预应力混凝土连续梁

摘要此次毕业设计主要是关于小跨度预应力混凝土连续梁桥上部结构的设计。预应力混凝土连续梁桥凭借其结构受力性能好、变形小、伸缩缝少、行车平顺舒适、养护工程量小、抗震能力强等优点而成为最富有竞争力的主要桥型之一。设计桥梁跨度为40m+40m+40m，桥面全宽19.75m，为分离式双幅双向车道。主梁施工采用满堂支架施工。设计过程如下：首先，进行桥梁方案比选，通过综合分析，最后确定为梁桥。第二步确定主梁主要构造及细部尺寸，它必须与桥梁的规定和施工保持一致，考虑到抗弯刚度及抗扭刚度的影响，设计采用箱形梁。其次，计算桥梁的恒载及活载，确定最大弯矩截面，通过计算确定预应力钢筋的面积，定出预应力束的数目，并布置预应力束。再次，计算预应力损失。然后，进一步进行截面强度的验算，其中包括承载能力极限状态和正常使用极限状态。在正常使用极限状态验算中包括计算截面的混凝土法向应力验算、预应力钢筋中的拉应力验算、截面的主应力计算。然后再进行桥墩与桩基础的设计及计算。关键字：预应力混凝土连续梁桥，满堂支架施工，截面强度验算山东交通学院毕业设计AbstractGraduationprojectismainlyonthree-spancontinuousprestressedconcretebeambridgestructuredesign.Continuousprestressedconcretebeambridge,withitsstructurebytheforceperformance,smalldeformation,expansionjoints,smoothandcomfortabledrivingandasmallamountofmaintenanceengineering,seismiccapabilityadvantagesandbecomethemostcompetitiveoneofthemainbridge.Thespanofthedesignbridgeis40m+40m+40m,broad19.75mbridge,dividedintofourtwo-waylanes.Themainbeamconstructionadoptsfullframingconstruction.Designprocessasfollows:First,throughcomprehensiveanalysistoelectbridgeschemecomparison,thefinaldeterminationisthebeambridge.Secondly,makesurethemaingirderstructureandthesizeofthedetails,Itmustbeconsistentwiththeprovisionsandconstructionofthebridge.Takingintoaccountthebendingstiffnessandthetorsionalstiffness,thedesignadopttheboxbeam.Thirdly,throughthecalculationofthebridgedeadloadandliveload,determinethemaximummomentsection.Determinedbycalculatingtheareaofprestressedreinforcement,then,setthenumberofprestressedbeamandlayoutprestressedtendons.Then,thecalculationoflossandthesecondprestressedforces.Then,furthercross-sectionstrengthofchecking,includingload-bearingcapacitylimitstateandnormaluseoftheextremelimit.Innormaluselimitstatecalculationincludessectionsoftheconcretecalculationmethodtostresscalculation,prestressedreinforcedthetensilestresscalculation,thesectionofthemainstresscalculation.Andthenthepierandpilefoundationdesignandcalculations.Keywords:Prestressedconcretegirderbridge,Fullframingconstruction,strengthcalculationsection3目录前言....................................................................11概况....................................................................21.1工程概况...........................................................21.1.1气候条件.....................................................21.1.2地域地质构造.................................................21.2设计资料..........................................................21.2.1设计技术标准.................................................21.2.2主要材料.....................................................21.3设计依据..........................................................31.4设计规范与技术标准................................................41.5主要工程技术指标..................................................41.6建设条件..........................................................51.6.1气象........................................................51.6.2河道........................................................51.6.3水文........................................................51.6.4航运.........................................................51.6.5工程地质....................................................51.6.6地震........................................................61.6.7建筑材料与运输条件..........................................62方案比选................................................................72.1桥型方案比选......................................................72.1.1桥梁设计原则.................................................72.1.2梁桥.........................................................72.1.3拱桥.........................................................82.1.4梁拱组合桥...................................................82.1.5斜拉桥.......................................................82.1.6结构方案选择.................................................92.1.7所选定方案的概述（预应力混凝土连续梁桥）....................102.2梁部横截面形式比选...............................................122.3桥墩方案比选.....................................................123桥梁上部结构设计与计算.................................................143.1桥梁的布置及孔径的划分............................................143.2主梁尺寸拟定......................................................143.3主梁几何性质计算.................................................15山东交通学院毕业设计3.4恒载内力计算......................................错误!未定义书签。3.4.1毛截面的面积................................................163.4.2恒载集度的计算..............................................163.4.3解算二次超静定结构..........................................173.5活载内力计算.....................................................183.5.1冲击系数的计算..............................................193.5.2活载增大系数的计算..........................................203.5.3活载作用下各截面弯矩的计算..................................213.6内力组合.........................................................333.7预应力筋的设计与布置.............................................353.8非预应力筋的设计与布置...........................................383.9主梁截面几何性质计算..............................................383.10预应力损失计算..................................................393.10.1预应力筋与孔道壁之间摩擦引起的应力损失....................393.10.2锚具变形、钢筋回缩和