论文总字数：55275字

摘 要

预应力混凝土连续刚构桥结合了连续梁桥和刚构式桥的受力特点，其具有结构性能优良、施工工艺简单、经济、美观并且安全等优点，现在已经成为我国大跨径桥梁的主要桥型之一。本文主要运用有限元分析软件Midas Civil和绘图软件AutoCAD进行了跨径为45m 80m 45m的高墩大跨预应力混凝土连续刚构桥设计。主要设计内容如下：

首先，根据相应的设计规范和设计原理进行了桥梁的立面与横断面设计。在进行立面设计时，确定了桥梁的分跨布置形式、梁高形式和桥梁下部结构的形式。在进行横断面设计时，决定了桥面的宽度、横断面的结构形式以及横断面的布置方式。

之后，进行预应力钢筋的估算和布置。使用有限元设计软件Midas Civil建立该桥的模型，施加规范所规定的一期恒载、二期恒载和移动荷载，运行分析得到桥梁受到的内力，根据结构设计原理进行预应力钢筋的估算，并对预应力钢筋进行布置。

然后，在有限元设计软件Midas Civil进行施工阶段分析。本次设计采用对称悬臂现浇法施工，先边跨合龙再进行中跨合龙。在Midas Civil中建立相应的施工阶段，定义好结构组、荷载组、边界组，按照设计布置好预应力钢筋，进行该高墩大跨连续刚构桥的应力核算，进行施工阶段和成桥阶段的受力分析。运用Midas Civil中的PSC设计，核算施工阶段的受力和变形、预应力受力状态、承载能力极限状态下和正常使用阶段各个截面的各项受力性能。

最后，运用绘图软件AutoCAD进行相关图纸的绘制。绘制桥梁总体布置图、箱梁一般构造图、预应力钢束布置图、桥墩一般构造图等图纸。

关键词：连续刚构桥，悬臂现浇施工，预应力钢筋，有限元分析

45m 80m 45m high pier long span continuous rigid frame bridge

21714243 Li Zhen

Supervised by Professor Wang Wenwei

Abstract

The prestressed concrete continuous rigid frame bridge combines the stress characteristics of continuous girder bridges and rigid framed bridges. It has the advantages of excellent structural performance, simple construction process, economy, aesthetics and safety, etc. It has now become a major component of long-span bridges in China. In this paper, the finite element analysis software Midas Civil and AutoCAD drawing software are used to carry out the design of the long-span prestressed concrete continuous rigid frame bridge with the span of 45m 80m 45m. The main design content is as follows:

First, the elevation and cross-section design of the bridge were carried out according to the corresponding design specifications and design principles. In the design of the facade, the form of the sub-span of the bridge, the form of the height of the bridge and the form of the structure of the lower part of the bridge are determined. In cross-section design, the width of the deck, the structure of the cross-section, and the layout of the cross-section are determined.

After that, the prestressed reinforcement is estimated and arranged. Using the finite element design software Midas Civil to establish the model of the bridge, impose a specified period of constant load, two phases of dead load and moving load, and analyze the internal forces and stresses of the bridge subjected to the operation and conduct prestressing reinforcement according to the structural design principle. Estimate and arrange the prestressed reinforcement.

Then, the construction phase analysis was performed in the finite element design software Midas Civil. Establish corresponding construction stages in Midas Civil, define structural groups, load groups, and boundary groups, and arrange prestressed steel bars according to the design, perform internal force calculation of the high-rise piers and large-span continuous rigid frame bridges, and carry out the construction phase and the completion phase. The PSC design in Midas Civil is used to design this bridge.

Finally, drawing software AutoCAD was used to draw related drawings. Draw drawings of the overall layout of the bridge, the general structure of the box girder, the prestressed beam layout, and the general structure of the pier.

KEY WORDS: continuous rigid frame bridge, Cantilever cast-in-place construction, Prestressed steel ,finite element analysis.

目 录

摘要 Ⅰ

Abstract Ⅱ

第一章 绪论 1

1.1 预应力连续刚构桥的发展现状 1

1.2 预应力连续刚构桥的特点 1

1.3 悬臂施工法简介 2

1.4 设计概述 3

第二章 立面与横断面设计 5

2.1 立面设计 5

2.1.1 桥跨布置 5

2.1.2 梁高尺寸设计 6

2.1.3 桥墩设计 6

2.2 横断面设计 8

第三章 预应力钢筋估束及布置 9

3.1 预应力钢筋估束原理 9

3.2 基于Midas Civil软件进行内力计算 13

3.2.1 模型节点及单元划分 14

3.2.2 荷载信息 14

3.2.3 边界信息 14

3.2.4 恒载内力计算 15

3.2.5 活载内力计算 20

3.2.6 毛截面特性值 22

3.3 纵向预应力钢筋估算 22

3.4 纵向预应力钢筋布置 24

第四章 建立模型 28

4.1 概述 28

4.2 施工阶段 28

4.2.1 施工阶段划分 28

4.2.2 施工流程 29

4.3 荷载 30

4.3.1 施工荷载 31

4.3.2 温度荷载 31

4.3.3 预应力荷载 31

4.4 边界条件 31

第五章 预应力损失计算 31

5.1 预应力钢束与管道之间的摩擦损失 32

5.2 锚具变形、钢筋回缩及接缝压缩损失 32

5.3 混凝土的弹性压缩带来的损失 32

5.4 预应力钢筋的应力松弛 33

5.5 混凝土收缩徐变 33

5.6 有效预应力值 34

第六章 次内力计算 37

6.1 预应力钢筋引起的次内力 37

6.2 温度荷载引起的次内力 40

6.3 收缩徐变引起的次内力 42

第七章 内力计算 47

7.1 承载能力极限状态下的作用效应组合 47

7.2 正常使用极限状态下的内力组合 49

7.3 弹性阶段截面应力计算时的内力组合 52

第八章 施工阶段分析 54

8.1 施工阶段混凝土法向压应力验算 54

8.2 施工阶段受力与变形分析 55

8.2.1 阶段2—0#块施工 55

8.2.2 阶段11—9#块施工 55

8.2.3 阶段14—边跨合龙 56

8.2.4 阶段17—中跨合龙 56

8.2.5 成桥阶段 56

第九章 成桥分析 57

9.1 受拉区钢筋拉应力验算 57

9.2 正截面抗弯验算 58

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