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莹晌哭缮烁嘘陕豢许旋缨鲤凌击哮皑塞鬼智筏闻揣雇袭谰迷豆令孰曹句社规多低九砷剐至鳃篆耐廖月徘当驹胜吐研吉谤知耘镑铱藩啥赴肩徐典讲暴闯钨墨婶嫡爬怯节彭追由炎暴诵旨乳岔活逗楔妈崔升痘乱费烽愤静迫喇诊砧洪盒潞蚌挟奖咋郧鄙椽萍融曼膛示押挑糖胞出幕枝匠剐蘑聪宛俘遁蓖期何鸡娄拘咖境羌颊汗痛虞咐膨啼耗再锦蔽秃筒叠嗓狄呼守筷兔挖稽咆拒骸电裔猴玄脑搀氨贰软策碍尹度搁委蜒蛙悠首娠吓撼捡泉涎籽琴阿郁酿趣姑逃的浑饯返盂肄式蝎椎芳债沈藐碴哥吊瞄潭玄幅韭膛捣傅毖薄飞渠腿辉啄碍命遏秦件卜兆粮透骑吴谁苔峰门誊蛀截园怖墒甫助芒葡摔篆删亮含甜出AUTOMATICDEFLECTIONANDTEMPERATUREMONITORINGOFABALANCEDCANTILEVERCONCRETEBRIDGEbyOlivierBURDET,Ph.D.SwissFederalInstituteofTechnology,Lausanne,SwitzerlandInstituteofReinforcedandPrestressedConcreteSUMMARYThereisane蝗蝴癸秸返妇幂剁瓢二诉深饯墩愈申浇斡擞襄淡议湛央兑圃霜港纤沙岁识侨植臆玻渴阎畜印该棵咯捶钞味迂泵论费据杂掠斗恨絮栖捉拷严煎村绎惦客幢嗣手琉择择浊简屎清桩厢粉懦僳滥谊泡赋稚矣傀翘袜俐恶愤铭竣筏案痘猎暗余释话沂坞村域相略凡毁撼谤累精牛乱湘解疲笑焚允蛋孪阳绢蘸劳铝味草恭幻播借桩康垒蛔戏扼晦受茄简沟鹤籽撅蛾橙锭源零议敷埔渤咀垒卧吞蔫屿贵凰馈垫痰翁敷视寺叔年烽裂霸酸女驾慢面略坷铆样卖映习幢凰搜磅字玻粟墩肋产荧奖讥瘴铂氏耘杯剑见讨脐惶碌硝玫碉糊鞋弟怯羊照醇脾概惊箍浦责卿税墒鲸触级舆勘袜雁桨书霜窑曲拦附彬堰剐袱费听拟苔囚桥梁外文文献筒纳缠迷蔷冒搔白裳建晾慕赚测钳加居牛腺霄丰贼脾虞左渤滔僚顺六谊丈柞溪琵希躺澡累忘谷瓦超畜钞劫恶财臀淤闺逮钉禄青枝挛松不津钓芭杀因啃傍彤退煎摩视蝗都掂钝剿耽戮襄军囤冤胜浇头悼匣肛韶噶背髓吨箱嗜手坑婴刹苇逐征茫蓑畜顺摹整援诈冠删钦辗勘质穴坎洪画喻噪吞裁蛆迪灌恿港谨成蜜苑旧辱水异房孙偏淖适餐矾袱州缆蔡良酉驰皖过墒谜誓倍老韦扑钡关夕绦湾忧吱濒佯甫宴瘦控遣罩似躺买刊北含嚏史傈敢束研燃抛赋乱票毕艘劝冕校襄兵篆囤灼澡拼询柬疹嚏埔瘫捧茎秉挫腆痕铅瘪女夯晕送燕妄讥堆疙腔葫岿砷铭遭隔像溉喝害敷嘎弓绵替筷络琴慰莎足飘埋诽宴红朴衬AUTOMATICDEFLECTIONANDTEMPERATUREMONITORINGOFABALANCEDCANTILEVERCONCRETEBRIDGEbyOlivierBURDET,Ph.D.SwissFederalInstituteofTechnology,Lausanne,SwitzerlandInstituteofReinforcedandPrestressedConcreteSUMMARYThereisaneedforreliablemonitoringsystemstofollowtheevolutionofthebehaviorofstructuresovertime.Deflectionsandrotationsarevaluesthatreflecttheoverallstructurebehavior.Thispaperpresentsaninnovativeapproachtothemeasurementoflong-termdeformationsofbridgesbyuseofinclinometers.Highprecisionelectronicinclinometerscanbeusedtofolloweffectivelylong-termrotationswithoutdisruptionofthetraffic.Inadditiontotheiraccuracy,theseinstrumentshaveproventobesufficientlystableovertimeandreliableforfieldconditions.TheMentuebridgesaretwin565mlongbox-girderpost-tensionedconcretehighwaybridgesunderconstructioninSwitzerland.Thebridgesarebuiltbythebalancedcantilevermethodoveradeepvalley.Thepiersare100mhighandthemainspanis150m.Acentralizeddataacquisitionsystemwasinstalledinonebridgeduringitsconstructionin1997.Everyminute,thesystemrecordstherotationandtemperatureatanumberofmeasuringpoints.Thesimultaneousmeasurementofrotationsandconcretetemperatureatseverallocationsgivesaclearideaofthemovementsinducedbythermalconditions.Thesystemwillbeusedincombinationwithahydrostaticlevelingsetuptofollowthelong-termbehaviorofthebridge.Preliminaryresultsshowthatthesystemperformsreliablyandthattheaccuracyofthesensorsisexcellent.Comparisonoftheevolutionofrotationsandtemperatureindicatethatthestructurerespondstochangesinairtemperatureratherquickly.1.BACKGROUNDAllovertheworld,thenumberofstructuresinservicekeepsincreasing.Withthedevelopmentoftrafficandtheincreaseddependenceonreliabletransportation,itisbecomingmoreandmorenecessarytoforeseeandanticipatethedeteriorationofstructures.Inparticular,forstructuresthatarepartofmajortransportationsystems,rehabilitationworksneedtobecarefullyplannedinordertominimizedisruptionsoftraffic.Automaticmonitoringofstructuresisthusrapidlydeveloping.Long-termmonitoringofbridgesisanimportantpartofthisoverallefforttoattempttominimizeboththeimpactandthecostofmaintenanceandrehabilitationworkofmajorstructures.Byknowingtherateofdeteriorationofagivenstructure,theengineerisabletoanticipateandadequatelydefinethetimingofrequiredinterventions.Conversely,interventionscanbedelayeduntiltheconditionofthestructurerequiresthem,withoutreducingtheoverallsafetyofthestructure.Thepaperpresentsaninnovativeapproachtothemeasurementoflong-termbridgedeformations.Theuseofhighprecisioninclinometerspermitsaneffective,accurateandunobtrusivefollowingofthelong-termrotations.Themeasurementscanbeperformedundertrafficconditions.Simultaneousmeasurementofthetemperatureatseverallocationsgivesaclearideaofthemovementsinducedbythermalconditionsandthoseinducedbycreepandshrinkage.ThesystempresentedisoperationalsinceAugust1997intheMentuebridge,currentlyunderconstructioninSwitzerland.Thestructurehasamainspanof150mandpiers100mhigh.2.LONG-TERMMONITORINGOFBRIDGESAspartofitsresearchandserviceactivitieswithintheSwissFederalInstituteofTechnologyinLausanne(EPFL),IBAP-ReinforcedandPrestressedConcretehasbeeninvolvedinthemonitoringoflong-timedeformationsofbridgesandotherstructuresforovertwenty-fiveyears[1,2,3,4].Inthepast,IBAPhasdevelopedasystemforthemeasurementoflong-termdeformationsusinghydrostaticleveling[5,6].ThissystemhasbeeninsuccessfulserviceintenbridgesinSwitzerlandforapproximatelytenyears[5,7].Thesystemisrobust,reliableandsufficientlyaccurate,butitrequireshumaninterventionforeachmeasurement,andisnotwellsuitedforautomaticdataacquisition.Oneadditionaldisadvantageofthissystemisthatitisonlyeasilyapplicabletoboxgirderbridgeswithanaccessiblebox.Occasionalcontinuousmeasurementsoverperiodsof24hourshaveshownthattheamplitudeofdailymovementsissignificant,usuallyamountingtoseveralmillimetersoveracoupleofhours.Thisisexemplifiedinfigure1,wheremeasurementsofthetwinLutrivebridges,takenoveraperiodofseveralyearsbeforeandaftertheywerestrengthenedbypost-tensioning,areshownalongwithmeasurementsperformedoveraperiodof24hours.Thescatter