stapile3 - Stewart Technology Associates
Contents
1. Dr 50 If u lt 30 Dr 65 If u lt 45 Dp 85 If u gt 45 Dp 85 For cohesive soils np is taken from Figure 5 3 3 in Reference 2 Polynomials are fitted to the two curves in that figure The curve for soft clay is used if the average undrained shear strength for the clay is 1000 psf or less The curve for stiff clay is used if the average undrained shear strength of the clay layer is greater than 1000 psf For each soil layer the value of Dp is computed and a value for the pile soil relative stiffness T is computed by the equation T EI N A weighted average for T is then computed for the embedded length of the pile based upon the individual values for T for each of the soil layers in which the pile is embedded The value of pile length divided by soil stiffness is reported L T If this value exceeds C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 15 3 5 a warning is given by the program to the user that the short pile criteria may be exceeded This is a non fatal warning and the program will still continue 8 2 Vertical Loads Skin friction along the pile is calculated in each of the soil layers API methods Reference 1 are used The shaft in cohesive soil layers the shaft friction f is calculated by the equation 6 4 2 1 from Reference 1 f ac Where a is a2. applied to the pile the end bearing resistance of the pile will be calculated 8 1 Stiffness Factors Although the program assumes that the pile behaves as a short rigid unit a stiffness check is performed and a warning is issued if the pile appears to be too flexible compared to the soil stiffness for the case being analyzed The program calculates an average stiffness factor for the pile based upon the stiffness of the pile El value and the compressibility of the soil The soil compressibility is expressed in terms of a soil modulus which is not constant for any soil type but depends upon the width of the pile and the depth of the particular loaded area of soil being considered The soil stiffness is found by the program in terms of the coefficient of subgrade reaction nh The coefficient np is determined for a user selected value of the ratio Ymax divided by D the pile diameter The method used is that contained in the Navy Handbook For Marine Geotechnical Engineering Reference 2 For cohesionless soils Nh is obtained from Figure 5 3 2 in Reference 2 The program contains polynomial expressions which have been fitted to the four curves in this figure each of which is for a different soil relative density Dp The relative density of the soil is estimated by the program based upon the friction angle of the soil specified for a particular layer by the user The following selection criteria are used If u lt 5 Dy 35 If u lt 20
3. at the pile pad eye Units are kips If the pile is to be analyzed for uplift capacity this term will be positive If the pile is to be analyzed for vertically downwards applied loads this term will be negative This term is input by the using by clicking on the button Select Analysis Type and Apply Loads Note that if the User has selected to analyze suction embedment Hmax see above will be set to zero and Vmax will be set to the calculated load required to cause suction embedment pile mass densit Ib cuft This is the mass density of the pile material Units are pounds mass per cubic foot This term is used to calculate the submerged weight of the pile no radial bulkheads The User may specify as many radial bulkheads as desired If the User specifies zero there will be no radial bulkheads If the User specifies a value a 2 the program will assume that there is a central vertical bulkhead extending across the diameter of the pile If the User specifies 3 the program will calculate three radial bulkheads spaced as 120 degrees If the User specifies 1 the program will assume that vertical stiffeners within the pile exist For each of the radial bulkheads or stiffeners the program will calculate weight increased tip resistance to penetration and internal skin friction pile top thickness in This term is the thickness of a top which the User may specify on the pile Units are in inches The top will contribute weight to the pile Th
4. per square foot cu4 undrained sh strength bottom 2nd layer psf Comments as for cu2 apply cu5 undrained sh strength top 3rd layer psf C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 Appendix 1 PAGE 3 Comments as for cu1 apply cu6 undrained sh strength bottom 3rd layer psf Comments as for cu2 apply Note that if the pile is specified as being embedded with its bottom beneath the third soil layer the soil strength and weight parameters at the bottom of the third layer will be continued downwards Gamma 1st layer buoyant weight pcf This is the submerged or buoyant weight of the soil in the first layer Units are in pounds per cubic foot Gammaz2 2nd layer buoyant weight pcf This is the submerged or buoyant weight of the soil in the second layer Units are in pounds per cubic foot Gamma3 3rd layer buoyant weight pcf This is the submerged or buoyant weight of the soil in the third layer Units are in pounds per cubic foot Fy Yield stress for pile steel ksi This is the yield stress for the pile material This term is used in calculating a unity stress check for the pile considering the combined effects of axial and bending stresses ztop top to seabed ve if buried ft This is the distance of the pile top to the sea bed Units are in feet If the pile top is at
5. to the bottom of the pile The program will issue a warning if the pile extends below the bottom of the third layer specified by the User Phi1 1st layer friction angle deg This is the friction angle to be used in the analysis for cohesionless soil in the first layer Unis are degrees If the first soil layer is cohesive Phi1 should be specified as zero The program will issue a warning if both cohesive and cohesionless properties are specified for any soil layer Phi2 2nd layer friction angle deg This is the friction angle to be used in the analysis for the second soil layer Comments as for Phil apply Phi3 3rd layer friction angle deg This is the third layer friction angle Comments as for Phi apply cul undrained sh strength top 1st layer psf This is the UNDISTURBED undrained shear strength for the soil at the top of the first layer in other words at the sea bed Units are in pounds force per square foot cu2 undrained sh strength bottom 1st layer psf This is the UNDISTURBED undrained shear strength for the soil at the bottom of the first layer in other words at the sea bed Units are in pounds force per square foot The undrained shear strength is considered to vary in a linear manner between the top and bottom of each layer cu3 undrained sh strength top 2nd layer psf This is the undrained shear strength for the soil at the top of the second layer in other words at the sea bed Units are in pounds force
6. 0 4 14 28 2000 4000 05 50 65 over 4000 oa 50 65 FIGURE 9 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 13 Table 6 4 3 1 from API RP 2A 20th Edition 1993 Design Parameters for Cohesionless Siliceous Soils Sail Pile Fr ction Limiting Skin Ange delte Friction Values De 8 8 12 12 20 20 Afi 44 50 od dnmg pertormance is avatahe other wiles maybe justited tractons Limiting Linit End 3eering Values SEES kPa Nic kips saft MPa A0 1 9 40 40 60 60 60 10C 10C 200 20C 25C i 25C 12 0 The parameters ited n thistabk are imended ascuidehhes Sand Skindudesthese wik with signricant fractions of only Where detaled nformmacion a ch asin stu cone tests both sand and st Strength valves generallyncrease mt drength tests on righ cualtysampes rmdel tests or ple increasng sand fractions and decease sth ncreasng dt FIGURE 10 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 14 8 0 BASIC ANALYSIS ASSUMPTIONS The user can be reminded of the basic analysis assumptions when running the program by clicking once on the button assumptions Ia vertically downwards load is
7. E 17 8 3 Ultimate Resistance To Horizontal Loading The method of Brinch Hansen is used to calculate the ultimate lateral resistance of the pile inasmuch as the pile is divided into around 50 elemental lengths This number varies depending upon whether the pile is completely buried or has any of its length above the soil Each elemental length is treated as a rigid unit The maximum passive resistance for each rigid unit however is not found using Brinch Hansen s coefficients but is found using API coefficients Reference 1 This section of the manual reproduces equations from API RP 2A using the same equation numbers as in that document Reference 1 Cohesive Soils The ultimate lateral bearing capacity py of clay is varied between 8c and 12c except at shallow depths where failure occurs in a different mode due to minimum overburden pressure Cyclic loads caused deterioation of lateral bearing capacity below that for static loads In stiff clays c gt 2000 psf more rapid deterioation under cyclic loading is expected according to Reference 1 The following equations taken from Reference 1 are implemented within STA PILES Du increases from 3c to 9c as X increases from 0 to Xp according to Pi SSC OKI ege 6 7 2 1 and Pu 9c for X gt Xp tetatneaetanal tees cheaeataheauernneatice 6 7 2 2 where Pu ultimate resistance psi c undrained shear strength for undisturbed clay soil samples psi D pile diameter in y ef
8. ERETAS ENE ENETEIA TEN NEE ENAREN 15 8 3 Ultimate Resistance To Horizontal Loading eee a 17 Cohesive SollS a E EA E A EE A E EEE E E EE 17 oaa EEEo eE E E EE 17 Ee Ee 18 Rotational Failure CGalculatons 18 9 0 PILE STRESSES EEN 20 REFERENCES 220 0 e ce ceccceccceccecccecceceeeececceecaeeceecaeeceeceecaueceecaeeceeceeaueceecauecsecteeseeeeeeaeeaeeeaes 21 APP ND See Sh ie ee Dee ee Se ee ee DEFINITION OF INPUT DATA C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 1 1 0 INTRODUCTION STA PILES is a program for the design and analysis of piles with a free head condition The program determines the ultimate capacity of the pile in response to a combination of vertical and horizontal loading Being an ultimate capacity approach the program does not consider deflection limitations Those who wish to determine piles suited to conditions which must have limited deflections should use another approach STA has programs for this and inquiries are welcomed The general approach in STA PILE 3 is that of the API Reference 1 The user may define up to three soil layers which may be either cohesive or cohesionless or with combined properties The basic version of the program is set up to handle cylindrical steel piles and the user must specify the pile properties These properties are yield stress pile lengt
9. PROGRAM or shall use the PROGRAM for any purpose at any time The use of the PROGRAM is not limited to a single machine and the USER may make copies of PROGRAM and run it on several machines simultaneously The USER agrees to make any reasonable effort to assure that the PROGRAM file or disk is not copied without authorization by OWNER and that all users in USER s organization are familiar with these Limitations of Use The USER agrees not to modify copy sell lease rent give free of charge or otherwise distribute or alter the PROGRAM or any part thereof to any individual government agency or organization outside of the USER organization COPYRIGHTS All copyrights to the PROGRAM are reserved by OWNER All versions of the PROGRAM are copyrighted by OWNER worldwide beginning with 1991 The following is a trademark of OWNER STA PILE3 The USER shall clearly and distinctly indicate the copyright in all published and public references to the PROGRAM WARRANTY While the OWNER has carefully developed the software and the software has been tested for accuracy and proper functioning nevertheless the OWNER cannot guarantee its accuracy and correctness If the software fails to perform correctly as a result of errors or omissions by the OWNER or its staff the OWNER will at its discretion rectify those errors and omissions free of all charges to the USER This shall be the limit of the OWNER s liability in this respect OWNER warrants that it h
10. STA PILE3 ANCHOR PILE DESIGN USING API RP 2A WITH SUCTION EMBEDMENT OPTION Version 1 6 October 1998 USER MANUAL STA PILE3 is a computer program for the design and analysis of pile anchors The piles are treated as being short with a free head condition The attachment point or padeye for the mooring line may be at any point on the pile The pile may be driven into the sea bed or may be embedded by suction The pile may be fully embedded partially embedded or may be driven deep beneath the sea bed STA PILE3 permits the user to soil layers each of which may have The layers may be a mixture of soils Primary results from the capacity of pile anchrs for vertical Additionally the program provides and provides an ultimate capacity and horizontal loading The calculate suction embedment conditions The differential pressure requred to embed a suction anchor is calculated and a warning is given if the plug inside the anchor will lift For cylindrical steel piles maximum axial and bending stresses in the pile are also calculated specify up to three different varying strength properties cohesive and _ cohesionless program provide the ultimate and horizontal loading factors of safety against failure check for combined vertical program may also be used to This program has been developed by Stewart Technology Associates STA All copyright for the software and documentation remains with STA Users of the program are cautioned t
11. anual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 7 W 1 6 Oct 1998 Runtet sactive Subs compact gravel at 23 20 a ALEENIN ES MI SNE anvards For EUY For pile top below sea bed make ztop aegatire zoil pile friction 3 thickness of lowest soil layer Ft angles vci i radial bulhead thickness in pile top thickness fin cu reduction factor stalled capacity analysi derconsol 2 normal Short pile criteria probable GK ult ult horiz capacity in ki Rotation center shown as blue dot ult alt vert capacity in kip Pile Elevation a max ax ctr from Ymax kb lager larr ing kip Feet am er MLL D an am am D D D m m Depth fin Depth fin m FIGURE 2 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 8 6 0 RUNNING THE PROGRAM Once you have set up the program using the instructions in Section 4 0 you will be able to click on the STAPILES icon to start Excel and STA PILE3 The main spreadsheet STAPILE3 XLS will load If you can see the button labeled Select Analysis Type and Apply Loads simply click once on this button You may need to maximize the spreadsheet Do this by clicking once on the negative sign in the upper left hand corner of the spreadsheet From the drop down menu that will appear click once on Ma
12. as the right to grant this license The PROGRAM and its documentation is sold as is and the USER assumes the entire risk as to quality and performance HOLD HARMLESS The OWNER shall not be liable to the USER or any other party for any design performance or other fault or inadequacy of the PROGRAM or its manual or for any direct or implied damages of any kind arising out of or in any way related to or connected with any use of the PROGRAM C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE iii CONTENTS LIST Subject Page 1 0 INTRODUCTION 00 c ccceccccccecccecceeceeccecceeeceececaeeceecaeeceeceeaeeceecaeeseecueeaeeseeeaeeseeeaees 1 2 0 FAILURE MECHANIGM 2 3 0 SPECIAL CONDITIONS AT PILE ANCHORG 3 4 0 PROGRAM INGSTALULATION 4 4 1 IMMFOGUCTION WEE E A 4 2 Install Files and Create Directories ccccccceccceccecececceeceeececcececeeceecaeeceseueeneeeaees 4 4 3 tU We DEENEN A 4 4 Program Files On Distribution Diskettes AA 4 5 0 HARDWARE REQUIREMENTS AND PRINTING 2 02 00cceeececceceeeececcececeeeecees 6 6 0 RUNNING THE PROGRAM 8 7 0 GETTING HELP 200 00 ec ccc ccccceccecceeccecceecceeceececceeceeeaeeceecaeeaeesseeaeeceecaeeaeecneees 10 8 0 BASIC ANALYSIS ASSUMPTIONS ccccccceccecceecceccececeeceeceeeceeceeeceeceeeaeeceeeaes 14 8 1 Stiffness Factors 14 8 2 Vertical Loade AE N
13. ay edit any of the cells in the input data section of the worksheet A full description of the meaning of all the terms in this section of the worksheet is contained in Appendix A Please note that the program uses iterative calculations to determine whether or not the pile is plugged if an open ended pile analysis is performed As soon as you have selected the analysis type the worksheet environment will be set within Excel to perform iterative calculations While the iterative scheme is relatively robust you may find that you can specify inappropriate input data which will cause the system to fail The failure will be manifested by error messages occurring in Results cells You should normally be able to rectify this situation by correcting your input data However it may be necessary to switch from a suction embedment analysis to an installed pile analysis and specify the pile to be closed ended Once you have corrected your problems of inappropriate data input the program should run successfully C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 10 7 0 GETTING HELP In Figure 3 two of the buttons are labeled Explain Highlight any data entry or results cell by clicking on it once and then click once on any Explain button A dialog box will be flashed up onto the screen containing information rega
14. bj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 4 4 0 PROGRAM INSTALLATION 4 1 Introduction STA PILE3 is a computer program for the design and analysis of pile anchors The latest release of the program Version 1 5 October 1998 runs in the environment of Microsoft Excel 97 or later under Windows 95 NT4 or later The program is distributed as a series of Excel workbook with macro files on a single 3 5 inch floppy disk This section of the manual provides instructions for loading the program and setting up the Windows icon 4 2 Install Files and Create Directories STA PILE3 must be set up in sub directory on your hard disk Before installing STA PILE3 you must have Excel already installed on your hard disk You must manually set up the necessary directory and copy the files over The manual procedure is as follows Create a sub directory for example called STAPILE All files from the floppy disk should be copied into the STAPILE sub directory You will then have a path to the program files as shown below X MY_PROJECTS STAPILE program_files In the example above X is the name of your hard disk most likely this will be C or D and the MY_PROJECTS directory may be where you store your projects 4 3 Install icon Once the directory structure has been created and the program files have been copied from the distribution floppy diskette to the STAPILE sub directory you can set up the
15. ces between pile anchors and free standing piles are noted here First the pile anchor is frequently buried beneath the sea bed Second the load applied to the pile anchor is generally from a mooring chain attached to the pile anchor by a pad eye The pad eye may be some distance below the top of the pile anchor Consequently the pile anchor induces passive soil resistance above the point of load application as well as below the point of load application The program accounts for the improved lateral resistance of fully buried pile anchors when the pad eye is at some distance beneath the top of the pile anchor Unlike foundation piles for many offshore structures that are generally long and slender anchor piles are generally stocky with comparatively slenderness ratios API Reference 1 and other design guidance documents authorities generally recognise that the horizontal resistance of a long slender offshore structure foundation pile largely comes from the upper sea bed soils The pull out resistance and the resistance to further embedment largely comes from the soil around the lower half of the pile Hence the two types of ultimate capacity can be treated virtually independently In short stocky anchor piles this is inappropriate and combined failures are to be considered rotation caused by horizontal loads and pull out caused by vertical loads C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLo
16. cy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 Appendix 1 PAGE 1 APPENDIX 1 DEFINITION OF INPUT DATA This Appendix lists each of the input data terms that the user may edit Note that by placing the cursor on any input data cell and clicking on the button EXPLAIN VALUE the User is presented with a dialog box containing a detailed description of the input data term This Appendix provides a reference for each of these terms C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 Appendix 1 PAGE 2 Z1 thickness of upper soil layer ft This is the thickness of the first soil layer from the sea bed downwards Units are feet Z2 thickness of middle soil layer ft This is the thickness of the second soil layer beneath the sea bed Units are feet Note that a visual check on the input data is provided in the upper diagram on the main results page for the program entitled Pile Elevation Z3 thickness of lowest soil layer ft This is the thickness of the lowest soil layer in the analysis Units are feet Note that if the bottom of the pile is defined as extending to a depth within the sea bed beneath the bottom of this lowest soil layer the properties for the soil at the bottom of the layer will be extended
17. depth still This program is for short rigid piles Length to width ratios should be less than 12 At the ultimate capacity load applied horizontally to the pile head the pile will rotate and fail the soil plastically A passive resistance develops above the toe on the opposite face of the pile adding to the resistance of the soil further up the pile towards the ground surface Failure occurs when the passive resistance of the soil at the head and the toe are exceeded i STA PILE BASIC ASSUMPTIONS AND ANALYSIS APPROACH The diagram ER shows the basic Failure mechanisms considered in STA PILE Horizontal capacity is governed by rotational failure as shown below vertical uplift capacity or embedment resistance is calculated Suction embedment may be specified in which case the program computes necessary suction pressure differential Piles must satisfy the criteria For short stiff piles Pile Ultimate Resistance Diagram center of pile rotation soil ultimate pressure diagram end resistance for downwards loading FIGURE 1 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 3 3 0 SPECIAL CONDITIONS AT PILE ANCHORS STA PILE3 is designed to take account of the special conditions associated with the design and analysis of pile anchors Several important differen
18. dimensionless factor and c is the undrained shear strength of the soil at the point in question The factor a is computed by equation 6 4 2 2 from Reference 1 a DW for w lt 1 0 a 0 5w for w gt 1 0 Both of the above equations have the contraint that a may not exceed 1 0 The variable w is equal to c p for the point in question where po is the effective overburden pressure at the point in question The alternative method for determining pile vertical ultimate capacity described in the commentary to Reference 3 may also be used If this method is desired the user should set the input variable Cgwitch to 1 and the shaft friction in cohesive soils will be calculated as follows For C to be less than or equal to donn F C For C in excess of 1 4 ton ft but less than or equal to 3 4 ton per square foot the ratio of F to C decreases linearlly from unity at C 1 4 ton ft to 1 2 at C 3 4 ton ft For C in excess of 3 4 ton ft F is taken as 1 2 of C Shaft friction in cohesionless soils is calculated by the method described in Reference 3 The shaft friction f is found from the equation f Kpotan d Where K is the coefficient of lateral earth pressure po is the effective overburden pressure and d is the friction angle between the soil and the pile wall The value of K is taken to be 1 in the program as the pile is assumed to be closed end The value of d is taken from Table 6 4 3 1 in Reference 3 The limiting
19. e User may adjust the thickness to account for additional equipment on the top of a suction pile The pile mass density is used in calculating the weight of the pile top cu reduction factor This term is used to multiply the undisturbed undrained shear strength of each layer A cu reduction factor of 0 5 means that the actual undrained strength of the soil used in resistance and pullout calculations will be 50 of that input by the User A cu reduction factor of 0 75 means that the actual undrained shear strength of the soil will be 75 of that specified by the User Suction embedment analysis In earlier versions of the program this switch had to be set by the User The term is now automatically set when the User clicks on the button Select Analysis Type and Apply Loads The User is given two options in a dialog box that will appear The first option is to perform and installed analysis The second option is to perform a suction embedment analysis This term will be set to 1 if suction embedment is selected or 2 if C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 Appendix 1 PAGE 5 installed analysis is selected If it is desired to determine the penetration resistance of a driven closed ended pile this switch should be set to 1 Where a closed ended pile is specfied the analysis will assume that the pile
20. e units shown in the input data section of the program Layered Soils Up to three soil layers which may be mixed cohesive and cohesionless layers can be specified by the user in STA PILE3 In each layer the above equations are implemented for each elemental length of the pile Overburden pressure is calculated for buried cohesionless layers Rotational Failure Calculations In order to calculate the failure mode of a pile anchor subject to horizontal loading the unit passive resistance of each element of the pile at a depth Z below the ground surface is given by the equation Pz PozKqz Chr Where Poz is the effective overburden pressure at depth z c is the cohesion of the soil at depth z and Kg and Kez are the passive pressure coefficients for the frictional and cohesive components respectively at depth z For each successive soil layer the depth z is assumed to begin at the top of the soil layer in order to determine the appropriate coefficient K or Ke However the effective overburden pressure is calculated from the top of the soil down to the depth of the layer in question The total passive resistance on each horizontal element dH is given by the equation C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 19 dH pzdHB The point of rotation of the pile is then found such that the s
21. fective unit weight of soil Ib in3 J Avalue of 5 is appropriate for Gulf of Mexico clays and is used in STA PILE3 although this can be user controlled if desired depth below soil surface in Ee Il Cohesionless Soils The ultimate lateral bearing capacity for sand has been found to vary from a value at shallow depths determined by Eq 6 7 6 1 to a value at deep depths determined by Eq 6 7 6 2 At a given depth the equation giving the smallest value of pu should be used as the ultimate bearing capacity C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 18 Pus C4 H C o D oyo H were 6 7 6 1 Dig C30 Doy A E 6 7 6 2 where p ultimate resistance force unit length beim s shallow d deep y effective soil weight bim H depth in A angle of internal friction of sand deg C4 C2 C3 Coefficients determied from figure 6 7 6 1 as function of A D average pile diameter from surface to depth in In STA PILE3 coefficients C4 C2 and C3 are determined based upon the user input angle of internal friction for the soil and by polynomial curve fits to Figure 6 7 6 1 in Reference 1 Note All units for user input terms in STA PILE3 are converted to appropriate values for use in the equations described in this section It is important that the user inputs values in th
22. h pile diameter pile wall thickness and Young s modulus for the steel In addition to analyzing the capacity of installed piles STA PILE 3 may be used to calculate the conditions associated with the installation of suction embedded piles Suction embedded piles are installed by causing a differential pressure between the inside of the pile and the surrounding water This differential pressure causes a net downwards force on the top of the pile Under certain conditions the pile will force itself into the sea bed C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 2 2 0 FAILURE MECHANISM The general failure mechanism assumed by the program is for the pile to rotate about some point within its length as a consequence of the lateral load or to pull upwards as a consequence of the vertical component of load applied to the pile These failure mechanisms are illustrated in Figure 1 below In the case for a vertical pile unrestrained at the head subjected to a lateral load at the pile head the lateral loading is initially carried by the soil close to the ground surface As the load at the pile head is increased the soil compresses elastically but the movement is sufficient to transfer some pressure from the pile to the soil at greater depth Eventually the soil yields plastically and transfers loads to greater
23. icon see your Windows documantation or simply right click on your desktop and be intuitive 4 4 Program Files On Distribution Diskettes Each distribution diskette for STA PILE3 is a self contained version of the program The files on your diskette should be as listed below File Name Description C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 5 STAPILE3 ICO Icon for STA PILE3 The icon is displayed by Windows Double click on the icon to start STA PILE3 after program is installed STAPILE3 XLS This is the main file displayed to the user by Excel All the data input is specified in this file All principle results are contained in this file Other files may be present on your diskette and the names of some of the above files may be changed slightly on some diskettes The STA PILE icon is shown to the right C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 6 5 0 HARDWARE REQUIREMENTS AND PRINTING STA PILE3 requires an IBM PC with Microsoft Excel 67 or later running under Microsoft Windows 95 or later environment The main spreadsheet is large approximately 550 Kbytes and a minimum memory of 16MB is recommended Program output has been custom
24. is filled with water both during driving and during pullout resistance calcuations If the User specifies an closed ended pile by setting this switch to 1 and then selects to perform a suction embedment analysis the program will issue a warning In the psi method the friction force is This term is a selection switch which sets alpha 1 0 in the calculation of pile skin friction using the API RP 2A 19th Edition psi method This effectively sets f cu which is appropriate for underconsolidated C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC
25. ized such that it prints all principal input and output on one page as shown in Figure 2 on the following page For best quality print it is recommended that a color ink jet printer is used with a minimum resolution of 300 dpi Significantly better quality will be obtained with a dot resolution of 400 dpi or above True Type fonts have been used throughout the worksheet Almost all the fonts are Arial Many of the fonts are Arial Narrow If you do not have these fonts on your machine the program will select the nearest font style It is recommended that you obtain the Arial Narrow font if it is not currently available on your system You may elect to print any of the output in color for example on a HP Deskjet printer If a color printer is used you may have to disable certain third party fontware such as Adobe Type Manager in order to get color text and numbers to print However once your printer is set up to print any other spreadsheets from Excel you should have no problem in printing output from STA PILE 3 You may have a higher resolution screen driver than VGA which is the minimum required for STA PILE3 in use on your system This will be advantageous in that it allows you to see more of the main worksheet than you can see with a VGA driver Most of the examples in this manual show screens with an 800 x 600 screen driver C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3M
26. load as shown in Figure 12 4 undrained sh strength bottom 2nd layer psf Explain value mei 2nd layer buoyant weight pe 0 25 t capacity unity check Meyerho mma3 3rd layer buoyant weight pef Short pile criteria probably OK Rotation center shown as blue dot Pile Elevation max ax st from Ymax ksi 5 eight of pile top kips for pile Ti Al multiplier on base shear TA O none layer 2 ermbedment lengthpile OD 110 71 layer 3 x ve BM from Hult f kip Explain value Select Analysis Type and or Change Applied Loads ee es orizontal Soil Reactions 10000 5000 1500 1000 0 100 200 300 400 Depth in 500 Depth in 600 FIGURE 12 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 21 REFERENCES 1 Recommended Practice For Planning Designing And Constructing Fixed Offshore Platforms API Recommended Practice 2A RP 2A 19th Edition August 1 1991 Handbook For Marine Geotechnical Engineering Technical Editor Rocker K March 1985 available from Naval Civil Engineering Laboratory Port Hueneme California 93043 Meyerhof G G and Ranjan G The Bearing Capacity of Rigid Piles Under Inclined Loads in Sand Vertical Piles Canadian Geotechnical Journal Vol 9 1972 pp 430 446 C Documents and Settings Lu
27. max applied lateral load kip E N it rie 199 Ymax applied vert load ve up kip underconsol 2 normal Explain value 24 35 Horizontal load safety factor 2 48 Vertical load safety factor 0 251UKt capacity unity check Meyerhof Short pile criteria probably OK FIGURE 6 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 11 The value for the ultimate capacity unity check UCUC is found From the Following UCUC CHiHult 2 i ult 2 x 1 5 Where H applied horizontal load Hult ultimate horizontal capacity in absence of vertical loading V applied vertical load Vult ultimate vertical capacity in absence of horizontal loading Tt can be seen that if H Hult and Mut then UCUC 3 0 If the Factors of safety For both horizontal and vertical Failures are both 1 5 then UCUC 2 x 1 1 5 2 1 33 If both vertical and horizontal factors of safety against failure are 1 73 the UCUC is equal to 1 0 The UCUC is one way of assessing the adequacy of pile anchors subject to combined loads FIGURE 7 If the user selects a cell for which there is no help available a dialog box will be flashed up on the screen suggesting that the cursor is repositioned in another cell An example of this is
28. o exercise experienced and careful engineering judgment when interpreting the results from STA PILE3 This is especially important with this program since results can be obtained in seconds on a modern PC This rapid speed and ease of use does not alter the care and attention needed from the user associated with selecting the appropriate geotechnical and loading conditions The program runs in the environment of Microsoft Windows and Microsoft Excel A mouse is used to click on option buttoms in order to move rapidly through the analysis A large number of Help screens are provided No experience of Excel is required to use STA PILES No part of this document should be taken in isolation or out of context and interpreted in a manner inconsistant with the overall framework and intent of this document STEWART TECHNOLOGY ASSOCIATES 5619 Val Verde Houston Texas 77057 Tel 713 789 8341 Fax 713 789 0314 e mail info stewart usa com 10 29 98 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE ii EXTRACTS FROM LICENSE AGREEMENT LIMITATION OF USE This License is granted to the USER for an indefinite period The USER agrees that no individual outside consultant government organization or any person who is not on permanent staff with the USER or under direct in house control of USER shall have access to the
29. pe of analysis you wish to perform The choices are nstalled Pile Capacity Analysis or Suction Embedment Analysis n this dialog box you will also be able to define the loads to be applied to the pile in an installed pile capacity analysis These loads will be retained in this dialog box and loaded into the worksheet each time you select the nstalled Pile Capacity Analysis option If you select to perform a suction embedment analysis these loads will still be retained in the dialog box but the horizontal applied load will be set to zero on the worksheet and the load necessary to C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 9 cause suction embedment will be calculated as the vertical applied load An example of how this dialog box looks is shown in Figure 4 STA PILES A PROGRAM FOR THE DESIGN AND ANALYSIS OF PILE ANCHORS Select the form of analysis to be performed by clicking one of the option buttons below Cancel Installed pile capacity analysis C Suction Embedment Analysis Define loads to be applied in input boxes below 251 3 Horizontal Applied Load kips 198 5 Vertical Applied Load kips positive load is applied upwards Loads will only be used if installed capacity analysis is selected FIGURE 4 Once you have set the analysis type you m
30. rding the selected cell An example of this is shown in Figure 5 In this figure the user has selected the input cell cu_switch A dialog box has been brought up onto the screen describing what this input data selection switch does This term is a selection switch which determines if the skin Friction is to be calculated by the 4PI RP 24 nineteenth edition psi method or if the old API method described in the commentary should be used In the psi method In the old API method friction f alpha x Cu Fa CU for Cu lt 0 25 ton saft alpha 0 5 x psi 5 For psi lt 1 0 F 0 5xCu for Cu gt 0 75 ton saft alpha 0 5 x psi 25 for psi gt 1 0 4 linear variation of E with Cu is used between psi Cujpo the above values of Cu pO effective overburden pressure at point in question It is simple to investigate the difference between results obtained by either method simply by changing this particular term FIGURE 5 Help is also available in interpreting the results The main summary results for an installed pile analysis are seen in the lower right hand corner of Figure 2 In Figure 6 an enlarged view of a section of Figure 2 it is seen that the ultimate capacity unity check results cell has been selected The dialog box that appears when the Explain button is clicked is shown Figure 7 and explains the basis of this result 1 cu _switch 1 si 2 0ld API method 257 iH
31. shown in Figure 8 No help available for this cell Place cursor in a data input cell or in a results value cell then click on explain button OK FIGURE 8 Two tables of useful data are built into the program and can be viewed by clicking on the API Cohesionless Soil Parameters button or the Navy Soil Design Parameters button The tables are shown in figures 9 and 10 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 12 Table 5 3 1 From Navy Geotechnical Handbook Properties of Cohesionless Soil Useful in Pile Design SE Standard friction relative buoyant Penetration angle density unt w eight Type Blow Count N degrees percentage oct medium dense 10 30 30 36 35 65 55 65 Copyright Stewart Technology Associates 1992 and onwards For support telephone 713 782 8341 or fax 713 782 0314 Table 5 3 2 From Navy Geotechnical Handbook Properties of Cohesive Soils Useful in Pile Design undrained shear strength buoy ant SU epsilon50 unit w eight Typ percentage pcf S underconsolidated clays 0 35 1 0 ge J90 ae te aa soils at depth z inches 1 0 0 00332 144 5 7z ft 25 50 d 7 2 1 overconsolidated soils based on consistency medium stiff 3 5 70 500 1000 1 50 65 stiff 70 14 1000 2000 0 7 50 65 0 0 5
32. the sea bed this term will be zero If the top of the pile is above the sea bed this term will be a positive value If the pile top is driven beneath the sea bed this term will be negative zc dist pile head to pad eye ft This is the distance in feet from the top of the pile to the pad eye If the pad eye is at the top of the pile this term will be zero pile OD in This is the outside diameter of the pile specified in units of inches t pile wall thickness inches This is the thickness of the pile wall in inches The pile is assumed to have uniform wall thickness throughout its length All piles are modeled as uniform cylinders E Young s Modulus pile psi This is the Young s Modulus for the pile material Units are in pounds force per square inch A typical value for steel is 30 000 000 psi A typical value for concrete is 3 500 000 psi This term is used in calculating the relative pile soil stiffness term see below C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 Appendix 1 PAGE 4 Hmax applied lateral load kip This is the horizontal applied load to the pad eye Units are kips This term is specified by the user in a dialog box which is activated by clicking on the button Select Analysis Type and Apply Loads Vmax applied vert load ve up kip This is the applied vertical load
33. ummation of the passive soil resistance forces times their lever arms above the point of rotation balances the sum of the element passive resistances multiplied by their lever arms below the point of rotation Having found the depth to the center of rotation from the above approach the ultimate lateral resistance of the pile to a horizontal force is obtained by taking moments about that point of rotation The program then constructs shearing force and bending moment diagrams The bending moments shear forces and soil reaction diagrams are reported on the single page of output which would normally be printed by a user of the program C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 20 9 0 PILE STRESSES Having found the bending moments in the pile the program calculates bending stresses and reports the maximum bending stress in response to the ultimate horizontal load that the pile can resist The program also reports the bending stress in response to the user specified applied horizontal load Additionally the program reports axial stresses in response to the vertical loads The program determines the ultimate vertical upwards load that the pile can carry and the maximum axial stress that this will cause It reports this value as well as the maximum axial stress in response to the user specified vertical
34. values for f given in this table are also applied in STA PILES If the vertical component of loading applied to the pile is upwards shaft friction on the outside of the pile only is considered However if the vertical loading is downwards STA PILE8 considers internal shaft friction if the pile is specified as open ended or the end bearing of the plug whichever is less as well as the end bearing of the pile wall C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAGE 16 annulus If the pile is specified as closed end the end bearing of the full cross section is calculated The equations for end bearing are taken from API RP 2A Reference 1 with coefficients and limiting values from Table 6 4 3 1 in this reference The user of STA PILES is cautioned to use care in selecting the soil properties for analysis The user is advised to consult Reference 1 The user can see a graph of skin friction down the pile by clicking once on the Friction button An example is shown in Figure 11 below Inactive Subs compact gravel at 40 ft 499 Vmax applied vert load ve up kip Vertical Joad safety factor FIGURE 11 C Documents and Settings Lucy HAL 9000A My Documents My Web Sites stewart usa com www HTMLobj STAPile3Manual STAPILE3 DOC STA PILE3 VERSION 1 6 October 1998 PAG
35. ximize Your start up screen should then appear as shown in Figure 3 v 1 6 Oct 1998 Run ref inactive Subs compact gravel at 40 ft 10 28 98 20 30 Copyright Stewart Technology Associates 1992 and onwards For support telephone 713 789 8341 or fax 713 7820314 Select Analysis Type and Apply Loads _ Assumptions Friction Print Input amp Results API Cohesionless soil design parameters For pile top below sea bed make ztop negative SO PROPERTIES up to three layers soil pile friction 23 thickness of lowest soil layer D angles p A p top to seabed ve if buried ft 1 radial bulhead thickness in Phi3 3rd layer friction angle deg SI ji pile wall thickness inches 2 iInstalled capacity analysis cu2 undrained sh strength boom 1st layer psf ax applied lateral load kip 1 cuswitch 1 psi 2 old API method max applied vert load Love up kip derconsol 2 normal 4 undrained sh strength bottom 2nd layer psf cud undrained sh strength top 3rd layer psf 24 35 Horizontal load safety factor Explain value ammas 3rd layer buoyant weight pef FIGURE 3 The spreadsheet will always contain values in every editable cell It is recommended that following an analysis with the program you save the spreadsheet before closing down the application You should begin each new analysis by clicking on the button Select Analysis Type and Applied Loads A dialog box will open in which you can select the ty
Download Pdf Manuals
Related Search