设计说明：本次毕业设计我选择的题目是石子梁桥设计。设计结果应当满足国家现行设计规范要求，在经过仔细研读任务书介绍，综合考虑了施工难度、工程造价、美观性和环保性等多方面因素后，最终决定采用三跨混凝土预应力连续箱梁结构。箱梁的界面类型是单箱单室变高度截面。梁体使用C50混凝土，预应力钢筋采用φj15预应力钢绞线，使用自锚式拉丝锚固体系。全部箱型梁采用预制的方法进行制作，等到梁体达到设计强度后对其进行架设。本文主要介绍了该桥的设计和计算过程。首先根据任务书上相关地形、地质、水文条件等拟定3种桥梁结构主要尺寸进行方案比选，经过技术经济比较确定最佳桥型方案，然后进行上部结构设计，拟定上部结构的细部尺寸，确定施工方案，对推荐桥梁方案进行运营及施工阶段的内力计算，并进行内力组合，强度、刚度、稳定性等验算。

关键词： 公路桥梁； 预应力； 箱梁

Design of Shiziliang Bridge

Design General Description: I chose the designing of Shiziliang bridge as my graduation design. The design results should meet the requirements of the country's current design specifications, after reading the task book carefully and taking into account of the construction difficulty, project cost, aesthetics and environmental protection and other factors, the final decision is to use three - span concrete prestressed continuous box girder. Box beam interface type is single box single room and variable height section , near the fulcrum at the roof, The bottom plate and web are internally thickened to facilitate prestressed steel bars. The beam is made of C50 concrete, and the prestressed steel bar is made of φj15 prestressed steel strand. The self-anchored wire drawing and anchoring system is used. All box girders are made of prefabricated methods, so that the beam can be erectedwhen the design strength is reached. This paper mainly introduces the design and calculation process of the bridge. First of all, according to the relevant terrain, geology, hydrological conditions, etc. to prepare three kinds of bridge structure of the main dimensions of the program comparison, through the technical and economic comparison to determine the best bridge type program, and then the upper structure design, the upper structure of the detailed size, Construction plan, the recommended bridge program operation and construction phase of the internal force calculation, and internal force combination, strength, stiffness, stability and other checks.

Keywords： Highway bridge; Prestressed; Box beam

目录

1 绪论 1

2 设计资料 1

2.1 设计规范 1

2.2 设计依据 2

2.3 地质情况概述 2

2.4 相关资料 2

3 方案比选 2

3.1 构思宗旨 2

3.2 比选标准及设计原则 2

3.3 设计方案 3

3.4 方案比选 5

4 推荐方案尺寸拟定 6

5 Midas软件建立桥梁模型 7

主要材料指标 7

5.2 模型简介 8

5.3 荷载及组合说明 8

6 钢筋面积估算与钢束布置 9

6.1 预应力钢筋截面积估算 9

6.2 预应力钢筋布置 9

7 强度刚度验算 11

8 结语 43

1 绪论

钢桥比混凝土桥的出现大约早了一个世纪。虽然混凝土桥在跨径上远远不如钢桥，但是，自二战以后预应力混凝土技术逐步在全世界得到普及，使得混凝土桥梁在世界各国桥梁的总量中均占有一半以上的份额。混凝土桥梁占我国桥梁总量的百分之九十。在量大面广的混凝土桥梁建设中，人们普遍认为混凝土制备工艺简单、施工技术常规、设计方法成熟。纵观历史，可以将混凝土桥梁的技术进程大致划分为：萌芽、初创、成长、普及与发展4个阶段。

（1）1824～1875年为混凝土桥梁的萌芽阶段。这一时期主要以发明波特兰水泥（硅酸盐水泥）和建造第1座钢筋混凝土人行桥为标志。