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1、本科毕业设计（论文）GRADUATION DESIGN(THESIS)论文题目： 城际铁路预应力混凝土连续箱梁设计 (48+80+48m) 本科生姓名： xxx 学号： xxx 指导教师姓名： xxx 职称： 教授 申请学位类别： 工学学士 专业： 土木工程(桥梁) 设计(论文)提交日期： xxx.6.15 答辩日期： xxx.6.17 xxx大学本科毕业设计（论文）摘 要本次设计为城际铁路预应力混凝土连续箱梁设计，跨径组成为48+80+48m。线路情况为双线，线间距为4.24.6m。主梁截面采用单箱单室直腹板形式，梁底曲线按二次抛物线变化，中支点梁高为6.4m，中跨跨中梁高为3.6m。该桥采
2、用悬臂浇筑施工方法，内力计算借助有限元软件Midas/Civil计算。拟定主梁细部尺寸后，利用Midas/Civil软件，模拟实际施工过程，计算结构自重内力、二期恒载内力、ZC活载内力及支座沉降次内力，并进行内力组合。根据梁体上下缘应力条件估算预应力钢束并进行布置。中支点截面在顶板及腹板内共布置72束，每束均采用12-S15.2钢绞线；中跨跨中截面在底板内布置34束，均采用15-S15.2钢绞线；边跨底板内布置18束，顶板内布置合龙束4束，均采用15-S15.2钢绞线。考虑钢束和混凝土收缩徐变影响，重新模拟施工阶段，进行内力计算及内力组合，以便计入预应力效应和收缩徐变效应。最后，基于新的内力组
3、合，进行正截面与斜截面抗裂性验算、正截面抗弯强度验算、斜截面抗剪强度验算、混凝土正应力与剪应力验算、预应力钢筋应力验算及挠度验算，各项验算结果均符合铁路规范要求。关键词：预应力混凝土；连续箱梁；悬臂浇筑；内力组合；截面验算- V -AbstractThis graduation project requires designing a prestressed concrete continuous box girder with span of 48+80+48m on an inter-city railway line. The line spacing of double-line ra
4、ilway through this bridge varies from 4.2m to 4.6m. Single-cell box with vertical webs is used as cross section of the girder. The variable-depth girder in a form of quadratic parabola is 6.4m deep at the main piers and 3.6m deep at the mid-span of the central span.This bridge is constructed with a
5、case-in-place cantilever method and internal forces of the girder are calculated with the finite element software Midas/Civil.After detail dimensions of the girder are given, the actual construction process is simulated with the finite element software Midas/Civil to calculate internal force of weig
6、ht of the structure, internal force of second dead load, internal force of live load of inter-city train and secondary internal force of bearing settlement. And combination of internal forces follows. According to stress condition at upper and lower edges of cross section of girder, the number of pr
7、estressing tendons is estimated and prestressing tendons are laid out in the girder. There are 72 prestressing tendons composed of 12-S15.2 steel strand placed in the top and bottom slab at the main piers; there are 34 prestressing tendons composed of 15-S15.2 steel strand placed in the bottom slab
8、at the mid-span of the central span; and there are 18 prestressing tendons and 4 closure prestressing tendons composed of 15-S15.2 steel strand placed separately in the bottom slab and in the bottom slab at the side span. Considering the influence of prestressing tendons and concrete shrinkage and c
9、reep, the actual construction process is simulated again. Then calculate internal forces of the main girder and finish combination of internal forces in order to add prestressing effect and concrete shrinkage-creep effect. Finally, based on new combination of internal forces, the following checking
10、should be finished, including normal section and oblique section crack resistance checking, normal section flexural strength checking, oblique section shear strength checking, normal stress and shear stress checking of concrete, stress checking of prestressing tendons, and deflection checking. The r
11、esult shows that each checking meets the requirement of the code for the railway bridge design.Key Words: Prestressed concrete, Continuous box girder, Cantilever pouring, Combination of internal forces, The section checking目 录摘 要IAbstractII目 录III引 言11 设计基本资料及设计特点21.1 设计基本资料21.1.1 概述21.1.2 主要技术标准21.1
12、.3 材料规格21.1.4 设计依据21.2 设计特点32 主梁细部尺寸拟定42.1 跨度42.2 梁高42.3 截面形式42.4 箱梁细部尺寸42.4.1 顶板厚度42.4.2 底板厚度42.4.3 腹板厚度52.4.4 承托52.5 横隔板63 主梁内力计算及内力组合（一）73.1 结构有限元模型建立73.2 毛截面几何特性计算73.3 恒载内力计算83.3.1 悬臂施工流程图83.3.2 结构自重内力计算83.3.3 二期恒载内力计算93.4 活载内力计算103.4.1 活载动力系数计算103.4.2 活载内力影响线及加载图示113.4.3 活载内力计算153.5 温度次内力计算163.
13、6 支座沉降次内力计算163.7 内力组合（一）174 预应力钢束设计184.1 预应力钢束估算184.1.1 估束方法184.1.2 预应力筋估算194.2 预应力钢束布置214.2.1 预应力钢束的布置原则214.2.2 纵向预应力筋布置214.2.3 横、竖向预应力筋布置234.3 配筋后实际状态下的悬臂施工过程235 预应力损失及有效应力265.1 净、换算截面几何特性265.1.1 计算原理265.1.2 净截面几何特性265.1.3 换算截面几何特性275.2 预应力损失及有效应力285.2.1 钢束与管道壁间摩擦引起的预应力损失285.2.2 锚头变形、钢筋回缩和接缝压缩引起的预
14、应力损失285.2.3 混凝土弹性压缩引起的预应力损失295.2.4 预应力钢筋的应力松弛引起的预应力损失295.2.5 混凝土收缩、徐变引起的预应力损失295.2.6 有效应力306 钢束、混凝土收缩徐变次内力计算及内力组合（二）316.1 钢束次内力计算316.2 混凝土收缩徐变次内力计算326.3 内力组合（二）337 主梁截面验算347.1 抗裂性验算357.1.1 正截面抗裂性验算357.1.2 斜截面抗裂性验算387.2 强度验算447.2.1 正截面抗弯强度验算457.2.2 斜截面抗剪强度验算497.3 应力验算537.3.1 混凝土正应力验算537.3.2 混凝土剪应力验算577.3.3 预应力钢筋应力验算577.4 挠度验算59结束语60致 谢62参考文献63xxx大学本科毕业设计（论文）引 言随着国内外梁桥的不断发展，预应力混凝土连续梁桥因其能充分发挥材料强度且受力合理，已经在中大跨径梁桥中得到广泛应用。特别是悬臂施工 工艺的问世以来，建设步伐大大加快，跨径由原来的几十米发展到现在的二百多米。另外，箱梁的截面形式能很好的承受列车的偏载作用，且动力性好，噪音小，因此，本次设计的城际铁路主梁形式采用预应力混凝土连续箱梁。本次设计的主要目的包括：(1) 通过设计中所参考的规范条例，能够加深对桥梁设计规范的理解。(2) 经过本次设计，熟练桥梁设计
