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है”ह”ह

IS 2911-4 (1985): Code of practice for design andconstruction of pile foundations, Part 4: Load test onpiles [CED 43: Soil and Foundation Engineering]

Gr 5

IS : 2911 ( Part 4 ) - 1985( Reaffirmed 2010 )

Indian StandardCODE OF PRACTICE FOR

DESIGN AND CONSTRUCTION OFPILE FOUNDATIONS

PART 4 LOAD TEST ON PILES

(First Revision)

Sixth Reprint JULY 2003

UDC 624.154.1: 624.042 : 006.76

Copyright 1985BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

September 1985

IS I 2911 ( Part 4 ) -1985

Indian StandardCODE OF PRACTICE FOR

DESIGN AND CONSTRUCTION OFPILE FOUNDATIONS

PART 4 LOAD TEST ON PILES

( First Revision)

Foundation Engineering Sectional Committee, BDC 43

C/l4irman~IA.J·G~N 011uru SIJroJI

Rtprtstnling

~linistr~' of Defence

SBBI A.. N. JA~GLE ( Alt"n,,', )

M,mlJ"sCOL K. P. A".~~J) ( Alt,rnate to

Maj-Gen Ombir Singh)S,iIH D. ANJIAH A. P. Engineering Research Laboratories, HyderabadSKRI Aa.""'N RI.1HS1.(1H.\Xl Cement Corporation of India, New Delhi

SHRI O. S. SRIVA~TAVA ( Altemat« )Dn R. K. BH.,NO.\RI Central Building Research Institute (CSIR),

RoerkeeSUIU CIl.-\NOR.\ PH.\" A8H ( AII"nal, )

SUBI MAJIADln IhuAR.\HJA Ferro-Concrete Consuhants Pvt Ltd, IndoreSHRJ ,,\8J10K B.Il.\S.'HIA ( .4It"nat, )

58n, A. K. CHATTER.lF:F. Gammon India Ltd, BombaySHRI A. C. Ro\" ( Alt"nal, )

CRIE.· Exol~"~)O:1\ Caleuun Port Trust, CalcuttaS"t" S. Gl'MA (Alttl'IIalt )

SUUI R. K. 0.-\8 Gl-PT.' Simplex Concrete Piles (I) Pvt Lid. CalcuttaSHRt H. G\TJlA BI8\\· AS ( Altlrnatt ) ,

SHRI 1\. G. D.o\llTIU.\u In personal capacit)· ( 5 HUft,'rfottJ Cou", 121 HUft",.ford Str,II, CaMilla)

SRIII V. C. D:£~HPANJ",JI: Pressure Piling Co (I) Pvt Lid, IomlJayDIllEr-TOil Central Soil & ~fateriaJs 'Researcb Station,

Ne\v DelhiDP:Pt-T'· I) ntrCTOR ( AI"'IIt", ) ,

SHin A. H. Dl\P ..\N,'1 Asia Feundarion« and Construction Private Limited,Bomba~'

( Conli,.,,,d on/HI" 2 )

<e L'op,1ri,AI 1985BUREAU OF INDIAN STANDARDS

Thia publicatioD il preteeted under the /"dill" en"),,.,h' At' (XIV of 1957) andreprocluctioD In whole or in pan by any mean, e~t'ept with writteD penni.ion of tb.publish.....11 be deemed to be an infrinlemenl of coPyrilht uDd.r the said Act.

rl. 2111 ( Part 4 ) • 1115

(C,,.,i,..,1d fr.m /M" I )

Central \Varehousin. Corporation, New Delhi~{cKen&ieaLtd, BombayIn perlonal capacity (E·J04 A, Siml. H.uII,' JYt/JI""

SillRMd, B.mH~ )tnaineer. India Limited, New Delhi

Indian Institute oCTf'chnolo,y, BombayPublic \Vorks Department, Chandiprh Administra­

tion, Chandi,arhM, N, Dastur It Company PvtLtd, CalcuttaSKill S, R. KULK.~R"I

SKaI S. Roy ( AII,rntll, )811al A. P. MA.THUR.S••I V. B. l\fATlluaSKRIS.~UKHBRJEB

AIIfftWI R,/W,s,,,"'"SRal A. OBOIJlAL Stup COllluhantl Limited, BombayDRGoPAL a...IAN University of Roorkee, RoorleeeSs., N. JAGAN.A.TH Steel Authority of India Ltd, Dur,apur

SUI A. K.. MITB' ( .ill",..t,)SaRI ASHO~ K. JAil' G. S. JAIY It Auociatel, New Delhi

SKRt VIJAY KUMAR JAIS ( All""." )JOIl(T DIRECfOR ( DalOK ) National Duildin'l Orlanization, New Delhi

SJJBI SUJfJL B.-a" ( .AlmlUlll)JOINT DIRZCTOR RUEARCU ~finistr)' of Railwa)·s ( RDSa )

(GE )-1JOllfT DIRecTOR RJl:fSICARCH

( BitS ) ( Alt""." )Oa R. K. KAT'llSBRI J. S. KOIILI

S••I T .. K. D. MU:-fsiSHRI M. IYEJ(oAR ( .fll,,"at, )

S.RI A. V. S. Ro. MeaTY Indian Geotechnical Society, New DelhiS••I B. K. PA1fTRAXY Hindustan Conl'ruction Co Ltd. Bombay

SRal V. M. MADGE ( A/I,rnal, )SBJU M. R.. PUtfJA Cemindia Company Ltd, Bombay

SKftl D. J. KXTKAB ( Alt,rnat, )SaRI N. E. V. RAOHAVA~ Braithwaite Burn It Jeuop Construction Company

Ltd, CalcuttaDa V. V. S. R.,o ~.IadiConsultants Private Limited, New DelhiDa A. SAROUMAK College of Enlineeriol. Madras

SaRI S. BOJOllkATHA~ ( AlI,rnal, )SRRI N. SIYAOt1RU l\tlinistry of Shipping" Traruport ( Roads Win, )

SHat M. K. M17KKERJEIC ( Altnnat. )SO.BRJJfTDDING t N 0 I If E E n Central Public Worka Department, N.w D~lhi

( DEIIONS)ExsCVTIY& £ If 0 I ~ E • a

( DalolC. ) V ( Alt,rn.', )Da A. VA.ADA.AIA. Indian IDScitute oCTechnololY, New Delhi

D. It. KAXIA"" ( .4"""." )SOl Q. RA•••, Director General, JSI ( E.-offitY M",,", )

Director ( Cly En•• )

Sm".,,,SHRI K. M. MATHea

Joint Director ( Civ Ens. ). lSI

(eM';"'" • ,." II·)

2

AMENDl\1EN'I' NO. 1 MAY 19891'0

IS : 2911 (Part 4 ) - 1985 CODE OF PRACTICEli()I{ DESIGN AND CONSrrl{UCTJON OF

I'ILE }4~OUNDArI'IONS

PART 4 LOAD TEST ON PILES

( l:trsl Re vision )"

( Page 9, clause 6.1.6.1 ) - Substitute the following for the existingclause:

'6.1.6.1 However, routine lest shall he curried' for n test loud of utleast equal to the working load; the maximum settlement of the lest loadingin position being not exceeding 25 rnm.'

( 1)1)(' 43 )

R~progn\phy Unit.'BIS,NewDelhi" India

AMENDMENT NO. 2 JUNE 2010 TO

IS 2911 (PART 4) : 1985 CODE OF PRACTICE FOR DESIGN AND CONSTRUCTION OF

PILE FOUNDATIONS

PART 4 LOAD TEST ON PILES

( First Revision )

(Page 6, clause 4.2, second line) ― Substitute ‘0.5’ for ‘one-half’. (CED 43)

Reprography Unit, BIS, New Delhi, India

III 2111 ( P.... ~ ) -1115

Indian StandardCODE OF PRACTICE FOR

DESIGN AND CONSTRUCTION OFPILE FOUNDATIONS

PART 4 LOAD TEST ON PILEI

( First Revision)

o. FORE WO RD

e.1 This Indian Standard (Part 4) (First Revision) was adoptedby the Indian Standards Institution on 20 I·'ebruary 1985, after the draftfinalized by the Foundation Engineering Sectional Committee had beenapproved by the Civil Engineering Division Council.

0.2 Piles find application in foundation to transfer loads from a structureto competent subsurface strata having adequate load bearing capacity.The load transfer mechanism from a pile to the surrounding ground iscomplicated and could not yet be fully ascertained, although applicationof piled foundations is in practice over many decades. Broadly, pilestransfer axial loads either substantially by skin friction along its shaftor substantially by the end bearing. Piles are used where either of theabove load transfer mechanism is possible depending upon the subsoilstratification at a particular site. Construction of pile foundations requirea careful choice of piling system depending upon the subsoil conditions.the load characteristics of a structure and the limitations (f total settle­ment, differential settlement and any other special requirement of aproject. The installation of piles demands careful control on positlon,alignment, depth and involve specialized skill and experience.

0.3 Pile load test is the most direct method for determining the safeloads on piles including its structural capacity with respect to soil inwhich it is installed. It is considered more reliable on account of itIbeing ira-situ test than the capacities computed by other methods, such asstatic formula, dynamic formulae and penetration teat data. There arewidely varying practices followed for load tests on piles. Particularly,the difficulties regarding the establishment of an acceptable criterion, fordetermining the ultimate and safe bearing capacity of piles, and predie­ing the pile group behaviour from the test data obtained from individualload test on single pilei. cannot be under-estimated as the factors

IS I 2911 (Part 4 ) • 1985

affecting are filany. However, an attempt i. made to bring out an unifiedapproach to the various aspect of load test on piles. This standard wufirst prepared in 1979. The revised version has been prepared so as togive more details in regard to the rate of loading and unloading and thedetails of the situations when the different types ortests are conducted.

0.4 For the purpose of deciding whether a particular requirement orthis standard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off inaccordance with IS : 2-1960·. The number ofsignificant places retainedin the rounded off value should be the same as that of the specified valuein this standard.

1. SCOPE

1.1 This standard ( Part 4 ) covers the load test on all types of piles cove­red in IS : 2911 ( Part I/Sec 1 ).1979t, IS : 2911 ( Part l/Sec 2 )-1979:.IS : 2911 ( Part l/Sec 3 )-1979§, IS : 2911 ( Part I/Sec 4 )-198411, IS : 2911( Part 2 )-1980' and IS : 2911 ( Part :3 ) 1980·· and provides guidelinesfor determinati-m of safe load based on the following types of loadings.

a) Vertical load test ( compression ),b) Lateral load test, andc) Pull-out test.

1.2 Load tests under vibratory loads, moments and other forces andsequence of loading under special circumstances like yield load capacityof buckling piles are not covered in this standard.

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shan apply.

2.1 Cat-OS- Level - The level where the installed pile is cut-off tosupport the pile caps or beams or any other structural components atthat level.

-Rules for roundiftl off numerical value. ( r,uis,~ ).tCode of practice for design and construction or pile foundations: Part 1 Concrete

pilei, Section 1 Driven calt i"-sil,, concrete piles (first "Dis;'" ).tCode of practice for design and con.4Jtruction of pile foundationa: Part 1 Concrete

piles, Section 2 Bored cast ira·situ concrete piles (firs' ,lVisiota ).§Code of practice for detign and construction of pile foundations: Part I Concrete

pile!', Section S Driven precast concrete pilei (ps' rlvisio,. ).IICode of practice for design and construrtion of pile foundations: Part 1 Concrete

pilei, Section 4 Bored ~reca.t conerete pilei.,Code of practice Cord.isn and construction of pile (ouadatiQDJ: Part 2 Timber

pUes (first rms;o1l ).*'Code of practice for design and construction of pile foundations: Part 9 Under­

reamed piles (first ""';SI01l ).

4

IS I 2911 ( Part 4 ) • 1985

2.2 Dat... Bar - A rigid bar placed on immovable supports.

2.3 Pactor 01 Safety - The ratio of the ultimate load capacity of apile to the safe load of a pile.

2.~ laitial Te.t :- It is carried with a view to determine ultimate loadcapacity and the safe load capacity.

2.5 Keatleclle - Dead-weight used for applying a test load on piles.

2.6 Net DI.plaeemeDt - Net movement of the pile top from theoriginal position after the pile has been subjected to a test load andsubsequently released.

2.7 Roati.e Teat - It is carried out on a working pile with a view tocheck whether pile is capable of taking the working load assigned to it.

2.8 Te.t Pile - A pile which is meant for initial test.

2.9 Total DlaplaeemeDt ( Gross) - The total movement of the piletop under a given load.

2.10 Total Ela.tic Dl8placemeat - "fhis is magnitude of thedisplacement of the pile due to rebound caused at the top after removalof a given test load. This comprises two components as follows:

a) Elastic displacement of the soil participating in load transfer,and

b) Elastic displacement of the pile shaft.

2.11 Ultimate Load Capacity - The maximum load which a pile orpile shaft can carry before failure of ground ( when the loil fails by shearas evidenced from the load settlement curves) or failure of pile.

2.12 Sale Load - It is a load on a pile derived by applying a factor oflafety on ultimate load capacity of pile as determined by load test.

2.13 WorklDI Load - The load assigned to a pile according to design.

2.1f WorklDI Pile - A pile forming part of foundation of a structuralsystem which may be used for routine load test. #

3. NECESSARY INFORMATION

3.1 The following information is necessary for pile(s) on which test ispropoled:

a) Pile type including material and reinforcement details, group ofpilei, if any;

b) Method of driving with driving record or installation;c) Pile depth(s) and details of crols-section(s);

5

III 2111 ( Part ~ ) • 1_

d) Type of telt desired;e) Layout of the pUe(l) - 'pace ayailable around and position in

the group for lingle pile test;f) Depth of water table and soil strata details with soil telt relultl;~) Safe load and ultimate load capacity, and the metbod(l) on

which based;11) Availability and provision of type of piles or anchors or kentledge

for reaction;j) Nature of loading/loading plan with a particularly mention of

pile(l) which may be free Itanding when .cour i. expected; andk) Any other information concerning planning and conducting the

tests including the relevant palt experience concerning similartest{I).

4. TYPES OF TESTS

4.0 There are two types of tests for each type of loading (that ii, vertical,lateral and pullout ), namely, initial and routine test.

4.1 laltlal T••t - This test is required for one or more of thefollo\\'ing purposes. This is done in case of important and/or majorprojects and number of tests may be one or more depending upon thenumber of piles required.

Non: - In cale specific information about strata aDd put luidiul experi~Dce isDot available, there mould be • minimum of two testl.

a) Determination of ultimate load capacities and arrival at safeload by application of factor of safety,

b) To provide guidelines for setting up the limits of acceptance forrou tine telts,

c) To study the effect of piling on adjacent existing structures andtake decision for the suitability of type of piles to be used,

d) To get an idea of suitability of piling system, ande) To have a check on calculated load by dynamic or static

approaches.

4.2 R.ad.. Te.t - This test is required for ODe or more or thefollowinlr purposes. The Dumber of teatl may generally be one-halfpercent of the total number of piles required. The number of the teatmay be increased up to 2 percent in a particular cue depmdin, uponnature, type of structure and Itrata condition:

a) One or the criteria to determine the saCe load of the pile;b) Checkmg saf. load and extent of ..rety (or the specific functional

requirement of the pile at workiDlloadj and6

IS I 2111 ( ....t 4 ) • 1115

c) Detection oC any unusual performance contrary to the findingsof the initial telt, if carried out.

5. GENBRAL REQ,UlREMENTS APPLICABLE TO ALL TYPEIOF TUTI

5.1 Pile telt may be carried out on a ~ingJe pile or a group of pilei asrequired. In case pf piJe groups, caps wiU be provided such that therequired condition. ,r actual use are fulfilled.

5.2 Generally the load application and deflection observation will bemade at the pile top.

U In particular cases where upper part of pile is likely to be exposedlater on due to scour, dredging or otherwise then capacity contributedby that portion of the piJe during load test shall be duly accounted for.The pile group' in tbe.. conditions shall be tested without tlleir capresting on the ground.

5.4 The test should be carried out at cut-off level wherever practicable,otherwise suitable allowance Ihall be made in the interpretation of thetelt results/test load if the test is not carried out at cut-off level.

I. VERTICAL LOA.D TEST (COMPRESSION)

1.1 0 .....1 - In this type of test. compression load is applied to thepile top by mealll of a hydraulic jack against rolled steel joist or suitableload frame capable of providing reaction and the settJement is recordedby suitably pOlltioned dial gauges. Maintained load method as givenin 6.2 should be used for determination of safe load, Howev er, forspecific requirements cyclic and CRP methods, which are alternatemethods, may be used as mentioned in 6.3 and fi.4. The general require­mentl applicable for these three methods are given frolb 6.1.1 to 6.1.6,unlel. otherwise specified.

'.1.1 p"p4,IJJi,n ofPil, IlIad - The pile bead should be chipped offto natural horizontal plane till sound concrete i. met. ~ The projectingrejnforcement should be cut off or bent suitably and the top finished.mooth and level Yvith plaster of Pari. or similar synthetic material whererequired. A bearing plate with a hole at the centre should be placed onthe head of the pile for the jacks to rest.

1.1.2 A./JllictJt;on of lAad - (Not applicable to CRP method.) Thetelt should be carried out by appJyil1" a series of vertical downwardincremental load each increment beinR' of about 20 percent of safe loadan the pile. For teltin. of raker piles it is elsential that loading is alongtbe axil.

7

18 I 2911 ( Part .. ) • 1985

&.1.3 Rlaction - The reaction may be obtained from the following:

a) Kentledge placed on a platform supported clear of the test pile.In case of load test below under-pinned structure, the existingstructure if havin, adequate weight an,d suitable, conltruetionmay serve as kentledge. The centre of gravity of the kentledgeshould generally be on the axis of the pile and the load appliedby the jack should also be coaxial with this pile.

b) Anchor piles with centre-to-centre distance with the test pile notless than 3 times the test pile shaft diameter subject to minimumof 2 m, If the anchor piles are permanent working pilei, itshould be ensured that their residual uplift is within limits. Careshould be exercised to ensure that the datum bar supports arenot affected by heaving up of the soil.

c) Rock anchors with distance from the nearest edge of the piles atrock level being 2 times the test pile shaft diameter or 1-5 mwhichever is greater.

6.1.3.1 The reaction to be made available for the test should be25 percent more than the final test load proposed to be applied.

6.1.4 Settlement - ( Not Applicable for CRP Test. ) Settlement shall berecorded with minimum 2 dial gauges for single pile and 4 dial gauges of0·01 mm sensitivity for groups, each positioned at equal distance aroundthe piles and normally held by datum bars resting on immovable supportsat a distance of 3 D ( subject to minimum of 1·5 m) from the edge ofthe piles, where D is the pile stem diameter of circular piles or diameterof the circumscribing circle in the case of square or non-circular piles.

6.1.5 The safe load on single pile for the initial telt should be least ofthe following:

a) Two-thirds of the final load at which the total displacementattains a value of 12 mm unless otherwise required in a givencase on the basis of nature and type of structure in which case,the safe load should be corresponding to the stated total displace­ment permissible.

b) 50 percent of the final load at which the total displacementequal 10 percent of the pile diameter in case of uniform diameterpiles and 7·5 percent of bulb diameter in case of under-reamedpiles.

6.1.5.1 However routine test shall be carried for a test load of at leastone and half times the working load; the maximum settlement of testloading in position being not exceeding 12 mm,

8

IS I 2911 ( Part 4 ) • 1985

&.1.6 The safe load on groups of piles for initial test shall be least of.the following:

a) Final load at which the total displacement attains a value of25 mm unless otherwise required in a given case on the basis ofnature and type of structure, and

b) Two-thirds of the final load at which the total displacementattains a value of 40 mm.

6.1.6.1 However routine test shall be carried as in 6.1.5.1 themaximum settlement not exceeding 25 mm,

6.2 Mailltai.ec1 Load Metlaod - This is applicable for both initialand routine test. In this method application of increment of test loadand taking of measurement Or displacement in each stage of loading ismaintained till rate of displacement of the pile top is either 0·1 mm infirst 30 minutes or 0·2 mm in first one hour or till 2 h whichever occurfirst. If the limit of permissible displacement as given in 6.1.5 or 6.1.6fs not exceeded, testing of pile is not required to be continued further.The test load shall be maintained for 24 h.

6.3 Cyclic Method - This method is used in case of initial test to findout separately skin friction and point bearing load on single pilesof uniform diameter. The procedure as given in Appendix A or byinstrumentation may be used.

6.4 CRP Method - This method which is used for initial test isgenerally considered to be more suitable for determining ultimate bear­ing capacity than the maintained load test but the load/deflectioncharacteristics are quite different from those of the maintained load testand cannot be used to predict settlement of the pile under working loadconditions, This method should not be included in routine test. Theprocedure is given in Appendix B.

7. LATERAL LOAD TEST ON PILES

7.1 The test may be carried out by introducing a hydraulic jack withgauge between two piles or pile groups under test Or the reaction maybe suitably obtained otherwise. If it is conducted by jack located bet­ween two piles or groups, the full load imposed by the jack shall betaken as the lateral resistance of each pile or group. The loading shouldbe applied in increments of about 20 percent of the estimated safeload.

7.2 The next increment should be applied after the rate of displacementis nearer to 0·1 rom per 30 minutes.

7.3 Displacements shall be read by using at least two dial gauges of0·01 mm sensitivity (s" Fig. 1 ) spaced at 30 em and kept horizontally

9

II. 2111 ( J-Ui 4 ) .1115

_ above the other Oil the telt pile and the di'j)lacement iaterpolated ateut-ofr level from limilar t~11awhere cut-oft' level Ja unapproachableand for approachable C1&t-otr level, bowever, ODe dial .au.e placeddiametrically opposite to the jack .hall dinctly meuure the displacement.When, it il not pouibJe to locale Mi. of the dial .au... in the Ii•• ofthe jack axe., then two dial ,aulI. may be kept at a dilt.nce or so emat a luitabJe heilht and the djtpJacement interpoJated at load poiDt fromsimilar triangles.

Non - ODe of the method. (or ..... tliaJpup aD pile IUdlce is to chip ofFUD-vea CODer•• on the lid. or the .. aad to fix • pleie of ,I•• 20 to SO •• Ielare.Th. dial pu,. tip. aball rese OR alae _tral portioD 01the ,lui plate.

oJACK

DATUM BAASUPPORT SUPPORT

FlO. 1 POIn10K tW DA..". BAa SupPOan

7.f The ••re lateral load •• the pile ahall he take" a. the Jealt of therollowing:

a) Fifty percent of the laal loael at which the total dilplacemeatincrea.es to 12 mID;

b) Final load at which the cetal cliIpJaceJDIDt c-.orre.pond. to ~ mm;and

c) Load corre.pondja, to aD)' other .pecJSed di.pJacement .. perperformuce Nquire_.

NOft - Tbe di.plac••• II at tIM c.-oWl.... ol .. pile.

10

18 • 2111 ( Pal't .. ) • Itl5

7.5 Pile groups shall be telted under CODditioDI al per actual use in thestructure as far a. poaaible.

L PULL-OUT TEIT ON TD PILa

1.1 Uplift force may preferably be applied by means of hydraulic jack(s)with gauge uling a suitable pullout let up.

NOTB - One of the method. for pull out t.e. that may be used is where hydraulicjack is m..de to rest on rolled 11..1 joi_(a) ..tin, on two Iupportl on the greued.·"'bc jack r(lacts 81ainac a Crame attacllecl to tlte top of the te.t pUe such that whentbe jack is operated, the pile letl pulled up and tbe reaction is tranJerred to tbeRround through the supports which ar. at J.st 2·5 D away from the teat pileperiph.ry (,vhere D i. pile .t~m diameter of circular pilei or diameter of thecircumscribing circle i. the ca.. 01lCl-re piles). The Cramework can be attached10 the pilt- top ,vitb the reillforcement ban which IDay b. threaded or to whichthreaded bolts may be welded. AI an altetaative if it sometimes preferable to uaea central rod (Iesi,ned to tAke pile load aDd embedded centrally in tbe pile to alenltb equal to the bond lentlh load required. It will have thread. at top for fixi...it co the framc\\'ork. For I.fler load. the number of rods ma y have to be more anddependil1l on the set-up the.. Inay be put in a lift. or ill any other .ymmetricalpattern. For routine tests, the ftam.work i. normally attached to tbe reiaforciulhart but n ('entral rod may also be used in case the upper portion of the pile isrequired to be hl,ill up.

8.2 The test pile shall have adequate Iteel to withstand pulling. Insome cases, in order to allow for neck tension in a pull out test, it lnay benecessary to provide additional reinforcement in the piles to be tested.

8.3 The pull out load increments and consequent displacement readingsshall be read as in the case of vertical load test.

8.4 The safe load shall be taken as the lealt of the following:

a) Two.. third. of the load at which the total displacement is 12 mmor the load corresponding to a specified permissible uplift, and

b) Half of the load at which the load-displacement curve shows aclear break ( downward trend ).

1.5 The initial test shall be carried out up to twice the estimated safeload or until the load displacement curve shows a cleat- break (down­ward trend ).

I.' R.outine test shall be carried out to one-end-a-half times the estimatedlafe I03d or 12 mm total displacement whichever is earlier.

t. UCOIlDING OF DATA AND PUlBNTATION

t.1 The pile telt data •••nti.Uy conce..... th .... variables, namely, load,displacement and time. TIM..... to be 'recorded sequeatially for thet_ under coftlideration ••41 recorded in a auit.ble tabular form alonlwitb tbe information about the pile.

11

III 2911 ( Part 4 ) • 1985

9.2 The data may be suitably presented by curves drawn between thevariables and safe loads shown on the graphs. Load displacement curveshould be an essential part of presentation.

APPENDIX A~ Clause 6.3 )

CYCLIC LOAD TEST METHOD

A-I. METHOD

A-I.I Alternate loading and unloading shall be carried out at each stageas in 6.1.2 and each loading stage shall be maintained as in 6.2 and eachunloading stage shall be maintained for at least 15 minutes and the sub­sequent elastic rebound in the pile should be measured accurately bydial gauges as in 6.I.t. The test may be continued up to 50 percentover the safe load.

A-2. ANALYSIS OF RESULTS FOR FRICTIONAL RESISTANCE

A-2.1 Graphical Method

A-2.1.1 The analysis shall be done as explained in Fig. 2.

.\.-2.1.2 Assuming that there is no compression in the pile, plot a graphrelating total elastic recovery and load at the pile top.

A-2.1.3 Draw a straight line paraJJel to the strajght portion of curveI to divide the load into two parts and thereby obtained approximatevalues of point resistance and akin friction.

A-2.1.4 From the approximate value of skin friction J and knowing theloads on top of pile, compute the elastic compression of the pile corres­ponding to these loads, by the following formula:

~ _ (T- F/2)LAE

where

6 - elastic compreuion of pile in em,T .. load on pile t6p in kif,F == frictional reaiatance in kIf,L - leDllh or the pile iDem,.4 .. crol.·..ctional area or the pUein eml , andE - modulul of elasticity of the pile material in klf/eml.

12

IS I 2111 ( P.~a 4 ) • 1185

LOAD ON PILE TOP IN TONNES

0-5

E '·0E~LIJ0 '·5 SKII~ FRICTIONc:(Q:0•en:J 2-0(/)

u, PARALLEL0 ,? 2-5 \ II0 \U; POINT

\(/) \ III AND FINALlJJ RESISTANCE

\exQ. 3-0 \~ \0 \ \u r-PARALl El --,~ 3-5t- \ \(/')4 \ \...J \ \UJ 1.-0 \ \1\

\ \

\ \

'·5 \ \,\ \\\

,,Flo. 2 ANALYSIS OF CYCLIC LOAD TEST DATA POR SEPARATJO~OF

SKIN FRICTION AND POINT RESISTANCE

13

III 2111 ( Part 4 ) ~ 1_

(The value should DormaUy b, measured from an expoled portiODof pJle Item by means of compreuometer durin, the load telt itae1f. )

A-2.1.5 Obtain valu. or the elutic compreaioD of the lubgrade bylubtractiDI the elastic compreuioa of the pUe from the total eJaltlcrecovery of pile, and plot the graph reI.tiDS theae Dew valu. to thecorresponding load. on pile top. WheD elutie compreN.ion of the sub­Irade works out negative, the Delative value Ihall be ignored until tbevalue is positive.

A-2.1.& Repeat the procedUftl given in .-2.1.3 to obtain new valuesof skin friction. .

A.-2.1.7 The proCell of further approximations covered in A-2.1.1 maybe repeated further to any d.ired extent, but usually the third curvewould give sufficiently accurate values for akin friction for practicalpurposes.

A-2.2 Aaal)'tleal Metk_

A-2.2.1 From straight line portion of curve ( HI Fig. 2 ) calculate thevalue of constant from the equation ( 1 ).

rn ~ tl.. - ( ~E-)L ..... , ., ( 1 )~~

wherem a= a constant;

6.. .. change in total elastic settlement of pile top = ( S - S ),in em;

~T .. change in applied load all ( T b - T a ) in kgfjL = length of pile iD em;A - cross-sectional area of pile in em l ;

E -= elastic modulus of the material of the pile in kgf/eml;and

T =- load on pile top in kIf:

A-2.2.2 Calculate the corrected lettlement for different load incrementby equation ( 2 ).

S = ",T .•....... ( 2 )

where

S =:II corrected settlement in em, andT -.:; total load on pile top in kgf.

14

II I 2111 ( Part 4 ) - 1_

A-U.S Knowing value of WI and S compute akin friction and pointbearing by solving simultaneous equation ( 3 ) and ( 4 ).

T --: P + F ( 3 )( T - Ff2 ) L '

S .. mP + - AE _.. - -_. ( 4 )

where

P - point bearing in kgf, andF skin friction· in kgf.

APPENDIX B( Cltlus, 6.4 )

CaP TBn

B-1. PROCEDUIlE

8-1.1 The load shall he measured by means of pressure Qf 0·01 mmsensitivity load gauge. The penetration ( deflection ) should be measuredby means of dial gauges held by a datum bar resting on immovable supportsat a distance of at least 3 D ( subject to a minimum of 1-5 m) away fromthe rest pile edge where D is defined in 6.1.5_ One of the dial gaugeswill be selected fot conducting the telt. With continuous apphcation ofpressure on tlte pile top by operating of the jack, a person watches therate of settlement of the dial gauge against a stop watch held in his handand directs the pump operator to pump faster or slower or at the samerate as needed to maintain the prescribed rate of settlement say at every0-25 mm settlement, he gives an indication to take readings. Immedia­tely, other persons record the pressure gauge readings and other dialgause readings. The pump supplying the jack may be hand ormechanically operated. For force up to 200 ton hand pumping is con­venient. If a mechanical pump i. used, it should, for preference, havean 'infinite variable' delivery, controlled either by a bitted valve or avariable speed drive.

11-1.2 The jack should be operated to cau.. the pile to penetrate atuniform rate which may be controlled ~r cbeekinl the time taken forsman increments or pmetratiOb ad acIjultial the pumpin. rate accord­iDlly_ Reading. of time, penetratioa ud load Ihould be taken atlufticiently clole interval. to lift ~ua&e coacrol of the rate of penetra­bon. A tate of penetration or abeut 0'15 81. per minute i••uitable forpredominantly friction pUlL P., ...........t11 end••rinl pile. inIUld o~ Iravel, rate or peaetrati_ o( I-S•• per minute may be uled.

15

III 2911 ( Part t ) • 1"5

·fho rata of penetration, jf steady, may be half or twice these valueswithout significantly affecting the results, The test should be carriedGut for the penetration more than 10 percent of the diameter of thepile bue.

11-1.3 As the test proceeds a curve between load and penetration shouldbe drawn to determine when the ultimate load capacity has beenreached.

B-2. ULTIMATE LOAD CAPACITY

114.1 The curve of load versus penetration in the case of a predominantlyfriction pile will represent either a peak and the subsequent downwardtrend, or a peak and then almost a straight line, as shown in Fig. SA.The peak load marked .A in Fig. 3A will represent the ultimate loadcapacity of pile.

11-2.2 In the case of predominantly end-bearing pile the curve will besimilar to that shown in Fig. 3D and the ultimate load capacity may betaken u the load corresponding to the penetration equal to 10 percentof the diameter of the pile base.

5

f..0'co,.j

100

80

60

20

a

A

I~~ lA~

/1V

1/J,

10 15 20 2SPENETRATION, mm

3A Predominlntlv Friction Piles

16

30 35

~---------~~

~r

/III

II,

200

160

t 120

Q'a 80-J

40

o 12-S 2S-0 37·5 50-0 62-5 15·0PENETRATION. mm

38 Predominantlv End Bearing Pilei

Flo. 3 LOAD VS PENETRA1JON CURVE IN CRP TEST

17

III Bil ( Pa..et ) • It15

(c••n••~ fttnll ,.,, 2 )

Pile Foundations Subcommittee, BDC 4S : 5e...,

SIIRI M. D. TAXR•• A.ftPradeep Villa. 92 Kotnis Path M:ahim, Bombay

AI".", R"r's.,i",SHRI CK.''''JI&A PRAKAIJII Central Duildins Research Institute ( CSIR ),

RoorkeeSURl K. G. 0.\.0 ( All""." )

S.al A. aRMHAL Stup Conaultantl Limited, BombayS••I ft.1. IYDOAB Enlin..r. India Limited, New DeIhl

SJIRI J. K. DAGeUI ( AI,,,,,.,, )SURI P. K. JAI. Univenity o'Roorlce~,RoorkeeSIIRI A. N. J.xaL. J\lia Foundations and Construction Private Limlt.d,

BombavJOI"T DII"WCToa R,....A.~J( ~tinistry o'"Railways ( RDSO )

( GR )-11n.PC" DIR.croa a••ABell

( GB )-111 ( AI,,,,..,,)SKRt D. K. PAnHAIt\" Hindustan Construction Company Limited, Bomh3Y

5H"1 P. V. HAIX ( AI",.,,)5••, M. Il. PV."A Cemlndia Company Limited, Bombay

5."1 D. J. Kft1C.'. ( A"""'" )S.al 8. RuftO.,. Pilc Foundations Construction Company (India)

Prlyate Limited, CalcuttaSR.l s,C. loR. ( ..""""" )

SU••RIYI'DDIKO E y a I ~ E E R Crntral Public \\forks Department, Ne\¥ Delbi( D_IONI)

ES"t-'I'n·J: E If 0 , " Ii: • R( DElIa". ) V ( ..1"',,..,, )

18

BUREAU Of INDIAN STANDARDS

HHdqIMtffInI:MM. Shav.", 9 Bah.tur Shah latar~. NEW DELHI 110002T.lephon••: 323 0131, 323 3375. 3231«»2 Fax:+ 81 011 3234082. 3239398, 3238382E· ...... : bla@vanl.com. W.ba... : http://www.bla.org.1n

550 1348

8394955

3237817

3378882

803843

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83282 85

52-&1 71

21451

212808

421.51

3782 51

403827

218835

8428261

471 1888

Sinha Path. 54 11 37

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Northem : sea 335-338, Sector 34-A, CHANDIGARH 160022

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twestem :~., ES. MIDC, Behind MaroITelephone Exchange.Andherl (Eat), MUMBAI400083

SNItCh 0""..:'Pwhpak', Nurmohamed Shaikh Marg, Khanpur, AHMEDABAD 380001

Peenya Industrial Atea, 1.t Stage, Bangalor.T...,kur Ro.t,BANGALORE 580058

Convnerci"-eum-otflce Complex. Opp. Duaher. Maldan, E-5 Arer. Colony, 72 34 52Bib" MMcet. BHOPAL 482018

62183. Ganga Nagar, UnitVI, BHUBANESWAR 751001

5th Floor. Koval Towers, 44 Saia Sund.am RoIKi. COIMBATORE 841018

Plot No. 58. NeeI.m Sala Road, NIT. FARIDABAD 121001

Savltrl Complex, 118 G.T. Road, GHAZIABAD 201001

53/5 Ward No.28, R.G. a.u. Road, 5th By...,.., ApurbaGUWAHAT1781003

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Seth Bhawan. 2nd Floor, BehInd Lee" a.-rna, Nw" 1<1_01'. Ao-.d, 21 88 23LUCKNOW 221001

NIT Building, Seaond Floor. GokuIpat ...... NAGPUR 4«)010,.....Ir Shaw.., tat floor. Rap_ Raid, NALAGARH 174101

Patliputra Induetrllll eatatll, PATNA 100013

FIrst Floor, Plot Noe. 887-880,~ YMI, ctutt.tccl, PUNE 41 1037

s...,.,.nd ......' 3nI Floor.....7 p'ade.ID,... ......AAJKOT 3IODQI

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