论文总字数：33411字

摘 要

桥梁作为跨越不平顺地形的构筑物，自古以来就是交通运输的咽喉。为了适应高机动化、高流量的现代交通，拥有较高的承载能力、可适应较大跨径，同时还要满足一定的行车舒适性的桥梁在交通建设中起到了显得尤为重要。

预应力混凝土连续梁桥因为整体性能好、内力分布合理、结构刚度大、变形小、抗震性能好、行车平顺性好等特点，很好地契合了现代交通在桥梁上的要求^[1]。虽然预应力混凝土连续梁桥也有诸如在沉降与温度变化作用下，会产生较大的二次内力等缺点，因此使用范围有一定的限制，但是不可否认地，这种桥型在桥梁设计中占有很高的地位。

说明书阐述了一座四跨预应力混凝土连续梁桥的设计原理、设计方法以及设计步骤，具体包括：

（1）根据设计给出的基本条件，结合各桥型的优缺点，进行桥型的合理选择。

（2）根据初步的估算与规范要求，拟定细部尺寸。

（3）应用Midas Civil进行建模，并得出在荷载作用下成桥状态的内力图。

（4）根据内力图进行关键截面的预应力钢筋数量的估算，并布置预应力钢束。

（5）进行普通钢筋的布置，并在Midas Civil中进行PSC设计，依据规范，对在不同荷载组合下的桥梁内力进行验算。

（6）设计过程中遇到的问题案例与分析。

关键词：桥梁工程 预应力 连续梁桥 逐跨施工 Midas建模

Design and calculation demonstrations for a four-span restressed Concrete Continuous Girder Bridge

Abstract

Bridges, as structures span irregular terrain, have been the key of transportation since ancient times. In order to adapt to the large amount of motorized modern traffic, bridges which can adapt to large span and guarantee driving comfort play a significant role in traffic facility construction.

Prestressed concrete continuous girder bridges can satisfy the requirements of modern traffic on bridges very well because of their good overall performance, reasonable internal force distribution, large structural stiffness, small deformation, good seismic performance and good driving comfort. Although pre-stressed concrete continuous girder bridges also have some disadvantages, such as large secondary internal force will be generated because of settlement or temperature changing. Though they have certain drawbacks, there is no doubt that this kind of bridges occupy an important position in bridge design.

This thesis will demonstrate principles, methods and procedure of a four-span prestressed concrete continuous beam bridge design, which includes the following details.

1.The choice of bridge type is made, according to basic conditions given as well as the advantages and disadvantages of different types of bridges.

2. According to the preliminary estimation and specification requirements, the detailed dimensions are worked out.

3.Midas Civil is used to simulate the bridge design and the internal force diagram of the bridge is calculated.

4. According to the internal force diagram, the quantity of prestressing steel bars in key sections is estimated and the layout of prestressing steel bundles are designed.

5. Ordinary steel bars are laid out and PSC design is carried out in Midas Civil. Internal forces of bridges under different load combinations are checked According to the code.

6. Cases and their analyses are made.

Key Words: Bridge Engineering; prestressing force; continuous girder bridge; span-by-span construction; Midas modeling

目录

第一章 绪论 1

1.1设计依据与设计规范 1

1.1.1设计依据 1

1.1.2设计采用规范与标准 1

第二章 初步设计与建模 2

2.1 桥型与尺寸拟定 2

2.1.1桥型拟定 2

2.1.2控制截面尺寸拟定 2

2.1.3顺桥向尺寸与渐变拟定 4

2.2 Midas civil模型建立 6

2.2.1节点与单元的建立和划分 6

2.2.2材料与截面的定义 7

2.2.3边界条件的定义 7

2.2.4荷载的施加 8

2.2.5施工阶段定义 10

2.2.6纵筋及箍筋的配置 14

2.2.7内力计算 14

2.3预应力钢筋的估算与布置 15

2.3.1预应力钢筋数量的估算 15

2.3.2预应力钢筋的布置与调整 17

第三章 验算与分析 22

3.1持久状况承载能力极限状态验算结果 22

3.1.1正截面抗弯承载能力验算 22

3.1.2斜截面抗剪承载能力验算 23

3.1.3抗扭承载能力验算 23

3.2持久状况正常使用极限状态验算结果 25

3.2.1结构正截面抗裂验算 25

3.2.2结构斜截面抗裂验算 26

3.3持久状况构件应力验算结果 27

3.3.1正截面混凝土法向压应力验算 27

3.3.2正截面受拉区钢筋拉应力验算 28

3.3.3斜截面混凝土的主压应力验算 28

第四章 设计案例与案例分析 29

4.1逐跨施工中的问题与步骤改善 29

4.1.1逐跨施工的原因补充 29

4.1.2逐跨施工的步骤改善 31

4.2逐跨施工的悬臂端的长度对于成桥内力的影响 33

结论 36

附录A 37

附录B 内力计算详细结果 39

B1独立荷载作用下的内力分布 39

B1.1自重 39

B1.2移动荷载 41

B1.3温度荷载 42

B1.4温度梯度 43

B1.5混凝土收缩 44

B1.6徐变作用 45

B2荷载组合下的内力结果 46

致谢 49

参考文献 50

绪论

1.1设计依据与设计规范

1.1.1设计依据

1、汽车荷载等级公路-I级

2、桥面宽度（单向行驶）：0.5m（护栏） 12.25m（机动车道） 0.5m（护栏）=13.25m

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