论文总字数：76776字

摘 要

大井水库中桥是瓦埠湖大桥工程的一部分。瓦埠湖大桥工程位于淮南市寿县瓦埠镇，其中K10 702.0中桥跨越大井水库中闸泄水渠。现状为石拱圈实腹拱桥，年久失修，桥面、栏杆破损严重，拱脚渗水明显，坡脚浆砌片石脱落等，病害严重，承载能力不能满足现行规范要求，因此采用拆除重建方案。新桥拟采用3×18m跨径，全长54.04m。主梁为5片预应力混凝土T梁，采用先简支后连续施工工艺，预制吊装施工。桥墩为桩柱式桥墩，桥台采用双排桩轻型桥台。

本设计以大井水库中桥的工程设计总说明及交通部标准图纸为依据，对该桥进行构造设计与结构计算，然后利用Midas civil进行建模计算，与手算结果对比。上部结构采用后张法预应力混凝土T梁，此外按照规范要求对主梁的承载能力、应力、抗裂性、变形等方面进行验算。验算结果表明，大井水库中桥在现行规范的公路—Ⅰ级荷载作用下，主梁的承载能力、应力、抗裂性及变形均满足规范要求，故证明本设计方案是可行的。下部结构采用单排双柱式桥墩,对盖梁、桥墩和桩基进行内力计算和配筋后的承载力验算。

关键词：桥梁设计，预应力混凝土，T梁，先简支后连续梁桥，双柱式桥墩

ABSTRACT

The Dajing Reservoir Middle Bridge is part of the Wabu Lake Bridge project. The Wabu Lake Bridge Project is located in Wabu Town, Shouxian County, Huainan City, in which the K10 702.0 Middle Bridge spans the Dajing Reservoir Middle Gate Drainage Canal. The current situation is a stone arch ring solid belly arch bridge, which has been in disrepair for a long time, the bridge deck and the railing are seriously damaged, the water seepage of the arched foot is obvious, and the slope of the foot and the masonry stone fall off, etc., the disease is serious, and the bearing capacity cannot meet the requirements of the current regulations, so the demolition reconstruction plan is adopted. The new bridge is planned to adopt a 3×18m span with a total length of 54.04m. The main girder is 5 prestressed concrete T-beams, which are adopted a construction technology named Simple-Beam-to-Continuous and prefabricated and hoisting construction technique. The pier is a pile-type pier, and the abutment adopts a double-row pile light abutment.

he design is based on the general design description of the Dajing Reservoir Middle Bridge and the standard drawings of the Ministry of Communications. The structural design and structural calculation of the bridge are carried out, and then the modeling calculation is performed by Midas civil, which is compared with the hand calculation results. The superstructure adopts post-tensioned prestressed concrete T-beams, and in addition, according to the requirements of the specification, the bearing capacity, stress, crack resistance and deformation of the main girder are checked. The calculation results show that the bearing capacity, stress, crack resistance and deformation of the main beam of the Dajing Reservoir are all feasible under the current standard highway-I load, which proves that the design is feasible. The lower structure adopts single-row double-column piers to calculate the internal force of the cover beam, pier and pile foundation and the bearing capacity after reinforcement.

Key words: Bridge design; prestressed concrete; T girders; Simple-Beam-to-Continuous; Double-column pier

目 录

摘 要 III

ABSTRACT IV

第一章 绪论 1

1.1概述 1

1.2方案比选 1

第二章 设计基本资料 3

2.1 主要设计参数 3

2.2 主要材料 3

2.3 设计规范 3

第三章 主梁设计计算 4

3.1 主梁尺寸拟定 4

3.1.1 主梁片数与主梁间距 4

3.1.2 主梁高度 4

3.1.3 截面细部尺寸 4

3.1.4 横截面沿跨长变化 6

3.1.5 横隔梁的设置 6

3.2 毛截面几何特性计算 6

3.2.1 截面几何特性 6

3.2.2 检验截面效率指标 6

3.3 主梁作用效应计算 7

3.3.1 结构自重作用效应计算 7

3.3.2 汽车荷载作用效应计算 13

3.3.3 温差应力及基础沉降内力计算 21

3.3.4 内力组合 25

3.4 预应力钢束估算及布置 32

3.4.1 钢束估算 32

3.4.2 钢束布置 34

3.4.3 主梁净、换算截面几何特性计算 35

3.5 预应力损失及有效预应力计算 35

3.5.1 预应力损失计算 35

3.6 配束后主梁内力计算及内力组合 40

3.7 截面强度验算 43

3.8 抗裂验算 45

3.8.1 正截面抗裂验算 45

3.8.2 斜截面抗裂验算 47

3.9 持久状况构件的应力验算 50

3.9.1 正截面混凝土压应力验算 50

3.9.2 预应力钢筋应力验算 52

3.9.3 混凝土主压应力验算 52

3.10 短暂状况构件的应力验算 55

3.10.1 预加应力阶段的应力验算 55

3.11 挠度验算 56

3.11.1 汽车荷载作用下主梁边跨和中跨的最大截面挠度计算 56

3.11.2 温度效应作用下主梁边跨和中跨的最大截面挠度计算 58

3.11.3 消除结构自重后长期挠度验算 59

3.11.4 预应力引起的反拱度验算 59

第四章、下部结构设计 61

4.1设计资料 61

4.2盖梁设计计算 62

4.2.1荷载计算 62

4.2.2内力计算 66

4.2.3截面配筋设计与承载力校核 68

4.3桥墩墩柱计算 69

4.3.1荷载计算 69

4.3.2截面配筋计算及验算 71

4.4桩基设计计算 73

4.4.1荷载计算 73

4.4.2桩长计算 74

4.4.3桩的内力计算 75

4.4.4桩身截面配筋和强度验算 77

4.4.5墩顶纵向水平位移验算 78

第五章、总结分析 80

5.1结论 80

5.2建模计算对比 80

5.2.1车辆荷载 80

5.2.2温度梯度应力 81

5.3总结 82

参考文献 83

致 谢 84

第一章 绪论

1.1概述

简支转连续梁桥是近年发展起来的相较于满堂支架施工和悬臂浇筑施工的一种应用非常广泛的连续梁桥的结构形式。传统的简支梁桥在主梁间衔接处通常设为桥面连续，在移动荷载作用下很容易造成破坏和裂缝。而传统的连续梁桥在其支点处负弯矩一般会比跨中正弯矩大，考虑到经济的因素一般会设置为不等跨，中跨较长，且成本较高。而先简支后连续梁桥与传统连续梁桥相较而言，其预制梁吊装施工阶段的自重内力不会对支点产生负弯矩，对于中小跨径梁桥，其成桥阶段的支点负弯矩将大大减小，且可以设置为等跨连续梁桥，更加方便主梁的预制，刚好克服了传统连续梁桥的缺点，也可以达到连续梁桥的目的。

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