外文翻译二五

唐山学院毕业设计PAGE1PAGE1Staticlateralforceprocedureforbuildings2.1DETERMINATION0FLATERALFORCES2.1.1SeismiczonefactorTheseismiczonefactorZ，giveninUBCTable16—1，istheCodeestimateoftheapplicablesitedependenteffectivepeakgroundaccelerationexpressedasafunctionofthegravityconstantg·.ThevaluesofZrangefrom0．075toO．40withtheUSAbeingdividedintosixdifferentseismiczonesinUBCFigure16—2．Thezonefactorcorrespondstogroundmotionvalueswitharecurrenceintervalof475yearswhichgivesatenpercentprobabilityofbeingexceededinariftvyearperiod．Thesevaluesarebasedonhistoricalrecordsandgeologicaldataandarealsoadjustedinordertoprovideconsistentdesigncriteriawithinlocaljurisdictions．Thezonefactorisused，inconjunctionwiththesoilprofiletype，todeterminetheappropriategroundresponsecoefficientsCaandCv。giveninUBCTables16-Qand16一R．ThesearethenusedtOprovidetheresponsespectrumenvelopeillustratedinUBCFigure16-3．2.1.2GroundresponsecoefficientsThegroundresponsecoefficientsC。andC。aredefinedinUBCSection1629．4．3andareparameterswhichreflectthepotentialamplificationofthegroundvibrationcausedbydifferentsoiltypes．ThesecoefficientsareafunctionofthezonefactorZ，thesoilprofilesSAtOSFand，whereapplicable，thenear—sourcefactorsNaandN。．ThefundamentalperiodofastructuredetermineswhichofthetwocoefficientsCaorCvgovernstheseismicdesignofthestructure．Theacceleration—basedcoefficientCacontrolsforshorterperiodsuptoapproximatelyonesecondandthevelocity—basedcoefficientC。controlsforlongerperiods．ValuesofC。andC、aregiveninTable2—1forsoilprofilestypeAtotypeE．Asite—specificgeotechnicalinvestigationisnecessarytodeterminethevalueofthecoefficientsforsoilprofiletypeF．茶2宅.钥1增.岂3克s懒o冰i悲l壶巨p垂r互o芽f谱i微l气e欲钓t架y伍p弟e柴sThegroundvibrationcausedbyanearthquaketendstobegreateronsoftsoilthanonhardsoilorrock．Asthevibrationpropagatesthroughthematerialunderlyingthestructure，itmaybeeitheramplifiedorattenuateddependingonthefundamentalperiodofthematerial．Toaccountforthispotentialamplification，sixdifferentsoiltypesareidentifiedintheCoderangingfromhardrocktosoftsoil．TheclassificationmaybemadebydeterminingonsitetheaverageshearWavevelocityinthetop100feetofmaterial．Alternatively，forsoilprofiletypesC，D，orE，theclassificationmaybemadebymeasuringthestandardpenetrationresistanceorundrainedshearstrengthofthematerial．Forrockandhardrock，theshearwavevelocitymaybeestimatedbycomparisonwithmeasurementstakenonrockofsimilarcomposition．SoilprofiletypeSBisdescribedasrockandisthatmaterialinwhichthegroundresponsecoefficientsC。andCVareidenticaltotheeffectivepeakaccelerationvalueZ．SoilprofiletypeSBOccursmainlyinthewesternstates．永S发o曲i麦l夏炮p锻r包o薪f联i劳l奔e嫂疏t惜y圣p杂e巡玩S杨A认敞i士s雹特d撞e先s征c悄r狐i律b酒e傻d川团a踪s高警h运a捞r甲d反驻r拢o欧c桐k须介a某n段d汤猛h父a壁s活秃t厉h棒e妈蜓e犯f上f早e浅c乎t捡鼻o贤f腹收r敌e咐d熄u忠c抓i夏n氏g龙涝t程h情e吼贪g帽r晶o监u芹n傲d岩牛r竹e邮s贤p团o僚n译s衰e响狗c嚼o享e针f识f渣i灵c避i抬e犹n跑t煎s证芹b历y姻播2木0阿落p催e罚r捆c拥e钳n忙t牙．墙S矿o役i狸l卫钟p卖r改o捧f图i检l冻e掘桂t推y史p蛛e轨额S却A汗乓o梯c治c绑u青r老s猾菠m绢a绪i蕉n捐l音y锣祥i治n右漂t碍h疫e性污e吼a咐s桥t倘e粱r铲n齐呜s只t勇a骑t除e悲s凡．验S眯o暴i贤l想移p碑r值o计f献i劲l罚e府住t乌y护p迷e螺望S鞋E距们i身s肝畏d掘e泊s客c征r上i贯b阔e制d示娘a扩s任饰s盆o肉f夸t墨带s嫂o微i征l闹索a暑n研d绞阵h金a伏s平尚t善h圣e淘和e碎f士f热e食c唱t孙榆o遇f编强i教n仗c关r动e训a棋s挑i斥n肺g抖引t饭h袄e暴贸v吐e木l苏o蒙c美i慰t强y响—菜b免a助s粒e意d赛迎g晃r柳o楚u画n诚d轧刺r河e胁s旗p蜂o跑n稿s苍e劝轨c园o拔e卷f涛f削i砍c利i圈e污n兰t向送C类v俩敏b抵y腿妻u巷p动怜t暂o删慕2量3便0梢台p医e传r撤c兼e扮n践t盖．柳F孝o渣r倦匀s挨o言i再l萌糠p列r滩o只f凤i圣l影e静跨t疗y熄p戴e联俯S咳F斥，弯w温h辫i抹c赏h迁案i参s荷博d封e絮s秃c拌r放i肯b揉e勿d染库a配s扶蔬s却e显n断s幅i锡t芬i拐v苍e涌描c遣l迫a邀y爱群o粘r叛定p适e证a工t刺参v涛u验l任n血e阻r丈a况b自l劈e触程t笋o壳洗p描o旦t颗e歇n煮t朝i状a嫌l丈结f将a旦i为l策u括r结e半，骑a遍梯s饭i咳t黎e帆迅s露p型e蝴c棉i命f浓i劣c鞠晴h丧a幕z勾a底r绿d羊耳e算v份a扣l环u俭a大t笛i老o祸n岛斩i婶s形拨r丰e演q餐u龟i济r躺e炕d渣舟t域o粪耽d丑e烂t素e青r迫m永i晕n塞e恩待t滥h圾e残染g券r岸o倾u诵n抢d醒耕r摸e雾s陕p知o搅n暖s棚e车炸c袖o开e挂f膛f恨i母c炭i侄e释n顽t麻s煮.产W遥h购e事n父注s情o绍i帖l湖堂p妥a冠r紧a兼m丹e职t妇e预r林s能棵a变r彻e面狡u缩n回k喷n糕o舍w裳n盯，必i带n亭胃a计c嘴c费o动r啦d奉a办n沃c滩e贵炭w谷i冷t具h红钩U蹄B罪C狸沾S遍e剂c叉t靠i雷o毕n难解1糠6肌2井9田．蔑3茂，仅s炎o似i纳l架宗p喝r礼o献f洁i谨l习e歉烫t条y摧p怖e过测S织D锈冬m欣a笛y驾住b猜e蒸享a替s乞s胁u沃m攻e夕d界育u股n勺l向e割s烟s段剂i能t译炒i法s密念d精e匹t尝e观r诱m忆i锣n珠e桶d班获t资h随a易t魄荷s规o丧i幻l犬识p轮r伐o与f衰i味l丢e但辛t共y阔p驳e鬼s肉老S歉E懂唤o怒r平叙S梳F章企m爷a映y与递b涨e踪弦p杠r笼e秃s浑e巴n熟t挠锁a汁t权朋t低h驼e庸惊s对i绵t乞e格．津T粒a起b葡l闷e渣泪2场-挣2政柳l闷i益s窃t绕s耕劝t倾h慕e协帝s盆o奇i共l填裂p炮r当o补f笋i榴l砌e瘦陈t信y戴p量e葬s盟．2.1.4SeismicsourceclassificationThemaximummomentmagnitudepotentialofafaultanditssliprateareusedtoclassifyseismicsourcetypes.FivedifferentsourcetypesareidentifiedintheCoderangingfromthemostactivetypeAsourcetotheleastactivetypeCsource.TypeCsourcesarerelatively"inactivefaults,notcapableofproducinglargemagnitudeearthquakes,andoccurmostlyoutsideCalifornia.Table2-3liststhedifferenttypesoffaults.2.1.5NearsourcefactorInregionssubjectedtolargemagnitudeearthquakes,suchasthosewhichoccurinseismiczone4,locationsclosetothefaultrupturemayexperienceagroundaccelerationuptotwicethatatadistanceof10kilometersfromthesource.Toaccountforthis,theCodeintroducestwonear-sourceamplificationfactors.TheseareNatheacceleration-basedfactorforshortperiodstructuresandNvthevelocity-basedfactorforperiodsexceedingonesecond.ThesefactorsareapplicabletoseismicsourcetypeAandseismicsourcetypeB,andhaveavalueofunityfortypeCfaultsregardlessofdistance.2.1.6FundamentalperiodEachstructurehasauniquenaturalorfundamentalperiodofvibrationwhichisthetimerequiredforonecycleoffreevibration.Thefactorsdeterminingthefundamentalperiodincludethestiffnessandheightofthestructure,andthefundamentalperiodmayvaryfrom0.1secondsforasingle-storybuildingtoseveralsecondsforamulti-storybuilding.Asafirstapproximation,thefundamentalperiodmaybeassumedequaltothenumberofstoriesdividedbyl0.2.1.11SeismicresponsecoefficientTheseismicresponsecoefficientCsgivenintheNEHRPRecommendedProvisions30,31,32isusedtorepresentthedesignelasticaccelerationresponseofastructuretotheinputgroundmotion．ThecorrespondingexpressionmaybederivedfromUBCFormula(30—4)asCs=CvI／RTwhereI=importancefactor，foraspecificoccupancycategory，fromUBCTable16-KCv=velocity—basedgroundresponsecoefficient，foraspecificseismiczoneandsoilprofile，fromUBCTable16-RR=responsemodificationfactor，foraspecificstructuralsystem，fromUBCTable16-NT=fundamentalperiodofvibration，fromUBCFormula(30—8)or(30—10)Theformofthisexpressionindicatesthattheresponsecoefficientincreasesastheimportancefactorincreasesandtheresponsemodificationfactorandnaturalperiodreduce．Thevalueoftheresponsemodificationfactorisdeterminedfromconsiderationofastructure’soverstrengthcapacitybeyondthepointatwhichtheelasticresponseofthestructureisexceeded．Thevalueoftheresponsemodificationfactoralwaysexceedsunity，whichindicatesthatallstructuresaredesignedforforceslessthanwouldbeproducedinacompletelyelasticstructure．Thisreducedforcelevelismadepossiblebytheenergyabsorptionanddissipationcapacityofthestructureatdisplacementsinexcessofinitialyield．LightlydampedstructuresconstructedofbrittlematerialsareunabletotolerateappreciabledeformationinexcessofinitialyieldandareassignedlowvaluesofR．HighlydampedstructuresconstructedofductilematerialsareassignedlargervaluesofR．Theeffectoftheimportancefactoristoincreasetheseismicresponsecoefficientby25percentforessentialfacilitiesandhazardousfacilities．Thisraisestheseismiclevelatwhichelasticresponseisexceededandtheoperationalcapacityofthestructureisimpaired．Forfundamentalperiodsinexcessofapproximatelyonesecond，theaccelerationresponseofastructureattenuatesproportionallytoitsperiodandthisisreflectedintheformoftheexpressionfortheseismicresponsecoefficient．ThemaximumvalueoftheseismicresponsecoefficientmaybederivedfromUBCFormula(30—5)asCs≤2．5C。I／RwhereCa=acceleration-basedgroundresponsecoefficient，foraspecificseismiczoneandsoilprofile，fromUBCTable16-QThisexpressioncontrolsforshorterperiodsuptoapproximatelyonesecond．Forlongerperiods，theexpressionprovidesconservativevalues．Topreventtoolowavalueoftheseismicresponsecoefficientbeingadoptedforlongperiodstructures，theminimumpermittedvalueisgivenbyUBCFormula(30-6)asCs≥0.1lCaIInseismiczone4，atlocationslessthan15kilometersfromapotentialsource，theminimumvalueisfurthermodifiedbyUBCFormula(30—7)toCs≥0．8ZNvI／RwhereZ=seismiczonefactorfromUBCTable16-IandNv=velocity—basednearsourcefactorfromUBCTable16-TExample2-2(Determinationofseismicresponsecoefficient一Athreestory，steel，moment—resistingframewiththepropertiesshowninFigure2—2,aheightof36feet，andwithadampingratiooffivepercentislocatedonasiteinzone3withanundeterminedsoilprofile．CalculatethevalueoftheseismicforcecoefficientCs．SolutionFromTable2-l，usingsoilprofiletypeSDfortheundeterminedsoilprofile，thegroundresponsecoefficientsareobtainedasCa=0.36Cv=0.54TheminimumpermittedvalueoftheseismicresponsecoefficientisgivenbyUBCFormula(30-6)asCs=0.11CaI=0.11×1.0X0.36=0.040Thevalueoftheresponsemodificationfactor，foramoment—resistingframe，isobtainedfromTable2—6asR=8.5Thenaturalperiod，usingmethodA．wasderivedinExample2—1asTA=0.51secondsTheseismicresponsecoefficientisgivenbyCs=CvI／RT=1.00×0.54／(8.5×0.511)=0.125ThemaximumvalueoftheseismicresponsecoefficientisgivenbyCs=2.5C。I／R=2.5×1.0×0.36／8.5=0.106…governsThenaturalperiod，usingmethodBandafterimposingthelimitationofUBCSection1630．2.2，wasderivedinExample2—1asTA=0.71secondsThecorrespondingseismicresponsecoefficientisgivenbyCs=CvI／RT=1.00x0.54／(8.5×0.71)=0.090…governs2．1．12SeismicdeadloadTheseismicdeadloadWasspecifiedinUBCSectionI630．1．1,isthetotaldeadloadofthestructureandthatpartoftheserviceloadwhichmaybeexpectedtobeattachedtothebuilding．Thisconsistsof●Twenty—fivepercentofthefloorliveloadforstorageandwarehouseoccupancies．●Aminimumallowanceoftenpoundspersquarefootformoveablepartitions．●Snowloadsexceedingthirtypoundspersquarefoot．whichmaybereducedbyseventy——fivepercentdependingontheroofconfigurationandanticipatedicebuildup．●Thetotalweightofpermanentequipmentandfittings．Roofandfloorliveloads，exceptasnotedabove，arenotincludedinthevalueofWastheyareconsiderednegligiblebycomparisonwiththedeadloads．Indesigningfloormembersforgravityloads，theloadingintensityspecifiedinUBCSection1606．2formoveablepartitionsistwentypoundspersquarefoot．Thisvalueallowsforlocalconcentrationsofthepartitions，whiletheoverallaveragevalueoftenpoundspersquarefootisadoptedforseismicloads．Forpermanentwallswhichareconstructedofheaviermaterials，theactualweightofthewallsshallbeused．Freshlyfallensnow，notexceedingthirtypoundspersquarefoot，haslittleeffectontheseismicloadasittendstobeshakenofftheroofintheinitialphaseofanearthquake．Howevericeandcompactedsnow，exceedingthirtypoundspersquarefoot，maybeexpectedtoadheretotheroofandcontributefullytotheseismicload．建筑静态水平力分析2.1水平力决定因素2.1.1地震带因素在UBC表16-1种给出的，地震带Z因素是估计规范的可应用场地，它取决于有效的地面加速度峰值即重力加速度g。z值的取值范围为0.075-0.40，据此美国在UBC16-2中划分为六个不同的地震区。地震区与以475年为周期的地面运动值相符合，并在50年内有10%的可能超过它。这些值是是在历史记载、地质资料的基础上确定的，并且为了在地方容许的范围内提供设计标准的做了调整。区域因素与土层特性共同决定了场地影响系数Ca、Cv，见UBC表16-Q和16-R。这些后来用做反映谱包络，见UBC16-3图解。2.1.2场地影响系数场地影响系数Ca、Cv是在UBC1629.4.3部分中定义，而且反映了由不同的土壤类型引起的地面震动参数潜在的扩大。这些系数是Z因素、土层Sa-Sf和近源因素Na、Nv的函数。建筑的基本周期决定结构Ca或Cv系数，系数Ca控制大约到一秒的短周期，系数Cv则控制较长周期。A类型土层到E类型土层的Ca和Cv的值见表2-1。对于一个场地特殊的土质调查研究是必须的，这可以决定对于土层的F系数。2.1.3土层类型由地震引起的地面震动在软土上要比在硬土或岩石上强。随着震动的传播通过底层结构的材料，它也许会增强也许会削弱，这由材料的基本周期决定。为了说明这种潜在的影响，规定中从硬土到软土定义了六种不同的土壤类型。这种分类等级可能是由场地在最深100英尺的土层中的剪切波的速度决定的。另外，对于土壤剖面类型C，D或E的分类也许是根据材料标准的抗渗力或不排水固结强度。对于岩石或坚硬的土壤，剪切波速也可通过与从相似成分的岩石测量值来估计,SB类型土壤剖面被描述为石头，SB类型是场地影响系数Ca和Cv都能有效地达到Z加速度峰值的材料。SB类型土壤大部分在西部。SA类型土壤剖面是坚硬岩石，能够有效地降低场地影响系数的20%。SA类型土壤大部分在西部。SE类型土壤别称为软土，能够有效地增加波速，基于场地影响系数Cv提升230%，SF类型土壤被描述成一种敏感的粘土或者易变形的泥土，对这种场地一个特殊的危害评价来确定场地的影响系数。当土壤的参数未知道时，与UBC1629.3一致，SD类型土壤可以估定除非SE类型土壤或SF类型土壤出现在场地中。2.1.4地震源等级最大限度瞬间潜在的震源和它的滑动率被用来划分地震源类型。规范从最活跃的A类型到最不活跃的C类型定义为五个不同的震源类型。C类型与不活跃的震源有关，不能够产生巨大的地震，大多数经常发生在加利福尼亚的外围。表2-3列出不同类型的地震。2.1.5近源因素在经常发生大型地震的区域，比如在4地震带靠近断层破裂的地方，在距离震源10千米外扩展速度能提高到两倍。为了说明这些，规范介绍了两种近源扩大因素。这些是Na加速度基础因素短周期的结构和Nv速度因素超过一秒的结构。这些因素应用于震源为A类型和B类型，和一个联合值应用于C类型的与距离无关。Na和Nv的值在表2.4中给出。2.1.6自振周期每一种建筑结构都有它固有的振动周期或自振周期，即一次自由振动所需要的时间。决定结构自振周期的因素有结构的刚度和高度。自振周期的值大约在0.1s（对单质点体系）与几秒（对多质点体系）之间，也可近似的取为建筑层数的0.1倍。2.1.11地震反应系数在NEHRP推荐的版本中给出的地震反应系数用来表明弹性设计对结构在地震运动中的加速反应.符合上述表述的公式UBC30-4,如下:其中:I:重要因素,与场地类型有关见表UBC16-K；Cv:地震反应速率系数,与地震带和地基土有关见表16-R；R:地震反应限制因素,与结构体系本身有关.见表UBC16-N；T:自震基本周期,见UBC公式(30-8)或(30-10)。以上公式表明地震反应系数随着I(重要因素)的增加,R(地震反应限制因素)和T(自震基本周期)的降低而增加。地震反应限制因素的价值是由考虑结构通过超出弹性反应的那部分承载能力所决定的。地震反应限制因素的值总是超出结构整体,这表明所有的结构都将按低于仅按弹性设计的承载力进行设计。设计承载力的减少很可能是由于建筑结构地震时发生超出最初位置的位移产生吸收和消散地震能而造成的。构成轻质阻尼结构的脆性材料不能承受超出最初位移的适当变形,因此被设定为降低了R(地震反应限制因素)的值。构成高层阻尼结