this document downloaded from vulcanhammer.info the website about Vulcan Iron Works Inc. and the pile driving equipment it manufactured
Visit our companion site http://www.vulcanhammer.org Terms and Conditions of Use: All of the information, data and computer software (“information”) presented on this web site is for general information only. While every effort will be made to insure its accuracy, this information should not be used or relied on for any specific application without independent, competent professional examination and verification of its accuracy, suit- ability and applicability by a licensed professional. Anyone making use of this information does so at his or her own risk and assumes any and all liability resulting from such use. The entire risk as to quality or usability of the information contained within is with the reader. In no event will this web page or webmaster be held liable, nor does this web page or its webmaster provide insurance against liability, for any damages including lost profits, lost savings or any other incidental or consequential damages arising from the use or inability to use the information contained within.
This site is not an official site of Prentice-Hall, Pile Buck, or Vulcan Foundation Equipment. All references to sources of software, equipment, parts, service or repairs do not constitute an endorsement. '
Application of the wavc equation analysis to friction piles in. sand
, F. A. TAVFNAS ~~l~/~l1I'lt1l~~tll(!/ (-ii.il F.'l~,ci~r~~~ri~rg, I,(l\~iiC!~ti\,c~rs;ry, Q111,bcc City, QIIC.., Con(,(io
AX11 J. bj. E. AL~~)~I~EKT (;(,,l:c( ir~rir(/I I.~~,yi/rl~r.r.\ /ti(.. . .i.?JO Crossr~ici~.Dr.. I(crr~.cron,T,Y. 1J.S.A. 77063
1:cceived June 23. 1976 , Acccptcd Scptcn~her7. 1976
I{a~.cilon tkc inft~r:ii.ific~ngalhereel clurii~ga c!c\ign pilc testing pr-~Jgramand the st~hccqttrnt it~tI I I I f111:1t In ()!~cbei ('it!. the pc~teritiiiland limitation of the nave t~qt;.t!iot?ri?ct!iocI :II!;II)51ng pil~ t111ving llch;f\ ~OLII-:~i.c cler~lo~st~~[cd. 'I'll~:li)lllic;~tion of tlic \\ti~~ctlcr,~iion ri~cthtrcl to in\tti!mciitcd precat concrete pile, Jri~en 11ncl~r:~c!! i.ori!t~*l;ccl ~~c~iiclititriir Ic,lcli to csccl' .lit pl.c~iictionsboth irl rcrmb of drivir~gsfr-esses . . i111ei 01 111iini;i1cI>C:II~,-! L':l!l, (~C Introtluction reasons, the method is used only on a vcr! Follo\\lin!: thc stucly of pile tlri\.ing inipnct by lirnitcd scale in Canada. While the fundalncnt:~~ Smith ( 19501, tllc tlsc of tl~cl1.1cory of wavc aspccts of the wave equation rncthnd ll:~\c propagation for !tic ;~rialysisof pilc clriving has bccn the object of numerous papers, relativc.l! grariiially dcvclol~ed It) rcs~ilt in the forriial littlc data ha~ebccn published or1 the nllplic.;i- ~)ro~'osiiior~ol IIIC so-c.:!ilc~i \\.n\c cquation tion of this nlctllod to production piles so thal 1 s 1 1 iirr f tlic potqntial and ]inlitations of tllc \\-n\.e c~ltl:l- ] !!I it! I p;tion \\.l:cil applied to real field situatiotls ;ire. (Sr:iit!l I ')(it)1. l'\ii.~l.;i\.~:i.\t..~i ..I1 \\.as carricd not clearly cstablisl~cd.It is the purpose of lllc 0~:irl t!lc i?cric):l 01 19(1(.111: 1970 to dc\.clol) prcscnt study to provide sucl~information in 11111 I I :trticIs t tiI the C~SCof precast concrete piles driven ill 1t.ch11iquc.sfor nio~ic.li!l~tllc (11 i\.iiig sj.slcm. thc snnrl by mcans of free-fall hammers. pile. ;~iltlthc soil. Siilcc I OiO. lhc \vavc cclua- TIlc cnnstruct.ion of I\\Q 12 500 ft (3800 nl 1 1 llioiI I ti~IL tilong retaining \valls on bot]l sides of the Saint- in the 1i:iitcd Sti11c.; fc)r I?otli ori~l~o~cand ofl- Cllarlcs f . . . , -< Kg- ',>'", . +,:,:,;<,,:,:,+, 17ile foun;!ation in a sand deposit of medium analysis was :llso matlc as sum in^ tvnic:tI ~..limit. 1 : ,,:!;, , -~,~r?~;;~+~y$~;i4i+~i L7 i i density. The design of this foundatio~i was vnlucs of tlic ilij~utpar-ametcrs to estirnatc tile b;lsed on the results of an extensive pile ciri\.irig possible accuracy i?f 1)carirrg ~:\pncity~~redic- and test loading program, in which tlie vari:l- tions in caws \\.llt.rc ,110 ticinilcd st~rciyof sucll tions of the driving resistance and the static parariicters coultl bl: riiarle. bearing capacity \villi the depth of enibetinicr~t tllc !U 3. T;inally. tlic quitli~yof bearing capacity !.f in sand were determined for. fou~types of piles predictions for 30 pro~luction1)ilcs test I'onded and in particular for a 12 BP steel I-I-pile and to failure \\.as e\.:~lu;ltcd I,y comparing the for an H-800 Herkules precast concrete pilc. \\.:ive ecjuatior~rcs~ritc to rllc o1,scrvations made Details on the soil properties at the site, on the on ihc ~~sc~luitionpile.;. -1'Iiis cxc is tliouglit pile tcsting program and on the results obtained to rnorc i.cpi.csent:~ti\.c of stnnciartl ficlcl Ilave been presented by Tavcn:ls ( 1Y7 1 j. co:?tlitioiis \\licr.c driving cor~ditionsas wcll as Tlie hexagonal precast concrcte piles were, cluniity ct>ntrois~vcro less uriifor~m. finally sclectcd for the ioundation ancl tlicir length \vns specified in accordarice \vi!h tlic C'h:trnc.lcristics of the I'roject re~ult.sof the test program. In order to ensure C;P(I\CC/I~I;(YI/Cot1di1iot1.s [lie necessary quality of the production piles, Tlic' geotecllrlical corlditions prevailing on !he contract documents recluirecl the recording the Saint-(.'li:~rles Iiiver site ar-e very uniform. 116 the driving resistance on all piles as \~cilas They Il;r\,c bccn desc:ribcd in d~tailby 7'a\c1lns rlic te5t loading of 39 piles, selectecl at random ctl. ( 1') 70 ). .l'd~vcrias( 107 1 ), anil Ta\!cn;is hy tlie ungincer. As a rcsult, cstensivc infor~n:l- ;ilid /?ucly 1 1072 1. ,\ typical soil ~~rofilcis lion was gathered on the driving beli;l\,iour of s:iou.~i in I?$. I. .I'lic s:rncl layer \vliicli is tllc as \\.ell as on eventrrnl corrcl:ltiorls niaiii l'c:~turc (,I' this tlcposit llus hce11 p~.ovcrl en the len_rth of pilc, tile final tiri\,ins tinilorrii over t!;~c111ir.c 17r.c)jcct arc;I, ho:Ii in and the static bearing ,;~pncityof tcrriis of gr;ii!:iii<)~iant1 of density. 'r'ilc i~at~i~.al precast ccjncrete piles driven by free-fall ham- backlill shc~wnon Fig. 1 \vas cxcav;~tctl;>rinr nicr in niediurn dense snqd. T'licsc results Ivcre to piling ant1 \\,;I.; rcj>la(,cd lly ;I 1.5 ft (4.5 ni) u\ed to demonstrate the lirnitittions of iht usual tllick Ia!es cjf unconlp;tcrcd 0-4 in. (0-10 pilz driving formulas by Tavenas arid Autiy CIII j crlichcd stoiie. 7'iii~ur~if~)r-rliit>. of tile soil (1972). The same set of data can rio\v bc conclirions iisst nl:~tlc it pc)ssibIc to clesigri the uscd to investigate the cnpnbilities arid lirtiita- founclr~tic~nascrl.;~ing th,:\ tllc rcs\ilts o\,tiiir~cd tions of the \vave ecluation method of pilc clurir~gtlic tcht pio;r.ilm carr-icil oiit :it a ccrlti.al :1n3lysis. locntiori \\.cri' al~l~lrcableto j1ilt.s at ~triyloc;l- The invcstigntion reported herein has bee11 divided into three sections: slanaufd penelrotion I ndex . blow3 / loot I. Using the vbservations made on four production piles u.liich had been instrunicntcd boci,,: for stress measurement (Tavenas and Audy 1972), a brief parametric study \vas carricLl out to evaluate the influence of thc illput parameters on the dri\,ins strcsses and tht. bearing c:lp:lcity. Tlic. 'most rcprescnt:rtivc' \,:~lues \vere selected :IS tlior;c producing [hi. rnedw?. '-I 43 ht.51 fit b:tu:en observed and cc~rnl.uteil d:i\ irig ""'C'" stresses and bearing capacities. The valucs \\.ere then uscd in the renioiilclci- of the invcsti- cation. , . 2. The wave eq~rationnlethod \vas applied 70 to a steel I-I-pile and a 14erkules precast coil- slcvel --- crete pile driven and tested under ~vellcon- 8 0 .."-d conditions durin? thc design testins ),trn. In addition to the calibrated moilci I ,:[(,. 1. rkpi~~,~stjt~ p,.~,,i/c--y;li,l~- Herkulcs H-SO0 piIc in both gcolnctry ancl at inipacr. Experience proved the ' rcsul!s meclii~nic;l!proper-tic?. Thc pilcs, \\it11 icnglhs yielded by these f6rmulas to 'be very variable varying from 28 to 34 ft (S.5 to 13.4 m), in quality and numerous attempts were matlc TAVtNAS AND .4111)11It:RI' 3 7 p to establish 'improved' formulas of iiicrcnsing tion as npldicd to pile driviii~olfcrs a mealis complexity. However, all these attempts se- of obtaining n truly ~iiatlicniatical solution". ; 8 { :I,: ,%,;.pi?, rp.~.f~,.:Xc.~t,I.qj~~:~ ::+;;25$$+{<'* A:; ,.I mi rnained unsuccessful due to the failiire to Fiiialiy Smitli ( 1960) prcsc:itcd a cornprclicri- ;;;i! :;my> 4,,~t.:>;:;T<$j~!? ,I, 7 ',-,'.?,,< \,> ;>"o,,',M,>&, ,r.ecogni7.e the fallacy of the basic assuniption sive trcatnicrit of [lie apl~lic;~rionof tile wave ,, 1 $,,,::,+!. ,.7,\y:;*:i;:.+,!;$,!', . .r. ., >.I,::..A,+, of a Nelvtonian impact used in all cases. Isaacs equation riictliotl to tlic :~~i:rlj.sisor ~>ilcdl-ivinr. , , :.i,-d,~* f $,;..A,t... .) ,,., t;eiflc:~:m. . cr-<,,? **-7. , '- I,:,:l,f.,T :7 "L ::,:;j;~**\:/-: ( 1931 ) was the first to point out that the ~ilispaper, \\,liicli is still tiit, bas/c rcfel.cn& ,, :(), .:,3,~r,2~t;"b-r.:.m;r~ilr::.,> ,f+); ,"I?,:$7:;r,$:; ;,>% ,; y cncrgy transnlission from the hammer to [lie 1101 on thc pi-oblcni, presents only the fundn- ,i-y4i,$3i,.:k,:.?),,~:~;G,~,~~~:~z:~::,m?~i, A; ,c: , "/:"j.>'"" CY;-J---+, pile. tip was not instantaneous at impact, but nientals of tlic rnctliod but also a disc~issionof d, 5, g; > +!,:,>,;;:;;?,$;;:f,$$$ii: ,...-,...+ ' +r.-.....- r;y 5 rather that a \vave action occurred in the uile. car, , ,;;!;,5:y .~:t~j,*y~!~~>>i~:!;;;::;; tile simulation. ~i tlic Ii;r~nriicr.the drivine0 -~I , :iflcr the impact, sp that the behaviour ot tl?; \vitli capblock ilriil ccisliion, tile pile, aiid the lianlrner-pile-soil system during driving \vould soil. In ~~nsticulnrSrnitli defines in this paper !lave to bc analyzed by applying tlic theory of 311 the pi~r;lrii~~tcrsiiivolvcct in the sirnulation \\.:I~cpropagation. Wh!le the niathernatics ol arid . gi\.es tyjlical \.alucs resulting from hic rliis theory \vzs well knr)\vn, tlie solution of the csl>er.icncc. in applying.. . .. tlic \vavc ccjuation rile dri\.ing problem remained impracticable- rnctliod to n vi~rietyOI pile tlri\!ing case his- iL until 1950 when tlie development of computers , - torii's. hlost of the ~iiatcsinlnrcsentcd bvi- Smitli~-~ rnads tlie numerical solutio;~of the \vavc'equn- ( 1960) can be used directlit in the solution of tion possible within an acceptable amount of prnciical psoblcrns. 'I'ile reatlcr is referred to rirne and effort. It is unfortunate that, during tlirsc refercnccs for a clctailcd description of [hi\ 70 year period 'much effort coritinucd to tlic wave cclu:ltion ~ilctl~od. ne put in the dcvelopnient of thc pile driviii: Many invcstig:~tioilsoil the use of tlic \vaT:c ~orrnulasin spite of their funtlanientrrl liniita- ccluatic.rn inetliotl have bccn cari-ied out siiicc ! *.... ,,,,- ,,,. , '.":,!',.\'.. '1 '. ii011. ti?cii. .I'iic). \\.c.i.c genc.r:rll!. ai~iicrlnt tlic ii~~iiysis 1 $6 , , ,,,, ,,+ ,(.;. - *.":- .. 7I;; ,;.h, 2f '; ,d. ,-':, ' P'hen a hammer strikes a pile, an cl:lstic of i!ie pi~:.anir.[crs in\.ol\,cd in tllc siniul:itic,n ..,,:,.,,to ,... ,?,,,), .i'+: d.,+;yyL:i a.r! ',y.:.,*t :: ,,i>-,,?:$,* +.7j ,.#& >, * 1 at tlre pile lierid. Will1 tinie, of Iianirnc~rs, i.nl)bloc,k.;, c.!~\liions, nnil soils. ;>;<, :p,,:,p,,-i?i,.5!:':, -?: , . /. * , ;<;<::, !,?$ ? ;>.% ?:,*r;, ,:J> !Itis 3tra1n progresses longituclirially tiirouizll Foreliaiicl niici i . - ., 1 !>) ;;:?? ".:'$'$i', ,::.> " ,,, !,,? f ,+ , , , . + , , , , , sidcrcd, ;irici tlic ~-~:s.!~lti~i~SL:I:C of the art relx)r.t .- h\~;~~!:.n I,?;!?~ .'lIL,b ,, YllU 'L ULC ,ILL Illll.>J ULLIJII", LLII .i first' numerical soli~tio , . Y .-, :~\iny a simple mociel fc . . .<.*! t!' 1. ry ;cl,~ti\*elycrude at :tiat stasc. In :I st.cuniI ~>;tpcr :rii;~l!~~isis iIisrt JO~L,~! !:cl\\,r~~-ils( I007 ) . $ I ...>;$$j::iLY&3?+T:i ? (,,,; &,,l:,.,$:e,:,?&,w ?, .imith ( 1955) applicii tile method to thc ;~n;iI- '].lie oi.i~in:rIpr.~;:r;~ni i~ic~l~~clt~i ;I provisio~i for . . ,.a,;#a>' vpL9q.IL, ivk-~ y,i . ",,:?$$ jik:.:r,~P . #, ' J,. .., , I,!, ;x??2,;,:tc ;,: \sis of impacts bct\vcen clongitcJ struct~i~.al .,ii:iul:iting iilc cl1'c.i.t 01' ili~i~o~itiri~iiticssucli as 1 p$>* {;,;:j.1,:,s ,??, >-,*, -.<*:ax>Yi:: c.ienir.nts and considerinq the problem of siriiu- ioiiit~01. tcniic?rr cracks iii the 17ilc on the ., i.x7 &;- ,! y,t ,T -;,ii,~ y;J- 1 ;;;:<',A b .. 4*.", . .*<'pir y,,F$::c '-* . , 1.11irigcushions. In 1957 ~nijtliprescntcil the :~.i~~~sriii~sicl~roI. tci~cilc fc1ri.c~. A's di~cussicl ;:..i $wc,+,4?$:#$;,,,,&-, t;,!gGic'!,$$$$7i+ ,:; :fqults of \\.:IL.cequation analysis for psctlicting lai:.~., il1i.r 1.1;rrt cif tlic ~)rogi-;~~ii\vas niodified to ,?;;:, , :. ;tw2p2rL 3r,rf:.yl~;: ?. ! - . ,,,, ', :i:,'.'>:- v.,;...y ;;,, ;;P;;? IY ,Ilc vari~itionsof pile bearing capacities \~ith alv, lahe into nc-t.\)\rrlt tlic ctfbct of sucli tlis- i. *,-. :q!jL" f4$.:::;ye yy2;?3b.t;;;7 ,L 2y:.9, il to,,'$R%L~ ~',.'.,'Y, '-iving resistance; he concludccl ~liat''ti~e cn~itinu~tichon tlic tr:~nsliiissio~lof cnm1:ressive , , , ,! !;:?-,>.;; ,l;":p;,,.:~.~:,w>A't-;,;; .'i ,,,, >: w, .. - ,,v,virJ .:!I&*;:L? Y bcciuired abilitv to solve tile iirave ccrii;l- for-ccs. ill (ircIcr to siniuIi~t~~i~roi)crIv tile I?c.- jm+,,; :; :pl<;,y:fi!. h-tA!;<-;j ,::;,: (',\N. GEOl~ECii.J. VOL. 14. 1977 ha1,iour of ~licclianicnljoints in prccast con- diilitieci into segments and is, simulated as series of masses, representing tlie weight nf [' segriients, connected by springs, represen1 :: hfo(l(~lit?,qof [llc i )ri~,iiig.S~Y~L-I?I the stiffness of the segments. If the pilc The dri~ings! stcm uhcd througl1out this jointed, a slack, corresponding to the pn~qii: investigation consisted c~fa frcc-fall harnlncr loosrncss of the joint, is spccifiicd at the c,,. and :i driving cap with cap-block and cu.;liion. ncction bct\vecn the two segments on each c!, 'l'he Ilnn~nlcr-suscd we!.? s1lo1-t so that their of the joint. The restraint ollerctl by thc $1 oLvn elasticity cc\~rltibe nc;:icc:cci. They \vcrr at the pcriplicry of each pilc ccsirnent or bi.11, thcrcfor.~:iniulatcti ns ;i niass ]/'(I ) faliing :he tip of the pile is rnodeled as an cl,~*r~ froni n liciglit I/ to ~?roduccrtlic dri;,in~cncrgy pl;istic n~odel.Thc yield displacement is callr \vith an ciiicicncy. c. In tile abxcncc oi ;In? the quake Q, while the energy dissip:lticln dircct mc;lsurcrnent. tlic usu:ll \r;~luc 01' c = thc soil is rcprescnted by a dar?iping conqt.8f 75%, propo\t.!l for f~cc-fill1 h;~rnnicrs ir: the J. Thc amounts of point resistance and sli literature, \$,:is first ~iscd.I loivcvcr. tlic nn~ilysis friction mobilized are specificti in tern14 c-rf tllc inst~-\~~~iccltciipiles indic.;~tcd ihrit an pcrccntagcs oE the total driving re$ist;:t>cc cfticiency of $5'2 \~~:lsnlorc rc~~~-escnt;iti\.eoS Figure 2 shows the model of one of tlie vii,. the system, ant1 lhis secor:il vnluc \v;ls uscd for considcretl in tlie present study. the cntirc invrsrig;ition, l'he piles nerc generally ~iivided intcl 5 : Tlie drivirii.! C;I~cori~istcil of a SIC'L'~l~elinet (1.5 n~)long segments. Tlle prrcast conc:rr acislline nh~ut1500 11) (().(;7 AX), c:irryiny o.eigllt and stiflncss ,lcl.c ilclcrnlinetl ;I c:il'bIock of <]I.!. II:II-t!\\.oorl. 'l'he capblock dircct mcnsurcnlents on 3 ft (0.0 m) Ions IC.. Ilad nn iililial J~ciglltof 0 in. ( I5 ~111);111i! 311 , spccirncns, cast, cured, and storcd in the arc2 of ahout 124 i11.V(S(l0cm". To c:ompi~tc :lie stiifricss K( i ) /1 1::lI. oi [lie c:~;lblock, - FlLEA2 , MCEL the cornmon n:oilul~rs v:llur: c~f45 000 psi (315 kPa) proposed b!, !.o\vcl.). cc ol. ( 1969) \vns first ~lsecl, to obtain f;( 1 ) - 930 000 1b:'in. !170 000 kNjn1 ). 'l'llc \tiifl-lcss I<(] ) \\!as tlicrl vnrietl :is part of a iinii[crl pill-amctric nr~al!.sis on tlic irl~trum~ntcdpilc.;. 3rd ;I liiglicr .. - COP~IDCI. -.. .. , \rnluc of K ( 1 ) i 500 000 Ib/'i11. (160000 - *IZI,EPES'? kN/'m) was fin:il!y sclcctccl as nlorc rc;~rc~entn- S~ACV~L Lo\vcry rr (11. ( I900 ) . A cushion \v:~s~,lnccd I)ct\vccn tlic liclnlet and flit pile Iic:~d~\\llcndriving precast concrcfc pilcs. This cusliiori consistccl of ~iinsonitcplates ~~~ith;~rinrcn of 12-1 in.: (SO0 ~1113qnd ;I total initial tliickncss of I in. ! 2.5 CIII ). I'lie proper- tics of ninsonitc \\.cr.c ass~~rnctl\inlil;~r to those ol' asbcsto? cliscs nntl \\-crCt;thi.n fi.om laowcry cl (I/. (IOhO). .2cni:1 hcst~,tlic resulting stiiF- 11css of tile c.ubliic>~~\\.as \.;lr.ic.d in n paran~c~ric ;~nn!!.sis, arid ;I Io\\~r\>'~luc \\;I'.; linally rctairiccl. This res~litctiin il conlhirlcd siilTr~cssK(7) of tlie cushion anrl [lit first pile cltrncnt 2 000 000 wnl ,.*,'lOnc, Iblin. (350 000 I,Y,'m). -1'11~ ~.cle!iicicn: of restitution of the cilsllion \\,as cli~scnns 0.3. I~o(/P/;~I~I;IC Pi/(*-.70i1 .~,v,~tc~t?~ FIG. 2. Typical niodel of pile for ur;tve cqti;111011 In any \vavc equation n:lalysis the pilc is ;~naiysis. TAVENAS AND ,\,[JUit<[:I<'r TA~LE1. Pal.an~clersused in the wave cclir:1tic711 an;ilysis - - - Drop hatrirtlerr Weight IC'(1) = 5580 to 7500 Ib (24.5 [o 3.1.7 kN) Drop height H = 1.25 tu 3.5 ft (0.38 to I .OS 111) Efiiciency r = $55; Drici~gri~p Weigtii W(2) , = 1500 Ih (6.67 kN) Capblock stin'ness A'( 1) - i 5M1 M.M) Ih!in. (200 000 kN/rn) Capblock restitution ERES(1) - 0.5 Cushion stiflness K(2.c) 3 WO MX) ll>:i~i.(250 O(X) kK/ni) (I(> I>c comhiiicd with thcstill'rics.; (A'(? - p) or 1111: first pile cleriicri!!. Cushion restitution L'IILS(2) = 0.3 Soil Point quake @ = 0.15 in. (0.40 cm) Side quake Q' = 0.15 in. (0.40 cm) Pciat damping J -: 0. 15 sjri (13.414 s,'ni) Side damping J' = 0.05 sift (0. i 5 s'ln) Point rcsistctnce K,, - 20x to 80% of (niost ~rcprccriiative value = 407;) \\ay as the actual piles. The Young's niodul~is c:~libr;ltc ill~\\avc eclu:ition ~lic~~li'land to dc- of the precast concrete piles a\,craged itrn~iiietIic1~;1i.:1111ctcrval~~c.;s~;o\~~nin~;~b~~I. 4 000 000 psi (75 000 kFa) . I'hc clsi\.ir~gfor~:ss aiit! iiitir~i;~tcbearing calmci- ic soil quake and daniping are ilillicult to tics rnc!;~c\lrctl i>i; this j)ilc as well as or1 tile ure directly. Fortun~ltcly their intiucncc otlicr thr-cc ir~~t!~lriicntct?piles \\ere [hen c01;l- on the results of the n!~r\lysisvb~s shn\sn to 1~ p;:rcd I(.-, ~licva\c eqriCition I,rc~lictic~;~s. \.cry limited by vario~lsinvestigators. it is thus 11:e accepted practice to take the \.n!ucs of C'i!;r?io;t> (.(I~J,~~.I[~~J't~c(/i~tiot~.s quake and damping Isam the tables pul~iisht~l Encli of the instrumcn~utl piles \\;crc ;~na- by Sniitli (1 960) or by Forthand and Jiecst I! lcci ;it v:~rio~lssiagts ol' i)oiict;;ltior~ in tiic r 1064). For piles ciri\.cn in sand, it is yilne~all!~ sand cIti)osi(. i'igur~ 3 slio\\rs tiis \,ni.intions asreed to use a quake of 0.1 to 0.15 in. (0.25 n.iih c!cptli elf l11c Ilcilririu cal,;ici\ics coniputetl to 0.4 cni) for holh ilic point and sicic resis- f~.on~tlie obser\.cti blow c,ounts; also slio\\,n on 1;rnce. Similarly tlie point damping constar![ J tllc fi!:ure ;Ire tllc i~ltiniatcI)cnri[lg capacities i\ comniol~l! taken equal to 0.15 s,'ft (0.4 n?e:isilsccl iii tlic load :chis on \he 'fully driven s ni) and the side dariiping constant J' as 1, 3 piles (tlie loaci tc5t on rile C1 could not be of j. Tlie utio bet\r,een poirit reristancc aiicl con(luctrcl 1111 LO i';iilurc). skin friction can be evirluated from thc classical 7 lie "g~~il~~itbct\vec.n prtdictions and ob- bearing capacity forrn~ilas;the iiifluence of this scr-\.:~tiolisis rerni~rkable. \Vliilc s~icli agree- parameter on the coniputed dri\.ing 1.e~istancc 111('11t \\';IS to 1)~csl7ectcd for pile '.? for- \vliich \\ill be sho\\.n during the nn:ll!.sis of tlic tes: tlic \~.:IYC eq~~iitio[i[i~oclc! \K\S ci~lil>~-ated,it is piles. c(Iu:LII). good fc)r ~'ilc's('2 :III~C.3 in spite of The final valilcs of tiit >ini\~l;~tionpariim- tI;c ~lillcrcnc.csiii pile li,ri~ili.dcptl~ in sand anil tiers used. throiiplioui ihc pre5eiit study :ire l1i11ii111c.1\\.cigliis, 11111s~l~~iloi~~t~;~ti~ig tile cju:~l- ~urnrnarizedon Table I. ity of ilic ;111:1lh~i.<. It i'; ;iluj il:t~rcstingto not^ that the coni- An31ysis of the Instrunie~ltcdI'ilcs ;1:1;cd karing c:~p:icitics i~~crciiseIiilearly witti During the construction of tlie foundation, dc.;)tll cio\\~iio :I dcj>tli of ahout 30 ft (6 nl) four instruniented pilcs \sci.e drivcri and test ill ilic sa~itlclclyosit cori.c-slxjiidilig to 20 piie Iouded to investigate the driving behn\,iour of c1i:l:r:ercrs. 13i.l0\\~ this rlc;)l!i, the con~puted .>st concrete piles in sand. Tht. inforniniio!i ciri\,ing rcsis[:iiiccs renuin marc or less con- d' 'led on vertical pile A2 was first used to stant. Thus it \vould appc;ir that the concept bt0ll.q com'.!)l .R",l"", are \vitIiin 230% of a perfect correlation. o m RO IW PO 140 Considering ihe difficulty associated with dy- ! natnic stress measurernents in a comsositc pile -. scctio11, the quality of the stress 'prediciion from rhc ivave equation analysis c8n be cori- - sirlered very gcod. The tight control of the driving conditions has certainly contributed to tlie quality of the stress predictions; under I - mrrnal liclci conditions where such tight con- , -. test loading program carried out as part of the design included the analysis of a steel F-I-nile i 1~ (referred to as pile 1-1) and a Herkules preiasc I co~icrcte1i1; t!ye 800(referred to as pile w -- . J), driven and test loaded iri succession to dc~ilisof 3, 13, 23, 33, 43, and 53 It (0.0. 4.0, 7.0, 10.0. 13.1, and 16.2 111) into the 4,- L sand tlcposit. 'Tlic details of this proi!sani \\.ere ~~'chcnteclb!: 'ravenas ( 197 1 ). The t\ito piles JO _LA--- have been analyzed at all stages of pcnetra- tiori hy IIIC;II~Sof tlie wave cquatiorl iilethod. I-'I(;. 3. C:ornpt~!ctl ;~ric! ol~.;er.vctle~li/r~i:~lc c;lp;lcilir\ 'nic'cl p!cc:151 :onclcIc piics. nl,),if1 ~tr(iItip~i~ PII~(IIII~IC~S ,-. .,> ,,. >";<*.,':,.. !".:.,'<3 111 ) 2;p&~~;~:~ ;$ $ nf ,-~-;ti,~~l,I,x,,~I, ,,,.,,.,.,L~~ZI I,~\8t5ic (1967) 130th piles consisted of a first 20 ft (6 loii!. scction and of additional 10 ft (3 111) '\11lt5 [~~.c'~c'~itcrIby not (>I~I!: tlic \tatic 1011~sections. For the purpose of the analysic [lie piles \\,ere divided into 5 ft ( 1.5 rn) scg- i ~111cli>ut ;11w tlicir ~.alilelitl~ hcir~g rhc rlicnts sr\ [!?at the joints in the piles could he cntil! siriiulnted. .d2\L r,, L,,,,,, L<,,L.,. 'I'hc tlrcjl h:lnin~er used to drive the teh! Dri17itlg ,~'I?(J,Y,YI~~~C~(~~[~II'O~I.Y piles Iiad a \vcig!it of 6300 Ib (28 kN), and I=i?i~i-c4 she\\..; tllc ~listrihl~tio~i.;of tiriving the drop height \vas varied from 1.25 ft (0.4 str'cs~csconillutcci :I[ I\~.o$[age$ nf 11c11c'tr;itic~n nl) for the d~.ivingof the first two sections of 01 pile t\2. Also >I\o\\.ii oil the fi;urc :II.~tiit the concrete pilc. to 2 ft (0.6 rn) for the ctriv- correspondin: strc\\cx oh.;cs\~c~ciin the l~ilc. ing of tlic last colicrcte pile sectioi~ and to -T'iii. ;iysccnlciit in l~ltll~n:~yuit\ldc ant1 r1ihtl.i- 7.33 ft (0.7 ml for tllc steel F-I-pile. Thc dri\,- I is c I I ~iiI I I- ing cay., had a \vciglit of 1300 Ih (5.9 kN) \cr\.cc!, \\.ll:ch I~;I\ Iw j~(~.;~.i'i~ly;I~:Iillurccl to ant1 car-ricd a (1 in. ( 15 ern ) high sapblock of (Itiic ;IC~':II-;I~.,..of !I::, <::<<\ 111\':1\\1~iiig<\,\~e~ii. li:~rdit.oocl. .*I I ill. (2.5 cni) tliick rn:~sor~iic Siliiilar ~~~x~rlts;\c~-t olll:~i~~ccl Tor all inslru- cu~liio~i\ras uscd kvhcn driving thc prcca\t mentccl piles. concrcte pile. The input parameters for the Tlic clri\.ii~gstrcsscs coiiir~~~te~lat ~iic difTcr- dri\.ing s),stcni n.cre rakcn eclual to those rc- cnt st~gcsof ~lcrictr-;~tioriof pili.s ,\7, C1, and sulting fro111 rlie first analysis and given in . . C3 ;Ire co11i1~;1scd10 tllc c~orre.;pc~ncliqstrcss 'T;lhlc 1. obwrv~ttions011 [:is. 5: tlic (I:II;I for pile C2 111 or~lcrto evaluate the pcitenti;\l of 1l1c \vcrc 1101 uscd l1cr.c I)i.c:~u\cof 111~;,'I battcr wave ccluation rncthod for tlie prcciiction of of [tiis pilc viliicll scsrrliccl ill rrralic ?tress men- pilc capacities in ~hccommon case \\.here no surcnicnts. As cn~ibe sccli. j~ractic;~llyall ci;lta preliminary information on the soil p,lramctcrs CAN. GEOTECM. I. VOL. 14. 1977 Figt~re6 sIlo\\s a typical scrics of results in of pilc H had been obscrvetl during the in,(, terms of the ~ariationsof computcd ultirnatc pretation of the load tests and Tavenas ( 1 Y7 1 and nl:lsimunl computctf c;~paciticsis in the resistance. order of 5 10%. ancl. [lie c;111:1citics ohtaincd In spite of this loc:tl problcrn, thc bcar~il. from the precisc inj~utjli~r;ti~lctcrs arc witllin capaci~ypredictions obtainetl from the \\:I\ 5 t (45 kN) or ~Iicobscr-vctl c;ljx~citics.1-nrgei. ~qitatio~~analysis are excellent for 111(, i;rl,( de~iiitionsbct\\,rcri tile conlputcci a[) ------Tc71 Ilci-th in Quake Point reqistance No. sand (TI) (in.) contribution ("6) TAVENAS ANI) :\l'i)I111:RT ultnrnote .wriy CR>OC.I~, tons 80 lr0 120 140 I I i I I I FIG.7. C'on~puteJand obscrvcd ultinisrc bcar-ii~gc:ipacitic\ for steel 1-l-~cstpile. uitlrn>*t bcDrlnp CCWC,~~,~onr LT 40 ffi LT I%? 120 14C I63 1%) 203 cwnp~ledrnon~inurn :o&~~cI!~ -. ~-",s,~,J>~o~,~,C.s'~~S co,.,c#,y <. on,.,*.* "'l.,"Ol. C,IP I. CCrnP"~. 50 -.------. - FIG.8. Conlpl~icd:inti obsei-vcd ui~in~:itcbcariiig c:~l>;lcii~csfor. [>rec.;cst coricr-ct~[t..;: ,,i,le- no joint siinulatio:~. . , ultimate bearing capncitics are consistcnti)! c,:!lc.r only aftcs ;: givcl~ of the jt!ints on the clri\.il:g bi.!ia\,io\:s I)!' il,c.. :~r::i!!sii \iclt ~:i;~t.tic'all!. iticrltical to tilose of l>ile. As a nest step, tllc ji)irlt! \\.c'rc, t;\kcli iiito ti12 Iir51 ;III;I~>S~<\\itI~o~it ;:>i~il si~lit~l;~tio~i, 1-his acsc7un: b!. assuming tliat tli~)-\\.~ulil 5~lioq.l \!~I;I>IL' i0i11i \il~;i~!;\tit~~i 111~s110i reprc- immediate transniissio~~of thc cornl~rc~\ioll s~\lit;~tii.c01' :he licltl bcIln\~iour. torce \save. but that :IIC tc~lsile ~OICYS\VOLIICI '1'11~ Ilk r-<~~lcspile.; used ill ill? tcst I>t,(>griiill - bc. lrallsnlitted from one pile sectiorl to tlic \\c~-c.ccj~rillj?~tl \vitli a cc~itralir~spectioti pilc. .. . in ortier 11, kvell tile pipe (.ll.;sr~ :lii~ldry. thc ;ind :1r?lou11t5 lo about 9;; ycr (1.01 ill inere lclI I I!01i1 so i: (0.25 nlm). tlic f;lcc\ of' rllc pile j:~illl \\21.c 110t in sc3litl 111 order to correctly simulate the ficltl 1~- ct)rl:.~i't initiilll!,. :\.; :I cor~wcl\~c!iceit is most linviour. the 111ngniludc of bidireition:il ~I:I<; I itI iiiI i~tiI i in tlic lest piles was 1:lkl.n cqlla! IO Ilnlf ri!: 11it I I t lcCI 1 I ~c>il~it.ll~ii~~~~O~CI.;II~CC OC the fl<.lk~llesjoi111 lr:11~~~111is~ion(31 111c c,(l~~~l>~.r\\i\,crorcc \\;i\,c . \Villi lliis IICW ri~ociel.tile \vavc r111.1atii.111:lrl;il- to tlic lo\\cr j:llc c,lv~~?c\iitc.,l\:lcl occilr. '['lie !sic. rcqt~it~dill significant r~ducti~liof 111~ I rliI tiif1 t I j>rcclicrcd capacities of tl~c pilcs. Figr~ic l I 0 1 1 I I l tCI I-slio\\.s tlic cfIcct of tllc joints (111 tlie ulti~ii~~!r I i I I clI iicio1:11 capacity 1,s. BPI curve for tcst 71urnbcr J-5. s1:lcIi. tlie prcxnce of four joints with biciircctiorla! In orrlci. to c\nlr~:itc ~lic~:iic~.t of a joint slack rcsults ill a clecrcase of tile predic~ctl \\.it11 a I7iclircc.tionai :,lack. :I tlcr;lilccl :~nnl!,xis il!tir~iatc capacity in thc order of 20:;. a~ltl of n pilc i\.itli ori~.joint \\:I.; C:II-sictlollt. 7'lic . . the capacity predictctl from the jointed motlel ~iiilcllc-of tl~cpile and is rcniar-hiibly close to tlic result of [ti; icxrtl i~i1i01i I c if.i- test. TIi1s clrect of nlcchanical j~~intson tl~~, LC( I I ItI' L I inI dt-i\.;lhilit!. 01 1)rccnst cnricrcte p!'c.s is c.~:\- 1 01111I! lltll I i!ci5tt'lit \\ill1 tlie cspericncc I'~[V?i'i~clb! :\:I i : I iiill I I S\\c~lisI~Pile Corr~nlissioll ( 1064). 7'11~rlli111- 1 1:. I ! . i I I 11ii11I' 1 co~i:~~111~1111,~ii~lxi~il~l~i~. ;111d proballlc bc:~rinsC;I~;IL- illll~x'.lill llic joil!t t.:111 I>c. ol~~c~.\~el.\v!li~.l) itics pr.:'tiic!ed from [lie joirltccl model for r11c rCs1 I i~li~it!~II of I sic six [cst piles are sho\v~lon Fig. 17 alorlg \\.ill1 of tlic I'i)rcc' 'Tlic rcstilti~ijr cIl'ci.1 of [his tllc rcs~~ltsof t11c load tcsts. ?-,lie agrcemcnt bc- is11I' I Iicilil~~I I I ct~~1\\,cell ~IICpl-cdiciior~s ;liici ob FIL;. 10. ElTcct of the 1i:ngnitu~leof ;I triilir~~cri~~~;~~ 0llrl-p rrr.lo"r. ,BPI slilcb on the cornparetl ui;ir:latr: be;:riny cap;liiriec. I-'IL.I I. (~OII~~IJI~~L~I<[ 1,s /!I1/ (c,~pl~p~:,s~ Lc,,,cre re IPS1 pile \\ll~1011~,111,l !\ill1 joirlls siri,~,l;~[i~~, mate capacity usin: coinliloll values ciF the e parameters is in the order of +- I Oi'; . i.p. ac.tu:~i c.ncr.tl,! LIcIivcrec! to tile 1,ile by cacll 1.. .!ctIy acceptable fur any practical c:i,e. Iliimni~~blo\\.. .l'iic ciri\.ing rc~cortls of :tbout 500 prtc:lst Analysis of the I'roduction Piles concr:.tc piles :iri\.cn in [lie Il~~nlogcnco~issar~cl 111/ro(l~~(~tfotr delx'sit ;rt tlic Snillt-C'I~:trlcs liivcr siie 11n~.c 111 the first t\vo phaws of 11iis ir~\..esti~;lticiil, hul?p(~rtc~lthis ;r\\urlll>tion. As reportctl by rhc :eliability of the \\.a\,e ecluatioil nietllod for 71'a\,c~l;~x;iiltl ;\~iiiy ( 1072 I, Ilic obscr\.ed vari- nnal!zing piles driven unclcr tiglltly c*ontrc~ile~l ntioris of tlic driving crlci.gi~~:isc estrernely field conditions has been ,cstablislicd. j-Io\y- \\~cle. \\ill1 . tlic corl~putcds~:~rldarc! tlc~i:~!ic>ns e\.cr, the dr.i\ing opcl-ations carried out ilaring rnrlglrlg i~oln33 to .15:'.: of lllc avcrage \,:llucs. normal piling jobs arc ~o~crnedriot o~;ly b!. Since tlic \\a\.e ccjllatio~~11ii'llioci ~f p1.cdicting qualit\. rccluircrnents but 2/50 by cccl~~orilic pile.' c';~j):~citicsis bn\ctl 011 tllc a~surnl~(iol>that considerations ancl in particular a search f(7r earl1 1ianirnc1- I>li,\v dcli\,el.s tllc rated cricryp, productivity. As a result, 'the ciri\,ing ~oncli- and since it 111:ll;cc iiw of iilc standar.ti hloiv tlons are generally leh.; tiglitl>~cantrollcci for count, i: scc~ll.;likely tI1;1[ tl~cob.;i.rvcd vari- production piles and large \.nriniiorls arc. uii- :rbility of the driving ciicrgics slloulti l>c rc- ;r\,oidablc in such importan[ I~al-;1nictcssa.; tile flcctcd or1 tllc I.CSLIIIS of the \vavc ecl~r;ltio~~ ;111;tl! \is. quality. tllickncss, and rigidi it!. of r!lc ~.al~hlocl\\ . arlil c.usliions. in tllc ;tctu:~I drop Ilcigi~!,. ill f\'c,~;c/~.\. :lie rl~!tl~n~ drivi11;. iliici in tlic ;t>l~!ii~,s 111 oriicr to \cril! rllc rclinbility of tile \\.aye cllicicncy of each Iln~llmer blo\v. 'I~hcrciorc, c.cl~r:~tionfor illc ~)l.ccIicri,,~~of tllc ujtim;l[c ca- clri\ing resistance measirrcnlcrlts dune 011 jlro- l~acit!, of l>roilriclio~lj>ilcs, tllc 111ct11od ivns ~5~21 of ~Jucrivnpiles by [h? !?lf.:lIlod c.!)~~f!l:~!p i:?~l,'i(:(j 10 39 \!;!I.:, ,!rj38t:, lji(: ~;;j;l~-[~!,;jr\*;:, it~chammer blows per ~rriirlenglfl of j)erlcii;~- Riper site. :~rlc! for ~vl~icliftjll '/riving rccc~~~i~ tion are likely to be alTcctctl b!. 2 random cr ror :is \\.ell ;IS loat1 ttS\ts results \\,cr.c :~v;iii;~ble.The ccluilralent to the rarlciorn vnrikttion in' thc precast i.o~lcr~lci~ilcbs \VCS~ Silllil:lr 10 tilC Her- t -,;,?:L;%\-> " , .? +: $,-~-+$:. ,;<.++ ,+,,$:< ,4,-4 FIG. 12. Cornpuled and oI~sel.vcdultimate hearing cnp;icities for precast concrete test pile ,y,;? qL;,~,~g~;;kT wilh joirits siniul;~tion. -> 1 2p &gJi;(;s&:.$-*,y>f.- :y kules FI-SO0 piles described c;iriicr; tlicy \verc driven by drop li;~nimcrs,using c~ser~ti;~ll~~[he same cc]tripmcnt ;IS ill tile test proi:ram. Con- scqucntly, the s;inle iuput parameters used in tlic analysis of the instrumented piles (see Table 1 ) lverc applied 11cr.c. 'fhc cliaractcr- istics of the piles 21-e given in 2, Also given on this table arc the ultirnatc bcaring capacities Q,,,, obtninctl fr-on1 the load test car- ried out ancl interpreted by n1c;lns of the same $ tcchnicluc :IS that used during ~liodesign test- ing program. Fi~i~~ll!:,the ~~ltiril;~tcpile capac- > itics or,, olltaincd fro111 the \v:~vc ccluatiori " analysis and tlic rnc,~surcdtlriving ~.csistancc,c arc ;~lsogiven on 'l'al,lc 2. '1-lic r.chults are sentetl in the form or [lie rcl;~tionbct\vcen the computed (Q,,, ) and tlic riic;~suretl (Q,,,,) ~rlti- mate bearing capaci~icsor1 1-ig. 13. 7'11~nide scatter of tlie dnr;! is ob\,iorrs: I6 out of 39 data point5 arc outsicle of tlic :t3052, limits. with a nl;~rkcdtcridcnc! for tllc \\a\*ccquntion 0 a w ec w ,KC IZJ ,a .MI lo tlr~dcrcstirn;itctllc pile capacity. 13y mcnris Q,-,-au.d.- of :I Ic:~st s(lu:lr.< ;~~ij~rstrlicri~r~lc'tllod, tllc re- I:IG. 13. Comparison of ultimate cnpnci~~csoh TA~LE2. Charilc~cristics of ttfs~~dpilCS 1 42/12 2 A2/13R 3 C3135.5 4 C1/676 5 C2,'1029 6 HRjlll6 7 C2/1254 8 C3/1260 9 C1/1521 10. C2:1602 12 C1/1636 13 CI/68 I4 A21307 15 A1;446 16 A2, 609 17 A2.789 18 A1995 19 Sit337 20 C3;3431 77 -i C2,3653 23 C2;1790 24 A1/18 25 A2!57 16 C3170') 27 c'2,,212 28 C2,289 29 C1/745 30 C1'925 31 S, 1040 32 C311345 33 C3/760 33 c2;1599 35 C1'1785 36 C3!3506 37 C2,'3497 38 CI'3525 39 S,3537 J 1 40 20 6.30 1.25 14 38 J 2 5s . 30 6.30 I .25 5 2 60 J3 78 40 6.30 I .h7 5 3 SO (1 J 4 95 5 6.30 1.67 I I0 I00 JS 108 60 6.30 2 I (MI 107 J 6 120 2 -- 70 6.30 140 117 *Q,, csiin;~icd. illicstie:llio* of the qllalit~of sonic of tlic tile u.;lic eclll;ilios ixedictiOns no better ll'il;1l 13ilc drivill~f0r11111131. Usillg t11c S:~II~Cset t~~~~~~;lily or ,llc 13sc~~~c~~ol,slll~l~lcby lllc .le cl;l[:'$ ,r;l'e113~ 311~1 ~~~lc~!'11;1\'t ~~t;lblisl~~~i dri\,ills fe~l~IllLl/;ls,}{o,i.c\.cr, [llis Ilol ll,eal, ~:i~ll~'1a~.k of c~~sscloiiaobctrecn t!;~ I,[,- [11:11 illc \~.~l\c~cc,ll~ltic,,, lllclll~,ejis ,lot 'L"'\L'L~ ~1l[i~'l~llcc;tI':lci[i~'s lllld tllc ~:lp.i~i~ics L>LI~silllj>l! [/l;lt tllc cl,csg!. jIll,,,[ is so ,,2siLiblc f lic1 1 I,is. tiin[ it (jestso!i no! \,olue (,f ci.::c~. :!lid rll~di~i~dGals's furniuliis. Table 3 Oil tlli: olilcr ilallci, a caiefui ea;LmiHation of Fig. bulllrllarizes tll~.correlation characteristics be- 14 ill~ic;ltes rllc cOrreliltions using pile liicen f2i1ll) ah. and Qt,.. 11 can be see11 tililt tii-ivi~igf~rll~lll~~~ WCie l,OOr llOt for CAN. GEOTECII. J. VOL. 14. I977 'TAIILE3. <'h;:ract~risticsof correlation between Q,, and Q,, or Q,, Regression lines I Irii CoefIicicnt of -- rc)rill~~Ia correlation (I b (1' b' FNR 0.181 0.052 44.0 0.810 60.8' tiilcy 0.131 0.030 46.5 0.2S4 86.6 Danish 0.272 0.234 100.5 0.387 52.7 Ci:l~cs 0.225 0.081 59.0 1.169 22.2 Gates rnodificil hy 0.253 0.130 67.9 0.727 41.8 Olson and Flaire 39 production piles but also for the six test ities \vithin t lo%, under well controlled driv- piles. 'l'liis is :\I\ i~iiportant finding indicating ing conditions. tli:~t, gi\fen 11.1~proper reliable input clata, tlie The application of the same method to the \~:IVC ecluation mctliod lcads to correct esti- steel H-pile and the precast concrete pile niates of the ulti~natcpilc capacity \vhile the driven and tested during the design testins usi~alpilc driving forn~ulasdo ~iot. program, confirmed tlie high potential of the In their paper Tavcrias and Audy (19721 wave equation to predict the pile capacities Iiad indicatccl t11:1t time elTcct niay have had \\:lien all parameters of the driving systern arc a11 influence on the ultirnnte capp\, CI~ICS " 111~3- \\ell known and kept constant. For all but tlit. sured ill tlic load tcsts, ant1 they Iiacl indicated Inst test on the steel H-pile, the capacity prc- tlic trend of vari:~tio~~of tlic pilc c;lpacity \villi diction \\,as within t 10% of tlic observati~n. tiine reproduced on Fig. 15. In order to clieck For the p;ccast concrete pile the effect of \sl~ctIierthis time cfl'ect coulci nlTcct the corrc- mechnnical joints in the pile was put in evi- I;~tionbct\\,een obscr\.cd anri compi~teclcap:lc- dence, and, lr'ith a proper simulation of the itics, tile \~ari:~tiorisof tlic ratio of Q,,,,to Q,,,. joints. the capacity predictions were also iffithin \vith tlie time lag bct\\ccn dri\.ing and testing r 10% of the observations. \r'ere plotted .on Fiy. 16. No trcncl can be de- The quality of the predictions was quite dif- tected, thus suygcsti.ng tliat if any time eflccts ferent in tlie case of the 39 p'roduction piles ivcre present, they were not sulticicntly great analyzed in this study. One third of the pre- to ob1ite1-ate the ranrlorii vari:~tiolis due to the dictions \yere beyond 230% of the observrl- poor reliability of tlic energy input data. lions, and the coemcient of correlation result- ing from a regression analysis between ob- served and predicted ultimate capacities was 7 - I lie 'experimental data gathered during the as low as 0.1 41. A comparison \\,itti the pre- ticsign arid construction of a large pilc foun- dictions obtained from five common pile driv- dation in tlic ho~iic>gcneoussand deposits of ing formulas showed that the wave equation the Saint-Charles River site in Quebec City, predictions were not any better. This poor per- provided ari cxcellc~itbasis for the c\,aluation formance was attributed not to the method of tlic potential and liniitations of [lie wave itsclf but rather to tlie higlily variable energy cqun[io~i~llctllo~l of l~ilcc:~pacit!~ ~>rcdiction. input. bntli under the \\.ell controlled conditions of a The present investigation thus demonstrates dct:lilcii lest progr;lm and the normal condi- that the wave equation nictliod of pilc analysic tions of prorluctiori iiilirig. is n very reliable tool for tlie prediction of pile LJsing for the \,arious irip~rt par;lmctcrs tlie capncities provided the pile driving system ic c(~1iiriio11v;~lucs prescntcd in tlie litcl.ature kept under very tight and continuous control (I.o\vcry rl (11. 1060 ), the ;iilaI)-sis of the driv- to ensure tliat t-he nleasured blow counts ;ire ing bcliaviour of i~istru~ncntcdprecast concrete truly representative of tlie driving energy im- piles lins shoivn tIi;~t driving slrcsscs can be parted to the pile. However, under the usual predictccl within 230r/;., and ultimate capac- conditions of a piling job, a high variability of I 1 0 40 k' 120 160 ZCO t60 200 C, measured, tons 0, meowed, tons 160 GATES MODIFIED BY OLSON 8 FL FIG.13. <'ornj?nrison of ulliniale c:ipacitics obscrved :~ndcomputcd fi.on1 pile driving for- niuI;:s--39 production piles. ('AN. GEOTt 2 00 I I .* .* 1- .. - . .. . ?>L-A.LI m X) !,me !q I klw?nr bwlnp ~odterI8np tn boy FIG. 15: .rillie effectson the observed ultimate capacities of production piles. , I 0 %XI* S*alc , - I 0 NOIT* MRZ FIG.16. Tinie ctlccls on llic rittio of observed to computed capacities of production piles. tlie prol~cr-ticsof 111~tlriving s1.stc.m ancl of the appears from a practical point of view, to bc ' e~icrgies delivercrl 10 the pile by succcssi\le no more than a complicated and expensive pile blo~vsis un:~void;thlcalitl Ihe blow cou~ilsarc driving formula, at least as far as the reliability not represc~ilativcof the true ilrivilig energies. 7. of production pile capacity predictions is con- iile pile capacity prctlictions ol>t:~iriccl fr-orn cerned. (his vari;~blc input tlnt:~ thro~rgh thc wave I ccjrialiori nicfliotl arc rio rl1or.e rcli;~l>lc(hat tlle .Acknowlcdjic~ncnts 111 lC.1 I I t e I- .I'llis in\.cstig:ltion \\.as initiated \\,]lile lllt 1 1 lC I I is f t~iti;scconti author \v;is a visiting rcsc;lrc]l nssocintc.. 1 I: I I~CSSII :II L>;IV~I Urii\~ersity. TIie lirlallci:il ~11pp01.tof rcsoll to rlircct r~icastr~.c~i~cntsof [lie clrivins the h4inistry of Education of Quebec and the I cllergics: the rnclli<)ii prolx>sctI 1,y Gable and National Research Council of Canada. grant ' ltis co-\vorl\el-s is 1~1sction sucli clir-cct mca- number A-7724 is acho\vledped. The analysis ' surcrncnls n~itl :;lioulcl Icnti to ~)rcdictionsof of the production piles was cirricd out as part acccpt:ible cl~~alit!,.In ~lic;~bscncc of sucl~cli- of an undcrgraduiltc projcct by Messrs. Nor- rect mcnsuremc~rt,(lie \\,a\:e crlu:ition ~ncthod nii~nd'l'oussaint and Michcl Cantin. ! 1 [.:\\'EN IS AN[) Alll)llll.K I 1k1I C. 7 'I11si ;e eii~ en- . -- -- 105.5, 11111);1~1;lllll ~,,!l~l~ll~~lll;l~\\ilve tl.~lnjllli,,iOn, pirlel progr;irii ~rulizarion11lanu;ll. Kes. Rep. 3.:- I I . t..,. I:II~S. ..\r~i. Soc. hlccli. t:ng. pp. 'jh3-073. 1 IIII.. 1 i .A c 1 I\ell tii 'I 1957. M'1i:it I1;1pl~c.ri\\\iicii-~~,~rilmt.r hiis pile'! fllg, Forit'ti.~?.D.1'. u'.:lnd KLr SI-. J. L. 196-4. 1'1-cclic.tit>risof ru'cws I D~:parrct~~crtf(k, GCr~icCiril, F(icrrl/C rlr7r Sc~i~~r~cc~s,L'~rirc~~.sirC LoriiI, QrrPhoc, (?,ic;l)cc. Pic>tte, Alr(!r', t.+irrtly, R~,r.tr.o~rti,trrrri Lcr~~icrts,I~!,oCt~icrrrs Co~rsc~ils, Qrtc'hcc, Qriit~cc. . . Ileccived June 17, 1971 energy equal to !I' X H for drof, halnmers, it appears acii~:~llythat rhc energy tielivcred 11). :1 given equipment vaiies sy\teniaticnlly from blow lo hlo\v. 'This conclu~ion,drawn from LL \tntistical analysis Ies dc bnttnge originc t!iins 1'estirn:rtion dc. I'incrgic LIC b;ltt;~gc;iilors t4~1cI'on :tcl~i~cty2n6rnlcnicni :. .. de h;itt:l.ge au nloycn ds cinq forriiirlc.~tlitTirentes. Lei ohscrv;itions dcmontrent ausi qu'il csistc possiblrnlent un c!l>t tie [enips sur Ies c;~p.~citC:sp~~.t;\~itcs difs ~iciix~Ic biton dans Ic sablc. Introduction Qr = (bV x I1)l.Y .. 'wfoundations being by dynamic dsiving. 11 thc al.ol3 height in i~ .llcs. and S the set ' the idea of measuring the cncrcy necc\\;isv pcs blou in illcl~cs. ~~ltl~oii~l\I simplest to brin: the pile to its final dtplh iri 111:: st>il pi)>>ihlc.. this f,br- nul la i:, no iiiorc. 111e1ltianc.d 1 md of csins \his enerr! to predict 111:: bc:lrin? or ~iiztl,so that \Vellingtnn's Ic,rmi1l:1, also upacity the pile has hcen losically put callcri the Ensincering News Formiiln (Well- :. forward very early in thc history of pilirl:. ington 1x93) ih the oldest one to be \\,ell : The first'~natlisniatical fosmulntioii ol' a knoivn and used. It is still sirnplc but a 45 (..\X.\I>I~\S<;~cc~TIccIISI<'.\I, JC>~~I I' I &"M ! V PlPCX (TCFjS SECTCM ; RLC D3vIffi RAN -- FIG.4. Typical irnplantatio~isof the piles in the foundation. T:iIrE?4:XS AND .%GUY: LI31I'r~l'riOSSOF l)l ofbS 7) ?'lie reI:i~io~lsliij)bct\vccn Qr and the energy lleccssary to drive tlie Iart foot of eacIl pile (fig. 6). which was intended to be used :IS a control nf tlle quality of cach pilc driven in the acti1:il foundation. and of the uniformity of the piling \\.ark. 3) 7-lie rrlntionsliip between I), and the oc~rkul.r H400 tnt;ii energy ncccss:lry to drive the piles in 7~12BP74 1hc sand (fig. 7). ~\~liicllcotiid ~~ossiblybe uzed as a complcmcnt to the scconcl correl;~- According to thc results obtained, five categories of precast concrete piles \\,ere desigiitd \vit!l \vorking c:~pacities 01' 20, 22, FIG. 5. Ultinlate Dearir:_r capacity vs. lerlgth of pile 25, 27.5. and 31.5 tolls ( IS. 0, 19.8, 12.5, in sand tile driving encroy had 10 be controllccl for tile Ins[ 2 ft (.6';;) of car11 pile ;ind tile cniire len_ctll of one every 20 pilcs, :lnd tile cner;jr necessary to dri~,cthe I;!st I'ont of cach j>ilc \r;is spec-ificd in ordcr to cornply ~vith rhe \,:~luesgi\,cn in fig. 6. Finiilly load !learing ttSlS tc) fai!!~r-c \vcre specified on one of FIG.6. Uliinlate bearing c;tpncity 1.5. dri\.irlL: cllcrgy CVCrJ' 150 piics of each category. in the Ins1 roof. !\ 101;11 01' 4160 piics on thc north shore and -;570 pilcs or1 tllc south sl1ol.c had to bc d!-i\.cii. !\i?]~c~iiim;~tcIy70) ', 01' tI1c \vork is :io\v cori~i\:eti.d; 478 f'u11 d~.i\,il~grecords !ia\,e been compiled on thc south shore, and 45 driving a:;ti load be'iring tests have been m:liic on both slio~cs. l'iiesc results 0btclint.d on identical pilcs ciri1.cn with the snnlc cquipnleiit in an Ilornogcncous sand dcposit \\ill be f~~rtlier;~nzilyzed. rir~:kljsis of ihr Ol)srr\.ctl I)ri\,ing l'r~crgies Very c:~r-Iy in the control of the driving i~psrnlioiis it :!ppenred that the observed cncrgic.; l:i~.i,.c! ~rlucll f'ron~ pilc to pile. At tile saint :imc, load bearins tests carried out FIG. 7. Ulrirnatc bearing capacity 7.r. tola! d~.l\irig 011 13iles, for \\,l?ich the crlergj, in tile last foot energy. \\.;IS mucli helt3w the recluired lirnit. showed -- the actual foundation. fig. b IS not unique and could 11ot bc used 5 2 ('.~S;\I)I.\N(;16OTICC1 ISIC.\I- JOURN:\l,. I'OL. 9, 19iZ to control \lie quality of [lie iniii;idu;ll p;les, quencics of 155; and 85(,';, thos .indieatin. and that an analysis ol' the ol~ci.vecldl-i\ring that 70"; of tile obs'ervations are randomly encrgics would be of great intcrcst. disiributcd between the difirent interval<. A statistical nn:~lysis of the ol~scrvations 24s sho\yn in Table I, tl~estandard devi;~tir,ri on the tlrivirig enel-::? ]ins been ~iladcfor 478 incre""~ wit11 an incrcasin? energy and :I piles from the sou:], sliore. 'fllc energies decreasing number of observations fro111 necessary to dri\'e j:,i. 5111, 10tl1, 2()t11, 86 kips rt/ft (35.7 t m!m) at a dcplh of 1 f! :!5tli, and 30th ft of pile in tile sand iin\.c been (.3 "1) 1') 173 kips ft/ft (77.9 t ni/in) depth analyzed anti t!ie foilowinn p:lr:\111eic;-s dc- of 30 (9.1 ni). On fig. 8, the curres reprc- termincii: tllc rninirii~~m,ll~asil~ium nrld ax;cl.- ent ti"^ variation witti the depth of' !iit. ticre of aii c>hser\:l(ior~c;;he bt:(tistic;\l disiri- :!VCr:lsC cnersy plus or minus the stand;ird bution c,f tile ohscr~~d\;aI:~cs in form d~vi"li011 are shown. Their form confirm, cunlulatcti frcql~crlc-~curj.cs: tlic \,andarc! tll" tIlc obscrvcd variabilily of the energy IS deviation and ;he c~cfii~i~nt(71. ijiSpCl.~ioil. n~trel:~tc~i to the beliaviozr of tllc soil in cclu;lI In ?!;c ratio of tllc ~1:lll'i;lrd dCi,i;ltic>ll \\llic11 thl: pile driven but is due to ;i phenorn- to the :\\,crngc. cnon indcpcndant of the tota! energy. ~lic . Fi?. t! gi\,cs thc \,nri:~tionsoft!lc ~niiiiniuni, computeii coefiiciciits of disper-sion vary masirnuln and nver:l?e energy per linear foot fr-or11 0.450 lo 0.225, a value of 0.25 being po~~"i1ytvpical. Such values have to be corn- :IS :1 furi~(ionof lhc dcpkh of pilc in sand. pncd tcl the possible liniits of tile coefficien[ ~~lii~;i\'c;agc c~irrkyincrc:~scs iinc;~rly dispersion. equal to a perfecti) rr- 1 1.15 f ISti 'I-, it- prodllci~,le r~lcllumenon and to ahhul 0.5 vii1ll:ll ob:;crr;itio~li ;lie very I;IS/!\C sc;iltcrcd for :i~,s~,~llle~yilc,n-repioduci,,le or r;ln- , ;lro~lndillis er;l;c. 111~ci1111iil:itcd ~lcqi~cllcy d~~~]~ scalterrd p~,enonlenon. TIlc actu;ll cilrvcs s!ln\''n 011 fi?. '1 f'0r ~2~11(1~ptll 1cvCI 31.r value; indic;ite a phenonlcnon of low rc- more or less 1inc:lr hcl\\ct'll cumo!alcci fre- producihilily or large scattering. driving energy, per foot in kips-fwt 0 5 I0 , . - - , ? 51 '5 a f .-C 5 Q v 0 2 5 3 0 35 1;.8. i>i.i\,in!: vncrgy vs. dcpth: n~inin~~~n>,n1asimtlm. and average. t 'I J . . 5.1 ( \X ~~l~OTl~~~~lXl[~.\~,~(){.[ tllc si1:11c ~~IOLVS[IIC (l~J'o1~1~~;~~i~~:~<>f [llc ,,;1,:. ct?ctr!c ccblt ,--%fyrrilp. -3 01 6" /--,nstrumcnled FI ' ,--steel piore Si '' L--- ,z" --.-.-I VEPTICAL SCCTION 1 1. I)r.il'ing f~rccsnl pilc (n) Ilcn(1 ;jrltl (11) tilr, Sc:ilc ('1 ~~ll(':c~~:i.;iphs.One 5qu.t;e t1;1=. li.r-clll vill. in. -- 3)lolls. I'ilc nunibcr .- ..12-135. pi,clenslll 42 4 ill.. Ici~slllin so11at testing - ?(; r[ ;!I,. ,,.L,icl,l SCCTI~NA-A ('I' l~~l~ll~llcr. (1?SOlh. .dr(~pliciglit .=.:I I)]., c\\~r~~g~,cl j--l(;. llntl~r~b.;cr\ccl hIo\vs = i:, in., avcragc ~,.;l~~ncc~llcnl I('. 1)~i~lll~~(XI'!l1c ]ll<,[[,)l),cll ('.(I [,jIC, ('1' pile h~:ld uricfcr obscrvcd b1oa.s = 4 ill, In all tllese b~rinol;ls. illc constanlc ivsre r, = eniciency of tile ;- 0.8 , selected as Sollo~s\: cording to Whitaker (1971) C' = Constant of the ]lammer ,1 ,, cording to Chellis (1951) C, = 0.15, C, = 0.50, C, = 0.10 ~c;Or ins 10 Cl~cllis(1951) u - 0.25 accordirls to Cl1ellis (1951) if = Cross section;ll a of tllc 125 iii.2 (SOG. 3 cni?) - YOUIIS'Smodulus of tfiz pile = i. 10" I biin2. (42 18.6 x 10"s:n12) T-hc parameters are defined as toll,,,, , I[' -= ncight of the liarnincr In ton? if - hci~htof drop in inches L5' = set of the pile per blow ill inchcs jf', = ucight of the pile in tons 91 = uitinlate bearing capacity in toll$ 'The rnlues of these parameters for t;ici, pil; :Ire given in Table 3. 1- . . Standard Cocfifcnt I I devia[ion of k-fl 'I.[ k-ft/ft k-f[,'ft k-ft,'ft dispcrcion .... . - .- -... .- . -.__.___- I'O ---_ 560 191 S 6 0.450 '1 0 560 750 90 0.300 KO 620 329 9 1 0.270 I Xi 800 41 7 107 0.257 1'10 920 503 I I3 0.2'5 'SO 1070 h(l0 159 0.265 3 00 1100 76s 173 - .- -. __ 0.225 'r,"" I: 2 !'llc tlriuillg iirr~iuii . , Qfcl = el, X JY X II Lnginccrinji Ncii !; (Wellington 1893) StC el, x JI.' X If Qf, ; - -- - .. T.\l'l TAI~LE3. CII;~~;IC~C~~SI~CS01' LCSIC~ pi!cs ~...... ~- -.. - ...... - .. --- . - . . - ... Test Pilc (?f ,,! L \)'/I II lilou.z/foot NO. No. 'Tons I:'ool Kips t..~)ot I.:\\t foot - -. -- - . . ~.. - ... 1 X7j12 67.5 4 7 7. SO 2 18 9 .. A?/1311 90 -1 2 6.7s -7 ~1.1 3 C3/? 5 5 I lo 3 6 6.7s 7 5 I 4 C1;67(1 I40 * 3 9 7. KO 1 -IS 5 C2!1029 1 00 ' 4 1 7.X. 1 5 5 6 IIB: 1116 110 40 '1 . '0 3.5 4 2 7 C"/ 1254 100 -" 40 7 . SO - 3 7 8 c‘3/12ii0 70 3 4 6.7s 7 :I S 9 CljlS21 55 42 7. S8 -7 1') 10 C?, I(102 S5 30 7. SO -7 -1 I 11 C3j1613 !10 37 ;.SO -7 2 I I:! CI!lh?h 1-5 3 7 7.SO -1 '1 0 I? C1,c:S 115" !-.h 7.4s -1 3 0 I4 r\! '307 112.5 .'- i 7.40 -7 3 9 15 :\ I /.:'I (1 S 5 44 7.48 '12 I 6 A 2,000 110 3 0 ;'.'IS 7 2'1 17 i>.2!7SO 70 .1> - 7. SO - 3 1 18 :\I '395 87.5 4 .; -IS -7 47 19 S, 1337 SO -30 7.7s -7 ? 9 20 c- :.? .: .4 1 s.ci .,> 7:;s - 3 0 2 I Cl135l9 '/ i 4 0 tl . 7s 2 .t-', 9 3 - - C2:3653 1 Oil 37 0.73 7 .3 -1 2 3 C2i 1700 5 0 34 7. $0 -7 3 J 14 Xi/lS 112.5 4b ' 5.55 2.5 :[I . . . . - .. .. , , - .,. 35 C'lil7SS I+>? 3 S 7.43 -7 3.1 3 6 C!, 35g6 (,: ? S 5 . 30 -7 3 5 37 C2ilJ97 145' 3 4 5.30 - --?? 3 8 Cl!35?5 I .j 5 " 3 2 5 . 30 -7 45 39 S,'3537 120 'S 5 . :o -1 5 8 J 1 .;!I ? 0 6,?o I .25 IS 17 .5 .< 10 O.?O I .25 47 53 75 40 0.30 I . (17 2 0 J 4 0 5 _C~J h .30 1 .07 50 J 5 1 US 0 0 6.20 2 -i -5 36 120 70 0 . .I 0 -1 I hO -- ~. .. . The computcd values of Q,,.arid tllc cneryy program. Tiic snlc ohscrvntion oi fig. 1-1 deli\,ered to drive t!le last foot oi' piit. 11ar.e siiL)\vs that no \.alu::blc corsela~ion csists been compared to [!ie ncasur-cd altiir?:~:~ bct\\.ecn all! of the computed hearing capsc- bearin? capcAity QrlI,. The resul~sobtained i~ic:;;li?d .. T:\Vl of the corfticie;lts of corr-elation !ill tlic IIIC~ISU~~<~static bearing c:~pacities dc- have been ccrnp~tcdare _given in Table 4. [ermined b!. !uacl tcs~in?were on some oc- All these results confirm that no correlation casions mucli s~nnllcrth,~n cxpccted as corn- can be found between QI, and 21-,,, for the pilied from driving forniulas. 1,'arsons called piles ~csted,and that all five formulas are this plienon~cnonof tl~ereduction of the soil similar in their inefficiency as resista~lce ;irounci tlic pile, "relasation", the coefficient of correlation vary from 0. 13 bitt f;:ilccl to pi.oposc vnl~tablc explanations for the Hiley fortnula to 0.27 Tol- t!ie for it. Danish formula. Yat-13 (1970) has rccently aiialyrcd very These results arc in coticordancc with tiic e,xtcnsi\c!~1ili5 rcIa\;llicin ~~~~~rl~il~cl~ol~of obserisd scatteri~gof th? drivinz energy on piles in s.;ilic! and silo\vcd tilat porc-wa[cr ivhich the formulas are based. Therefore. it pressut.cs :IS \veil :!.; cll;lllgcs ill the soil can be concluded that for the type of piles structure after Jri\.iii:: clbi~lcilend to varialiotis tested the usual drivins forrnuias arc of no of the driviil~ rcsist:l, :e. Invcstigatirlg the practic:iI F'alue, not because of an erroneous influences 01' ~liesct\vo pararnetcrs. Ilc sllo\ved formulalion but at ICitst partly t;cc:lllse the ti::tt. !'or piles ill finc \;111c\, []!c ;,clmc;lbi1ity basic parameters \vhich are used, i.c. tile driIp- i? io\v enough [idcrsiiic cfl.cct of tllc soil of on bchaviour "~LIC!LI~XII~~>ti~~~~t~ll;~t for pile!: driven .:les dri\.ins in col~esionlesssoils llas often in dc~iscsa~lii a low c!;.isin? resistance lias to be e~peitcii:I! rc:lr-i\,ir:g \\liiio for I<>oicsnlld j ,)cn reco~nizedthe use ;isof apile poteiiiial driving iormi,l;lsdi~l~c~ll~y [I:,: tlri~i~i;: t.csi franular soils ma). time. .L\s re- ;tl't~ CIICII dt~\lngscci~~e~lcc. LIcIayb of at borted [he obserFed rcsi~tnlIcc.; I,: t F- - - '+ I- * " -! '*'**-Fv~~~-e-jy;,~,. , -, ;-r,&y:, ,.* %<>+<%> -- ..,& - %,>-t.,..i ~3~&~~&~83$rT~;f. ,+Y~s~~~~.:~~+;:,~~~~-.,K?~~ +j gFtc,$i;jF:;: .... *.4r:;:,ld..:. , ,a a..;hLjX*L, A $,-.:,+."$&;,. * , &. $,><, ;, >, ,< - t3 -.''.>!,,: 0 '-,)>-, +-::,!:;;>Y?$;;-,-.,: "Lwy L, . :,;;~h:,;i2~?,;~,.:.!'t:$.>;,~$';.:+ .e>:::x>::,!,;,::.: *k.:.\. ;;;" :,... : :;4*,f .; .-,x,w. J, ,, ,, , c,,,q. 15 ~cst\pcrl'or~iiccl ;it [lie SI. Cliarlcs Rivcr l?iles \vitll an eouivalcnt din~i~r~cr- . -~ - - - . nl.. .l7 - .11. , Sitt:. tlli!; plieno~~?ciioncnu~lot he csl~lnined (30.5cni). \vas driven by tllc 7ar11c ccl~!~;) 11:; thc i~ill~~cn~.c(~fpore J>I.CSSIII.~.;IS thc s;11id II~CI~~(drop hnnimer) in n sand deposit \~l~i~i i:; so, ycr\ious ( A' -: It) cnl,:;ci.) thnr corii- \\,as pi.ol.cn to bc uniform ir: i!c nl~v~~c:il.1rlt. 1 i plctc pore p~-c\\;ui-ctlis:iip:~tion c;iri be cspcc~cci mccll;l~iical propct.lics. Therefore idc;~lc.t!~, tn occlrr \\.itIi~na I'c\\- llours: tiic incrcasc in ditior~s \i8er.c provided for an cutcnqi~.cIII bc;~i.inyc;~pacitj ~hcscfor~to bc rclatctl to yestigation of the validity of tllc usu,~lc,)11- cl~:!l!;!c occu~.iilyin tlic S~IIIL~!.!rirciii~.c ar-ound trols of qu:ili!y based on the dri~.ingencr-2: tlic pile. Thc ~13tisticalanalysis of 478 co~,;~lii:, drivin; ~.ecordshows !lint thc driving ener ;! (.'onc.Itr,ions ;IS cvalu:ifed by multi~~lvinztlie \vcieIit of liii 82 L b \'cry often in tlic pas! rhc ~alidityof t;lc liariinler 5. the d:o:, hciglit, ig very \\,ici,:i\ existing pilo dri\,inp 1'(7s171~11:1.;ii:~s been in- scattcrcd. The lii~~iisof the ranse of v;iri,~~ion 2001 I I I 1 I 4~,,!;:;,-+572y line lop I kfwm&wing ond Iating h dg \ $?;$!$--:;g?f;;!$$:: ,a 4 _.. ...rl:;4 FIG. 15. Variation of Qf wit1 time. T.\\'lCX.\S .\XI> .\l'I>Y: I.l~lIT.\TI~~SS01: l)ltI\'lX(; l~Ol I:C\\E 1111t. Sor111~11;1.J. Soil hlccli. I-ou!~ii. Div., r\.S.c'.l:.. 88 (SA1.S). the bearins capacitj coniputed hy nily of the C'['~!\!I\<;S* t\. 1'. 1010. "l))~i:~~iiic1'11~- l)~i.~ingfZol.- 2nd I=laate, Iind no useful cnrsclation to tl~e ~iit~l;l\". J. I%o..lc}n Suc. C'lvil I.ng.. 27 0). uct~~albearins capacity, tile highest ccicliicicnt C.LWV,\,OS, !\, I:. 1042. l)i>c~~<~ic~~~h',lllc hc:~rinscapacity of 3 pilc.arc better ti1;11i 01' co:i~p:~!in~i; by 3 pile driiing for11)al.l". (\Iso\, I<. i.., :111d I;L,\.\II-.k. S. !q(17, i'il: (Iriving it tIi;lt, C\..CII Finally, is sho\ill il'a iii~tllo(1 I'or~ni~I;~s'ior ft.icrinn pile.; in 5:irid. J. Soil blcch. of measuring the driving energy would be t'oui~d. Iliv., A.S.C.C., '23. (SM~). ,) PARSONS,J. D. 1966. Piling difiiculties ill the Ncw York lonnagc non renianif. Can. Geotcih. J. 7, (1) rll. nrca. J. Soil Mcch. Found. Div., A.S.C.E., 90 (SMI) 37-53. PECK,R. 13. 1942. Di%cussion to "pilc driving formulas: TAVFNAS,F. 1970. Discussion to "tests on instrunlcnl~, progress report of thc conin~ittecon thc bearing pilcs, Ogecchec River site" (>y A. S. Vcsic, J. value of pile foundations". Psoc. A.S.C.E.. 68, pp. klcch. Found. Div., A.S.C.E. 96 (SM6). 323-314. ... - 1971. Lond tcsts results on friction p~lci 11. SANDERS,J. 1851. I Tnst. SSII, p. 304. vnli~cof 11ile foundn'tions". Proc. A.S.C.C., 68 17:. SORESSEN,?'., 2nd I~ANSI:N.fl. 1957. Pilc driving formuln: 3 1 1--123. ;in investigation h:.se,t on tli~cnsiorinrtlcons~dcrnt- \\'~LI.!s~;To:I, A. hl. 1593. Piles ai?d pi!c driving. I r's,- io11 ant1 n stntisticnl alialysis. Pioc. 4th 1.C.S.Sl.F.E. ncering News Publication. Ncw York. 2, 1111. 61-65, \VIIII.AGS~<.T. 1970. The design of pilcd founda:ioli.. T~VFNAS,F., 1969. The hcaring capncity of friction pilcs Pcr~alnonP~CSS, London. in sagd-resulls of Itlacling tc.',. 7th I.C.S.M.f'.E., Y~sc;.N. C. 1970. Ilclaxntinn of piles in wntl :;I:': Spccinlty Session, No. 8, hlc~ico. inoi.pnnic silt., J. Soil Mcch. F~LIIIJ.Uiv., .4.S <..I . TA\.ISAS, F., CAPELLF,J. i-., :irld LA ROCWTLI-E,P. 96 (Sh1'7). 1970. Etudc dcs s;~blcs subii~crgks par Ccknntil-