如何在桩基设计规范中定量考虑施工检测的作用

XX大学,XX年XX月XX日

Constructioncontrolandsafetyofpilefoundations

如何在桩基设计规范中定量考虑施工检测的作用

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xx大学土木与环境工程系1HKUSTContentsIntegratedesignandconstructionqualityassuranceProposeaproceduretoinvestigatetheeffectofconstructioncontrolonthesafetyofdrivenpilesProvidetheoreticalbasistoderivefactorsusedtoconsidertheeffectofconstructioncontrolindesigncodes2HKUSTConstructioncontroltestsoranalysesManytypesofconstructioncontroltestsoranalysesareroutinelycarriedoutasameanstocopewithuncertaintiesFinalsettestsDynamictestsusingpiledrivinganalyzers(PDA)WaveequationanalyseswithmeasurementsBlowcountanddrivingenergymonitoringStaticloadingtests3HKUST4HKUSTPDAtest5HKUSTExample:aseven-stepprocessforselectingdrivingcriteria

(Belletal.2002)1

Evaluatesubsurfaceandperformstaticpilecapacityanalysis2Selectpreliminarydrivingcriterionusingwaveequationanalysis3Driveprobe(orindicator)pilesacrossthesiteareaanduseaPDAtoevaluatecapacity,drivingstresses,andhammerperformance,includingre-tappingofselectedpilesafterinitialset-up4EvaluateandadjustthedrivingcriterionbasedontheresultsofthePDA5

Drivestatictestpile(s)usingthereviseddrivingcriterion6

Loadtestthetestpile(s)7Performafinalevaluationofthedrivingcriterionfortheproductionpilesbasedonthestaticloadingtestresults6HKUSTAllowablestressdesign(ASD)GeotechnicalresistanceDeformationRn=Nominalresistance(nominalultimatebearingcapacity)FS=FactorofsafetyQi=Nominalloadeffectdi=Estimateddisplacementunderthenominalserviceloadeffectdn=Tolerabledisplacement

7HKUSTFactorofsafetyAfactortocompensateforalluncertaintiesindesign,notsimplyafactorofstrengthreserve.Allfoundationmayfail!Theproblemishowlikely.FOSdependson:

RequiredreliabilityConsequencesoffailureUncertaintiesinsoilpropertiesandappliedloads

LevelofconstructioncontrolCost-benefitconsiderations8HKUSTFactorofsafetyandlevelofconstructioncontrol(basedonLikins,2004)9HKUSTLimitstates

Alimitstateisaconditionbeyondwhichastructuralcomponentceasestofulfillthefunctionforwhichitisdesigned(Withiametal1997).Strengthlimitstates(ultimatelimitstates)GeotechnicalresistanceStructuralresistanceServicelimitstates(functionofstructureunderexpectedserviceloads)Deformations,vibration,cracking,localdamage,deterioration(durability)10HKUSTSomeultimatelimitstatesforfoundations11HKUSTProbabilitydensityfunctionfQ,fRQ,R_Q_RAreaprobabilityoffailureLoadeffectQResistanceRProbabilityoffailure,pf

=P(R<Q)ConceptofreliabilitybaseddesignMeanFS=/NominalFS=Rn/Sn_R_QQnRn12HKUSTLimitstatedesignUltimatelimitstates(MOC2002)Tobecheckedindesignofalltypesofstructures&loadcombinationsServiceabilitylimitstatesTobecheckedonlyforimportantordifficultfoundations

13HKUSTGeotechnicalresistance:

Servicelimitstate:

(sameasASD)

Rn=Nominalresistancef=Resistancefactor,asafunctionoflevelofconstructioncontrolQi=Loadeffect

gi=Loadfactor,definedinsuperstructuredesign=Factortoaccountforeffectsofductility,redundancyandoperationalimportance,>0.95di=Estimateddisplacementunderthenominalloadeffect(ServiceIloadcombination,gD=gL=1.0)dn=TolerabledisplacementLoadandresistancefactordesign(AASHTO)14HKUSTTargetreliabilityindex(MOC2001)

UltimatelimitstatesFailuretypeGeotechnicalcategoryCategoryICategoryIICategoryIIIDuctilefailureBrittlefailure

ServiceabilitylimitstatesbT=0ifthedisplacements,cracks,localdamagesetc. causedbyloadeffectsarereversibleafterthe loadeffectsareremoved.bT=1.5iftheseserviceabilityindicatorsareirreversible aftertheloadeffectsareremoved.15HKUSTResistancefactorsforgeotechnicalstrengthlimitstateofaxiallyloadedsinglepiles(fromAASHTO1998)16HKUSTValuesoflvforvariousmethodsofpileconstructioncontrol(fromAASHTO1998)17HKUSTReliabilitymethodtoconsidereffectofconstructioncontrolEstimateempiricalstatisticsofadesignmethodReducethevariabilityofthedesignmethodgiventheoutcomeofacontroltestoraseriesofcontroltestsObtainnewstatisticsofthedesignmethodObtainnewpartialfactors/resistancefactorstoachievetargetreliability18HKUSTUncertaintyofdesignmethods19HKUSTBiasfactorandcoefficientofvariationforvariousdesignmethods*Note:20HKUSTWhat赚hap轮pens厘if餐test宵pil桐esp忧ass册cont践rol副test纪s?–床Bay锁esia伴nre木gres悼sion笛ana舍lysi冤sx=m售eas税ure糊dp鲁ile尾ca物pac裹ity捎/pr壳edi末cte矩dp阿ile斤ca膨pac挪ityxfol最low歪sa锡lo宣gno惕rma礼ld勉ist鉴rib登uti桂onEmpi辰rica凭lst衣atis狭tica聋lva真lues鄙ofxmeanmsta仁nda挣rd抛dev管iat累ionsTake灰the眼mea阁nmas撤av书ari翁abl处eAp件ile双pa族sse驻sncon捆sec溪uti桌ve安con滤str恭uct凑ion矮te吴sts袍atx=xT,t通hen饼th外ep驾rob麦abi秘lit算yt谣hat汉al雁lo垮ft胀hentes辩tp牺ile售sd宿on烧ot嘉fai谈la影txTis(蹦Zhan拣g,2工004)娃isThe寇di今str侧ibu纱tio畏no菜fxist忠hen具upda塌tedUpd漂ate亮ds般tat嘉ist染ics怠fo锻rx:l携arg粒ermand斩smal案lers21HKUS谅TExa于mpl立e:告Des万ign常ba如sed连on高a裁SPT夹me奔tho洗d(为Mey息erh绘of内197底6)姨and蜘ve壳rif僚ied类by扣pr雄oof课te仆sts结at拌tw桥ice非th楚ed高esi怕gn槽loa炭dlR=1个.30COVR=0.半5022HKU恰STExam灰ple:Upd献ate贪db蛾ias呀fa辅cto漏ra啊nd雄coe念ffi全cie税nt廉of赞var街iat右ion逗as以fu歪nct纯ion年of就pi纳le勒cap荷aci鄙ty23HKUS拳TCal悠cul绍ati汗ng筒res共ist孤anc惹ef镰act嫩or恳bas倍ed沿on弓upd裳ate骂dp被ile哀ca凶pac煤ity笛st邀ati男sti术csCOVR,CO叙VQD,a土nd设COVQL=c族oef汤fic邪ien矿ts纺of兄var丢iat港ion疫of牌re淡sis哲tan桃ce托R,厨dea绞dl宇oad骑QD,an尿dli巴vel蕉oad雅QL,re刷spec酸tive贱ly;lR,lQD,a特ndlQL=bi服asf张acto效rso蜜fre尤sist授ance途,de少adl凡oad,镜and王liv许elo刮ad,梨resp华ecti直vely恼;Dand睡L=lo燥adf度acto捧rsf逼ord暴ead税load满and意liv销elo附ad,貌resp吴ecti里vely柔;bT=ta堆rget挡rel信iabi限lity萄ind望ex24HKU杏STEff滋ect杀of丘co杏nst新ruc锦tio岩nc苏ont钉rol墨on译sa蜓fet率yf谱act器orReq角uir派ed榴fac技tor奏of腐sa返fet澡ya家fte俱rv胖eri叶fic役ati赔on阿by效dif狼fer嗓ent啊le洞vel浊so筛fc肃ons它tru伞cti组on和con滩tro园la介tbT=2刚.025HKUS右TReq桨uir牛ed绘fac控tor欠of门sa拘fet歇ya渡fte拐rv勾eri软fic滋ati泽on娘by慰dif阀fer凑ent跌le平vel掀so庆fc本ons支tru胆cti笋on躺con询tro明la彼tbT=2.贿5Eff静ect浴of弄co域nst酬ruc臣tio叫nc拉ont在rol刚on结sa娇fet巾yf绣act膀or26HKU弃STThe陈requ鸭ired幼FS姥can拆bes犹ubst结anti坏ally份red足uced护thr棵ough墓car热eful味con湿stru芽ctio梯nco挠ntro完l.T掉her血equi戏red掠FSc凭anb夫ere河duce广dfr励om3碧.50晨for贩the租stat买ica剧naly热sis忆meth匆odb自ased虑on钢the盲SPT辰to1电.42办atbT=2.获0,a顺ndt劝o1.揉80a录tbT=2幕.5赛for荷th弦es势ame御an疯aly迷sis盼th候at庆is放ver但ifi北ed顶wit慈ht傅wo俘CAP烫WAP迫an搁aly学ses端pl展us铺two改st奶ati倡cl针oad枪ing乖te装sts蕉.The页re跳qui食red燃FS锅de届cre区ase赶sw费ith嚷th润el答eve赤lo释fc孕ons近tru裂cti琴on左con娱tro精l.制For炒in亦sta刺nce既,u浊sin栽gt蠢he俊SPT粱me努tho旋d,寻the瞒re栽qui俭red稳FS锐st眠or域eac取hbT=2.足5ar相e2.坛24,浴2.03填and开1.8袄0,r移espe蒸ctiv罢ely爆afte地rve扶rifi淘cati港onb察ytw罪oPD宏Ate忠sts,震two蒙sta征tic旗load终ing描test荡s,a较ndt壶woP浅DAt绳ests喜plu缎stw遵ost壳atic板loa肯ding写tes昆ts.The愉requ茧ired困FSs片for背dif善fere抬ntd斧esig境nme琴thod获sto麦rea久cht虚her甚equi辟red粮targ亡etr懂elia揪bili陈tya瞒red杜iffe规rent游bec鸭ause寺eac滴hme昆thod道is利asso遍ciat蚀edw行ith攀diff械eren嫁tbi趣asa蜜ndC消OV.胞Thus早it幻玉isn炊otr腊easo夹nabl估eto副spe昏cify唯the展sam伍eFS迁for木dif胳fere辞ntd坟esig疑nme纤thod碎sif唱the服sed厅esig电nme狭thod商sar萄eno谢tsu距ffic窑ient蠢lyv鞋erif可ied拢byc身ontr件olt腹esti蛮ng.Afte电rve相rifi贝edb呜ysu轿ffic搞ient弊con荐stru哈ctio单nco如ntro贵lte呆stin哈g,t阵her贱equi遵red垫FSs偷for幕diff劲eren骗tde故sign物met么hods猴are片not绕sen助siti蜡vet歌oth胀eac议cura脊cyo冈fth航ein鬼divi繁dual暴met晶hods呢.Fo沙rex壶ampl目e,t溉her琴equi墓red嫁FSs延for约the神five料des添ign蛋meth扣ods杆afte寸rve祥rifi否cati趋onb筋ytw帖oPD形Ate绑sts咳plus税two刮sta贼tic挪load赶ing缴test辩sfa拜lli蜻nto俭narr开owr岛ange侧s1.烂44-1吵.55摩and有1.80闹-1.8手8.27HKU房诚STEff范ect佣of吊co尘nst刊ruc射tio词nc弟ont毁rol怠on览re沟sis胖tan荐ce香fac天torRequ呢ired挽res畏ista撑nce讨fact此ora扎fter户ver道ific咱atio朽nby贿dif抽fere铲ntl见evel成sof蒸con堆stru目ctio蝴nco屠ntro芝latbT=2.浸528HKU沉STThe欠re扩qui德redfincr晶ease东swi栽tht哥hel驶evel伴of为cons只truc彩tion秘con跨trol行.Fo鉴rth蒜ede壁sign挖bas举edo纪nth妥eSP图Tme绕thod衰,th限ere嫂quir琴edfafte惜rve仿rifi俭cati拔onb仆ytw脾oPD尖Ate误sts嫌only师,tw跟ost调atic蠢loa哗ding诉tes验tso袖nly,杜and每two隶PDA慢tes虾tsp补lus披two参stat敲icl归oadi罢ngt息ests硬are设0.6嫂1,0公.69,累and午0.7殿5,r采espe酒ctiv舌ely.Afte拳rsa竹tisf斑ying气suf坛fici绸ent从cons开truc请tion美con川trol盆tes叔tso勒ran肾alys氏es,毫the彩requ咽iredfvalu漆esf浑ort渗hef愚ive等desi绍gnm性etho耐dsa斥ren裙ots个ensi霜tive镰to严the墓accu铃racy羽of关the茄indi晚vidu犁alm抢etho季ds.爸For离inst克ance驳,af逃ter舰veri乎fica莲tion梳by途two奇PDA遣test舰spl忍ust甚wos凡tati粘clo克adin独gte仍sts,湿the枣req饥uire体dfval拳ues义fo擦rt泪hes怖ed胜esi神gn狸met幸hod萍sf租all值in乞to仿an屑arr裕ow笔ran息ge卫0.7论2-0欺.75岩.29HKUS袖TVal腾ues荷oflvafte鹊rve扑rifi回cati阵onb件ydi迟ffer爱ent艳leve贯lso粪fco迫nstr及ucti拖onc禾ontr筝ola爽tbT=2.狡5Note宫:Ta馆ket校hose房诚wit叫hCA悔PWAP库+Loa鞭dte钢sta奶s1.健0030HKU猛STReq题uir牲ed里fac塑tor席of扭sa斧fet厉ya预fte覆rv个eri筋fic枣ati喷on绕by魔dif怪fer栋ent喷co严nst犯ruc涂tio车nc娘ont粉rol旅me虚asu责res31HKU婆STAse很xpec进ted,血the翁req巴uire永dFS援dec京reas址esw责ith性the微numb扭ero祸fco孩ntro旦lte视sts捆ora卧naly爹ses,膀par兰ticu剥larl当yby亡the财fir拆stf秩ewt指ests邻or就anal叮yses更.Aft怒er打sat艺isf锈yin野ga姑su漆ffi拒cie笛nt篇num蛇ber春of另co耳ntr严ol降tes换ts何or埋ana仔lys悉es,降th他er任equ才ire涛dF狗Sv估alu稀es围for绪al蝇lt汗he泄fiv必ed枪esi狠gn拒met叠hod彼sa嫂ppe趟ar极to激be联sim数ila赶r.纱Thi煎si自ndi殿cat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