铁路桥梁英文翻译.docx
- 文档编号:10666616
- 上传时间:2023-05-27
- 格式:DOCX
- 页数:20
- 大小:21.16KB
铁路桥梁英文翻译.docx
《铁路桥梁英文翻译.docx》由会员分享,可在线阅读,更多相关《铁路桥梁英文翻译.docx(20页珍藏版)》请在冰点文库上搜索。
铁路桥梁英文翻译
AcceptedManuscript
NotCopyedited
1
EffectofTrainLiveLoadonRailwayBridgeAbutments
M.Esmaeili1
AssistantProfessor,SchoolofRailwayEngineering,IUST,Tehran,Iran
Email:
m_esmaeili@iust.ac.ir
A.Fatollahzadeh
ResearchAssistant,SchoolofRailwayEngineering,IUST,Tehran,Iran
Email:
amir_12122@
Abstract
Assessmentoflateralexcesspressureduetotrainliveloadonthebackfillembankmentisone
ofthemainsubjectsinrailwaybridgeabutmentandretainingwalldesign.Relevantdesign
codessuchasUIC-776-1Rusuallydefineauniforminfinitesurchargeonthesurfaceof
embankmentinordertoevaluatethelaterallive-load-inducedpressureonthebridge
abutments.Thissimplifiedmethoddoesnotconsidertheactualpatternofoperationallive
loadanditsinducedpressuredistributiononthewidthandheightofthewall.Inthecurrent
study,theoperationalrailwayliveloadpatternLM71,proposedbyUIC-776-1R,wasapplied
toaccuratelycalculatethelateral-inducedpressureontheabutment.Inthisregard,the
elasticity-basedequationsofthelateral-inducedpressurecausedbyrectangularareaandstrip
loadswereutilizedtoevaluatethelateralpressuredistributionontheabutmentduetothe
railwayliveload.Forevaluatingtheresultantlateralforceandmomentonthewall,a
numericalintegrationwasconductedonthelateralpressurevaluesinthewidthandheightof
thewall.Sincethelateral-inducedpressureisrelatedtothePoisson'sratio,asensitivity
analysiswasdoneonthisparameterinordertoshowitseffectontheresultantlateralforceon
thewall.Asanapplicableresult,itwasshownthat,inthecaseofPoisson'sratioequalto0.3,
theinducedresultanthorizontalforcesonthewallswiththeheightsof1.5to7m,whichare
evaluatedusingtheuniformsurchargeofUIC,areconsiderablyunderestimatedcompared
withthevaluesobtainedinthepresentstudy.Consequently,ananalyticalequationwas
proposedforsurchargeestimationwhichledtoasaferstructuraldesignoftherailwaybridge
abutments.
Keywords:
Trainliveload,Railwaybridgeabutment,LoadpatternLM71
JournalofBridgeEngineering.SubmittedAugust9,2011;acceptedMarch7,2012;
postedaheadofprintMarch10,2012.doi:
10.1061/(ASCE)BE.1943-5592.0000393
Copyright2012bytheAmericanSocietyofCivilEngineers
Introduction
Oneoftheimportantparameterswhichshouldbetakenintoconsiderationinthedesignof
railwaybridgesisthelateralpressureontheretainingwallsandbridgeabutmentsinducedby
trainliveload.Relevantstandardsinthisregardhaveusuallyintroducedanequivalentinfinite
uniformsurchargetobeappliedontheembankmentoftheabutmentsforevaluatinglive-loadinduced
lateralpressure.UIC-776-1Rcode(2006)recommendedaninfinitelylonglayerof
earthfillwiththeconstantheightof1.7mandthesamedensityoftheembankmentfillfor
thispurpose.Assumingtheembankmentfilldensityof18KN/m3,auniformsurchargeof
30.6KN/m2shouldbeappliedontheembankmentinordertotakeintoaccounttheeffectof
trainliveloadbehindtheabutment.Thus,theIranianRailwayBridgeDesignCodeNo.139
(2000)suggestedauniformsurchargeof32KN/m2withthewidthof4mcorrespondingto
eachrailwayline.Inthismanner,thelateralearthpressurecanbecalculatedbymultiplying
thehorizontalpressurecoefficient,0K,bythementionedvalueoftheverticalsurcharge.This
simplifiedmethodnotonlydoesnotconsidertheactualpatternofoperationalliveloadandits
inducedpressuredistributiononthewidthandheightofthewallbutalsopresentsthe
underestimatedvaluesforaspecificrangeofheightsofthewall.Amongtheavailable
theoreticalworksonthepreciseevaluationoflive-load-inducedpressureontheretaining
wallsandabutments,thestudyofKim&Barker(2002)onroadbridgecouldbepointedout.
Inthisstudy,thelateral-inducedpressureduetothetruckliveloadontheroadbridge
abutmentwascalculatedusinganumericalintegrationonelasticity-basedhorizontalstresses
andtheresultwascomparedwiththevaluesrecommendedbytheAASHTO(1994).
Therefore,inthepresentstudy,thesamephilosophyandtheoperationalrailwayliveload
patternLM71proposedbyUIC-776-1Rcode(2006),wereusedtoaccuratelycalculatethe
lateral-inducedpressureontheabutment.Asfarasthedistributionofthementionedload
patternthroughtheballastlayerwasconcerned,theresultantrectangularandstriploadswere
utilizedforassessingthelateralpressure.Inthisregard,therelevantelasticity-basedequations
ofhorizontalstresseswerealsoutilizedtoevaluatethelateralpressuredistributiononthe
abutmentduetotherailwayliveload.Tocalculatetheresultantlateralforceandthemoment
onthewall,anumericalintegrationwascarriedoutonthelateralpressurevaluesacrossthe
widthandheightofthewall.Sincethelateral-inducedpressureisrelatedtothePoisson's
ratio,manysensitivityanalyseswerepreparedtoshowitseffectontheresultantlateralforce
onthewall.Astheresultofnumericalintegrations,theapplicabilityrangeoftheUICproposed
methodfortherailwaybridgeabutmentsandwallswasdeterminedbycompare
AcceptedManuscript
NotCopyedited
3
theinducedresultanthorizontalforceswiththoseobtainedfromthemethodproposedinthe
presentresearch.Consequently,ananalyticalequationwasintroducedforestimatingthe
surchargevaluesinordertosurmountthedeficienciesoftheUIC-recommendedmethod.
LiveLoadDistributionontheEmbankment
AccordingtotheUIC-776-1Rcode(2006),thetrainliveloadpatternLM71is
demonstratedbyfour250KNaxlesandtwo80KN/muniformlydistributedloads,asshown
inFig.1.
ConsideringtheLM71liveloadpattern,inordertoevaluatethelateralpressure
distributiononthewall,thisloadpatternshouldbedistributeduniformlyacrossthesleeper
andballastontherailwaysubgrade.Furthermore,thewholeconcentratedloadofLM71
patternisassumedtobeappliedtotheadjacentsleepersandtobedistributedonthetrack
subgradethroughaballastlayerwith35cmthicknessand1:
4(H:
V)distributionpattern(UIC
Leaflet774-2R(1994)).Theloadpatterndistributedonthetracksubgradelevelisillustrated
inFig.2.Accordingtotheillustratedloadpattern,thetrainmovingloadcouldbesubstituted
withfouruniformrectangularandtwoinfinitestriploads.Inthenextsection,thelateralinduced
pressureduetothesetwotypesofdistributedloadswillbediscussedinmoredetails.
CalculatingHorizontalPressureduetoTrainLiveLoad
Inthissection,followingthepreviouslypresentedrectangularandstriploads,thelateral
loadonthebridgeabutmentiscalculatedthroughthenumericalintegrationoftheintroduced
elasticity-basedhorizontalstressesinanelastichalfspace.Referringtotheequationsgivenby
Holl(1940)andPoulosandDavis(1974),theexcesshorizontalpressureduetouniformly
distributedrectangularandstriploadscanbecalculatedasfollows:
Fortherectangularareaload[Fig.3(a)]:
zC
ab
aC
zb
a
b
AC
abz
zC
pab
x
111
2
tan1(12..)tantantan
..
..
(1)
Forthestriploadperpendiculartothewall[Fig.3(b)]:
..
....
..p
x
..2
(2)
wherea,b,z,A,Cand..areshowninFig.3,..isPoisson’sratioofsoilandpis
magnitudeoftheareaload.
JournalofBridgeEngineering.SubmittedAugust9,2011;acceptedMarch7,2012;
postedaheadofprintMarch10,2012.doi:
10.1061/(ASCE)BE.1943-5592.0000393
Copyright2012bytheAmericanSocietyofCivilEngineers
AcceptedManuscript
NotCopyedited
4
ConsideringEqs.
(1)and
(2)fortherectangularareaandstriploadsandtheloadpattern
introducedinFig.2,thetotalhorizontalloadonthewallcouldbeassessedbynumerically
integratinghorizontalstressacrossthewidthanddepthofthewallandsuperpositioningthe
results.Forthispropose,thebridgeabutmentwidthbwasselectedtobe5.6mcorresponding
tothesinglelinerailwaytrackandalocalcoordinatesystemwasintroducedinorderto
simplifythenumericalintegration(asshowninFig.4).
Forapointwiththeallocatedcoordinatesofyandzalongthewalldepth,whilethefirst
rectangularloadislocatedatdistancexfromthewalledge,thehorizontalstresscouldbe
calculatedforthewallwith5.6mwidthintwodifferentstagesasfollows:
1)Theassumedpointislocatedinfrontofthewidthoftheloadedarea:
(mYm
2
2.75
2
..2.75....)
2)Theassumedpointislocatedoutsidethewidthoftheloadedarea:
(Ym
2
....2.75orYm
2
..2.75)
Theactualdistributionofhorizontalstressinthewidthanddepthofthewallcanbe
calculatedusingEqs.
(1)and
(2).Consideringtheaxialloadof250KN,theverticalpressures
oftherectangularareaandstriploadsareequalto2
1p..[250/(2.75..0.4)]..227KN/m
and2
2p..[80/2.75]..29KN/m,respectively(Fig.4b).Thefirstparameterincalculating
horizontalstressisthedistancebetweenthefirstloadandtheedgeofthewall.Itisobvious
thatthemaximumhorizontalstressoccurswhenthefirstaxleloadislocatedattheedgeofthe
wall.Foraconstantvalueofz,thehorizontalpressureatanypointinthewallcanbe
calculatedbychoosing0..Y..2.8m.Asfarastheloadsymmetrytothewallwidthis
concerned,Fig.5showsthedistributionofhorizontalstressinthehalfwidthoftheabutment
forthedepthof0.5to5.0mandseveralvaluesofPoisson’sratiobasedonthe
superpositioningoftherectangularareaandstriploadeffects.Itshouldbenotifiedthat,based
ontheclassicsoilmechanicliterature,thelogicalvaluesofPoisso
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 铁路 桥梁 英文翻译
![提示](https://static.bingdoc.com/images/bang_tan.gif)