（硕士学位论文）箱形桥梁弯矩变号段抗剪性能数值分析 摘要 摘要 D622004 我国现行公路钢筋混凝土及预应力混凝土桥涵设计规范 JTG 中斜截面抗剪承载力计算公式主要适用于矩形、T形、I形等开口截面梁的弯剪 受力段，没有明确给出箱形截面梁弯矩变号段的计算公式。研究表明，箱梁弯 矩符号变化段的抗剪性能与其他梁段相比表现出较大的差异性，因而采用大型 非线性有限元软件对箱梁弯矩变号段抗剪承载力进行研究。 以某350m连续箱梁桥为研究背景，取中跨跨中到第三跨反弯点之间的梁 段为研究对象。根据国内外已有研究资料，选取影响箱梁弯矩变号段抗剪承载 力的主要影响参数：箍筋配筋率、混凝土强度、纵向普通钢筋配筋率、纵向预 应力钢筋配筋率，建立箱梁16个有限元分析模型进行全过程受力数值分析，深 入认识弯矩变号段剪切性能及破坏形态，重点揭示箱梁弯矩变号段的抗剪机理 及其随主要影响参数的变化规律。全过程受力分析为箱梁弯矩变号段抗剪承载 力影响因素分析及建立简化计算方法提供了数据依据。 根据有限元模型计算结果，详细分析了混凝土强度、配箍率、纵向受拉钢 筋配筋率分别对抗剪承载力、混凝土主压应力、箍筋应力和腹板纵向预应力钢 筋应力的影响。通过回归分析和理论推导方法，建立了箱梁弯矩变号段斜截面 抗剪承载简化计算公式，并根据我国公路混凝土桥梁可靠度水平，对该简化公 式进行修正，得到了抗剪承载力的设计计算公式。 关键词：箱形桥梁，抗剪承载力，有限元方法，弯矩变号段，数值分析，简化 公式 Abstract ABSTRACT 111eformulaofshear inCodefor of Reinforced strength DesignHighway ConcreteandPrestressedConcrete and BridgesCulverts rrGD62?2004 ismainly suitablefortheshear-momentofsmall cross-sectionbeamswith segment open T-type no sectionand definiteformulais for section，I-type rectangularsection，and given withcontra in thatthe flexure show segment boxgirdersResearches point shearing of withcontraflexureis differentfromthatof performancesegment pointquite other the nonlinearfiniteelementsoftwareisusedfor the sections，SO large studying shear of flexurein strength withcontra pointbox-girders segment Onthe ofa continuous witheach backgroundthree-span box-?girderbridge span of50 from tOthecontraflexureofthethird meters，the segmentmid-span point span is totheresearchesathomeand mainfactorsthat studiedAccording abroad,the affectthe witllconWa of flexurein strength shearing segment pointboxgirderbridges include reinforcementratioand stirrupratio，concretestrength，longitudinalregular tendonratioSixteen witlldifferent longitudinalprestressing box-girders parameters aremodeledand shearbehaviors嬲wellasthefailuremodesofthe analyzedThe modelbeamsare shearmechanismsandtheirvariationswith investigatedThe ofthe arerevealedThe databasisfor changesparameters processanalysisprovides the influentialfactors anda studyingshearingstrength analysissimplifiedcalculating methodof withcontraflexurein segment pointbox-girderbridges tOthefiniteelementcalculation influencesofthemain According results，the factors the and ratio，concrete including strengthlongitudinal stirrup prestressing tendonreinforcementratiotOthe stressof shearingstrength，principalcompressive stressand reinforcementstressare concrete，stirrup prestressed analyzed longitudinal A of of withcongaflexure formula simplifiedcalculating strength shearing segment in isestablished andtheoretical point boxgirderbridges byusingregressionanalysis to for of concrete reliabilitydesignhighway bridges，the analysisAccordingprinciple formulaismodifiedanda