三跨预应力混凝土连续箱梁桥上部结构设计

论文总字数：86163字

摘 要

论文作者签名： 导师签名： 日期：

三跨预应力混凝土连续箱梁桥上部结构设计

21015209 肖诗舟

指导老师 姚伟发

摘 要

本次设计题目为三跨预应力混凝土连续箱梁桥上部结构设计。根据任务书给定的工程概况和设计技术标准，结合桥梁现行设计规范，笔者共提出了三种比选方案，分别是：51 85 51m的变截面预应力混凝土连续梁桥、51 85 51m的变截面预应力混凝土连续钢构桥和110 77m独塔双跨斜拉桥。围绕“安全性、适用性、经济性、美观性、环保性”的基本设计原则，分析各类桥梁受力特点，综合比较各个比选方案的优劣，最终选择51 85 51m的变截面预应力混凝土连续梁桥作为本次设计的推荐桥型。

根据推荐桥型方案，主梁采用左右行车道相互分离的双幅桥，两幅桥对称布置、独立分析、分开修建。双幅桥主梁均采用51 85 51m的桥垮布置，边跨主跨比为0.6，全长187m。全桥桥宽24.5，单幅宽位12m，双向车道间的中央分隔带取0.5m。主梁截面采用双幅式单箱单室变截面箱梁，箱梁梁高按2次抛物线形式进行变化，桥台截面梁高2.4m，桥墩支点截面梁高5m，跨中截面梁高2.4m。桥面横向设有坡度为2％的横坡，行车方向设有坡度为1.5％的纵坡，跨中标高高于两侧标高。桥墩采用柱式桥墩，桥台采用轻型桥台，桥墩、桥台与矩形承台基础连成整体，桩基础均采用钻孔灌注摩擦桩，桩径取1.5m。全桥采用挂篮悬臂浇筑施工，施工时对称浇筑，双墩齐修，实时进行高程监测，准确控制悬臂高程。两侧桥台悬臂节段采用满堂支架整体现浇施工，桥墩、桥台均采用爬模法施工。

本次桥梁设计采用Civil Midas进行单幅桥全桥上部结构的建模、荷载模拟以及最终的验算分析。采用Civil Midas内置的悬臂施工法建模助手进行主桥基础模型的建立，划分结构基本单元。在此基础上，采用PSC桥梁助手进行桥梁截面的细部修正。本次桥梁设计主要分析并计算了设计桥梁在成桥阶段或者施工阶段中承受自重、二期、预应力荷载、支座位移、汽车荷载、温度变化以及混凝土收缩徐变作用时的结构内力与变形，并根据受力和截面特性完成了预应力钢束的估算和布置，最终完成了主梁截面承载能力极限状态的强度验算、正常使用极限状态的效应限值验算以及正常使用状态的截面应力验算。

经过Civil Midas分析验算的结果表明，本次设计桥梁设计合理，考虑充分，基本符合规范规定和任务要求。

关键词：桥梁设计，预应力混凝土，连续梁桥，结构分析，Civil Midas

Superstructure Design of Three-Span Prestressed Concrete Continuous Box Girder Bridge

21015209 Shizhou Xiao

Supervised by Weifa Yao

ABSTRACT

The topic of graduation design is the superstructure design of three-span prestressed concrete box section continuous girder bridge. According to the general situation of the project and the technical standards of the design given in the task book, combined with the current design specifications of bridges, the author puts forward three schemes for comparison and selection. They are: 51 85 51m variable cross-section PC continuous beam bridge, 51 85 51m variable cross-section PC continuous steel frame bridge and 110 77m single tower double-span cable-stayed bridge. Focusing on the basic design principles of "safety, applicability, economy, beauty and environmental protection", this paper analyses the stress characteristics of various bridges, compares the advantages and disadvantages of each alternative, and finally chooses 51 85 51m variable cross-section prestressed concrete continuous girder bridge as the recommended bridge type for this design.

According to the recommended bridge type scheme, the main girders are constructed by two bridges separated by left and right lanes. The two bridges are symmetrically arranged, independently analyzed and separately constructed. The main girders of the two bridges are arranged in the form of 51 85 51m bridge collapse. The ratio of side span to main span is 0.6 and the total length is 187m. The width of the bridge is 24.5, the width of the single bridge is 12m, and the central partition zone between two-way lanes is 0.5m. The cross-section of the main girder is double-width single-box single-chamber variable cross-section box girder. The height of the box girder varies in two parabolic forms. The height of the abutment cross-section beam is 2.4m, the pier fulcrum cross-section beam is 5m, and the height of the mid-span cross-section beam is 2.4m. The bridge deck is transversely equipped with a 2% gradient, and the driving direction is equipped with a 1.5% gradient longitudinal slope. The midspan elevation is higher than the two sides elevation. The piers are of column type and the abutments are of light type. The piers, abutments and rectangular cap foundations are connected as a whole. The bored friction piles are used in the pile foundations and the diameter of the piles is 1.5m. The whole bridge is constructed by hanging basket cantilever pouring, symmetrical pouring, double piers repairing, real-time elevation monitoring and accurate control of cantilever elevation. The cantilever segments of abutments on both sides are constructed by integral cast-in-situ construction of full support, and the piers and abutments are constructed by climbing formwork method.

The results of Civil Midas analysis and checking show that the design of the bridge is reasonable, fully considered, and basically conforms to the specifications and mission requirements.

Keywords：Bridge design, pre-stressed concrete, continuous beam bridge, structural analysis, Civil Midas

目 录

第一章 绪论 8

1.1 设计基本资料 8

1.1.1 工程概况 8

1.1.2 技术标准 8

1.1.3 设计依据 8

1.1.4 相关数据 8

1.2 方案比选 9

1.2.1 比选原则 9

1.2.2 设计方案一：51 85 51m的变截面预应力混凝土连续梁桥 9

1.2.3 设计方案二：51 85 51m的变截面预应力混凝土连续钢构桥 10

1.2.4 设计方案三：110 77m独塔双跨斜拉桥 11

1.2.5 方案比选 11

1.2.6 确定方案 13

第二章 主梁结构尺寸拟定 14

2.1 桥型布置 14

2.2 桥孔布置 14

2.3 桥梁横截面 14

2.3.1 横截面形式 14

2.3.2 梁高 15

2.3.3 梁宽 15

2.3.4 顶板与底板 16

2.3.5 腹板 16

2.3.6 桥面铺装 17

2.3.7 横隔板 17

2.3.8 横截面示意图 17

2.3.9 各截面尺寸表 19

第三章 桥梁结构单元与建模分析 24

3.1 结构单元划分 24

3.1.1 模型简介 24

3.1.2 划分原则 24

3.1.3 桥梁结构单元划分 24

3.2 各单元毛截面几何特性 25

3.2.1 毛截面几何特性计算原理 25

3.2.2 毛截面几何特性计算表 26

3.3 施工节段划分 28

3.3.1 施工节段划分原则 28

3.3.2 施工阶段划分 28

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