 Load to 1500 kN Stage 2 Load to 2000 kN Stage 3 Unload to O kN During analysis when the program encounters a stage that has cyclic loading specified for N cycles it generates 2N 1 sub stages as shown below Copyright Oasys 1997 2014 Method of Analysis Cyclic sub stage N cycles Half cycle 2 Half cycle 2N sub stage sub stage S _ _ _ _ _ _ 2 N sub stages The transient sub stage is inserted to explicitly apply non cyclic loading component of the original loading stage Then in the subsequent sub stages additional cyclic loads are applied Transient
112. te for Windows Don TE Capacity Notes s Analysis options Pile properties Effective stress profiles Undrained materials Drained materials soil profiles Groundwater Nq Phi curves Applied loads amp displacements Capacity results Settlement Calculated limiting shaft skin friction t z curves Tip load curves Displacement radii Convergence control data Settlement results summary Stresses amp displacement along pile Soil displacements Calculated t z curves for each node Detailed cyclic results The results are provided in a tabular form containing the levels corresponding to the depth s of the pile and the various load capacities at the given level The results are printed for all the soil profiles However for model pile procedure the design capacity results are printed separately after the ultimate capacity results etc are printed from all the soil profiles The pile limiting shaft skin friction shaft skin friction pile stress pile and soil displacement at the given level are tabulated for each pile length and each cross section and for each load increment The number of outputs of calculated limiting shaft skin friction within a layer can be selected in the Print Selection dialog The analysis warnings may also be viewed in the results Copyright Oasys 1997 2014 Manual pls Tabular Output Cross section 1 results Results Compression Level m0D 4 0000 2 0000 1 0000
113. th the data file LH uantity Conversion Factor D isplacement 1000 per m Force 0 001 per M Lenath level perm Mass 0 001 per kg Stress 0 001 per Fa Reset Units Default options are the Syst me Internationale SI units KN and m The drop down menus provide alternative units with their respective conversion factors to metric Standard sets of units may be set by selecting any of the buttons SI KN m kip ft kip in Once the correct units have been selected click OK to continue Copyright Oasys 1997 2014 NA Pile Oasys Geo Suite for Windows SI units have been used as the default standard throughout this document 5 3 Analysis Options The following general data is entered to define the outline of the problem and type of analysis to be carried out Analysis Options Analysis type I Capacity Settlement Effective stresses Calculated User defined Datum information Elevation Depth below ground level Tona Analysis type Type of analysis can be selected either Capacity or Settlement or both If only Capacity analysis is selected then the data input for Settlement will be disabled and vice versa Effective Stresses Either of the following options can be selected Calculated the effective stresses in the soil layers are calculated by the program User defined the effective stress profiles both vertical stress profile and horizontal
114. trol Data Stage tree view Output Tabular Output Graphical Output The current stage index is displayed in the Stage indicator located at the bottom right corner of the application window The Stage data menu allows the data to be modified for individual stages using the Stage Operations window This opens a tree diagram which allows access to all available options for each stage Ticks are placed against those options which have been changed This window also allows the creation of new stages and the deletion of those no longer required When Add stage is selected the new stage can be inserted after a highlighted stage Parameters can also be set to change in a particular stage Note Left click on the boxes to open or close the tree diagram for each stage The dialog or vew corresponding to stage specific data i e Soil profiles Applied loads amp displacements etc can be accessed either from this tree view or from the gateway The program calculates the pile capacity and settlement for each stage based on whether the user has selected capacity analysis or settlement analysis For the settlement analysis the program treats the pile and soil displacements obtained from analysis of a particular stage as the initial displacements for the next stage The initial t z curves are generated and used for the first load increment of the initial stage The program updates the t z curves for each node after each load increment Whe
115. ulative skin friction is always exclusive of negative skin friction The negative skin friction is not taken into account when calculating the tension capacities and and in Design Resistance option 2 1 2 End Bearing Two basic methods are available total stress and effective stress based The former is appropriate to clays and soft rocks and the latter to cohesionless soils and clays for long term loading where the stress conditions are likely to change 2 1 2 1 Total Stress Approach In this approach end bearing stress q is given by E NC where N the bearing capacity factor for cohesion For solid piles N 9 for embedment of over about 2D where D the diameter of the Pile In the case of shallow embedment lt 2D N is taken as zero and a warning to this effect is generated For hollow sections or H piles the pile wall acts more like a deep strip footing therefore N 6 is more appropriate 2 1 2 2 Effective Stress Approach In this approach end bearing stress q is given by N o where o the vertical effective stress at the base of the layer being considered N the bearing capacity factor for surcharge and friction The following methods may be used to calculate No 1 N specified Copyright O Oasys 1997 2014 Method of Analysis 11 The value of N can be user specified li N calculated based on friction angle The most commonly used method to assess N is that
116. umption that all elements are elastic From these displacements the shear stresses are calculated and are then compared with the specified limiting stresses At an element say element i if the computed skin friction Dj exceeds the limiting value I the extra displacement caused by the out of balance force is calculated and is added to the previous elastic solution The shear stresses are then calculated again based on the modified displacements The procedure is repeated until all the computed shear stresses do not exceed the appropriate limiting shear stresses Downward drag or gap between pile base and soil correction If there is a gap between the pile base and the soil beneath then Pile ignores the force due to end bearing and iterates until force equilibrium and displacement compatibility are achieved Correction of Soil Stiffness Copyright Oasys 1997 2014 EE NN Pile Oasys Geo Suite for Windows To allow for the two different soil stif nesses above and below the pile toe an approximate treatment is included in the program The elements of the flexibility matrix 6 consist of two components Su Gy lEn Su Spi EL where Obj Ej displacement at the pile toe in the soil with E due to a unit load at element i 0 S pj E relative displacement between i and b in the soil with E due to a unit load at element 1 where Fij is the smaller of e a and M ji Ez 6 Es in which
117. urves e Logarithmic curves e Chin Poulos curves The cyclic loading behaviour for these different cases is discussed next 2 2 2 3 1 Default Behaviour All types of t z curves and tip load curves are updated after each loading stage to take into account load reversal and post yield behaviour Internally all the different types of curves are modelled as multi linear force displacement curves For the Chin Poulos curves and logarithmic curves the equations of the curves for initial loading unloading and reloading are explicitly given by equations For all the other types of curves the following assumptions are made to generate curves to account for yielding and load reversals The Non softening curves are discussed first e Only the first segment is considered to be the elastic segment This holds for both tension and compression cases e When the spring is loaded beyond the first yield point plastic deformations are introduced The unload curve in these cases are obtained by unloading parallel to the initial elastic segment This is similar to and an extension of the elastic perfectly plastic case The illustrations are given below Copyright Oasys 1997 2014 Method of Analysis i my qu my a aq Y D 5 F S LL OQ p ho ME Oa ie i D s S a F Lj F S3 P i Displacement As a result all the points on the unloading side of the curve shift parallel as shown below Copyright Oasys 1997
118. yright Oasys 1997 2014 Method of Analysis 19 Unplugged condition internal soil level changes with driven pile depth e R is obtained by calculating bearing capacity only over the wall area e RH is obtained by adding the contributions of external skin friction and internal skin friction with the internal soil level not necessarily at ground level Plugged condition e R is obtained by calculating bearing capacity only over the wall area and the plug area e R is obtained by considering only the external skin friction For both hollow and solid piles in tension Ra Bad sega where R characteristic shaft resistance The internal skin friction is ignored for hollow piles in tension y shaft resistance factor in tension Yay model factor tension Depending on the load case under consideration the characteristic resistances may or may not be determined using partial material factors However presently partial material factors are always applied when Design Resistance option is chosen When calculating pile capacity it is important to note that the calculated bearing resistance is neither an allowable working load or an ultimate capacity and must be compared with the appropriately factored combination of applied loads dependent on the design case being assessed The negative skin friction is treated as an action and is not included in the calculation of design resistance i e it is not subtracted

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