预应力混凝土简支T型梁桥设计解析

郑州大学毕业设计

题目：40m预应力混凝土简支T型梁桥设计

（净-7+2×0.75m人行道）

指导教师：李清富职称：教授

学生姓名：张朋杰学号：20070510235

专业：水利水电工程（道路与桥梁方向）

院（系）：水利与环境学院

完成时间：2011年6月

2011年6月1 日

摘要

本设计从最基本的设计方法入手，重点进行了主梁的设计，掌握了主梁的设计方法，其它部分的设计就可以仿照主梁设计进行。

本设计的主要内容包括：纵横断面布置，主梁设计，横隔梁设计，还有行车道板设计。纵横断面布置：根据规范要求和工程实践经验确定主梁间距与主梁片数和主梁高度及各截面主要尺寸。主梁设计：内力计算由恒载内力和活载内力计算组成。恒载内力由结构力学可求出，而活载内力计算时要利用按修正偏心压力法计算得出的荷载横向分布系数。根据计算得出的各种内力组合确定设计控制内力进而对预应力钢束数进行估算。按后张法制作主梁，采用锥型锚具和直径50mm 的抽拔橡胶管，计算各种预应力损失得出有效预应力，对主梁进行强度、应力和变形验算。横隔梁设计：设置横隔梁是为了保证各主梁共同受力和加强结构整体性，本设计中采用偏心压力法进行横隔梁计算。鉴于桥梁跨中处横隔梁受力最大，只计算跨中横隔梁内力，其余横隔梁可依据中横隔梁偏安全地选用相同的截面尺寸和配筋。行车道板设计：本设计中行车道板的受力图示为单向板。

关键词：T形梁；预应力；混凝土桥

ABSTRACT

This design begins with basic method and gives most content to the design of main beams. When the method of main beams designing is mastered, we can go on the designing of other parts.

The main content of this design is as followings: The arrange of longitudinal section and lateral section, Main beams design, Crossing beam designing and Drive-way plank designing.The arrange of longitudinal section and lateral section:According to the specification and the experience of practical engineering, we can decide the distance of girders, the number of the girders, the height of the main beams and the main size of each section.Main beams design: Internal forces include invariable force and variable force. We can use the method of the structural mechanics. To calculate the variable internal force, we calculate the lateral direction coefficient of the load with the method of corrected eccentricity pressures.with the result of the calculation, we can obtain the control internal force, and we can approximately decide the number of the pre-stressed concrete band.design the main beams with post-tensioning method, selecting pre-burry corrected tube anchoring. Then calculate the loss of the pre-stress and obtain the valid pre-stress and examine the strength, stress, and transform of the main beams.Crossing beam designing:To make sure that all main beams rear the load together and to enhance the globality of the construction, this design goes on the crossing beam calculation with the method of corrected eccentricity pressures. We only calculate the internal force of the middle crossing beam because of the maximum force is in the place of the middle of the span. Drive-way plank designing:In this design, the force diagram of the drive-way plank is single direction plank.

Key words: T-beam；pre-stress；concrete bridge.

目录

摘要 ............................................................................................................................. I ABSTRACT ................................................................................................................ II 第1章纵横截面布置 . (1)

1.1设计目的 (1)

1.2基本资料 (1)

1.3主梁间距与主梁片数 (2)

1.4主梁跨中界面尺寸拟定 (4)

1.5横截面沿跨长的变化 (5)

1.6横隔梁的设置 (5)

第2章主梁计算 (6)

2.1恒载内力计算 (6)

2.1.1 恒载集度 (6)

2.1.2 恒载内力 (7)

2.2活载内力计算（修正刚性横梁法） (7)

2.2.1 冲击系数和车道折减系数 (7)

2.2.2 计算主梁的荷载横向分部系数 (8)

2.2.3 车道荷载的取值 (12)

2.3主梁内力组合 (15)

2.4预应力钢束的估算及其布置 (15)

2.4.1 跨中截面钢束的估算和确定 (15)

2.4.2 预应力钢束布置 (17)

2.5计算主梁截面几何特性 (22)

2.5.1 净截面几何特性计算 (22)

2.5.2 换算截面几何特性计算 (22)

2.5.3 有效分布宽度内截面几何特性计算 (23)

2.5.4 各阶段截面对形心轴的静矩计算 (24)

2.6钢束预应力损失计算 (27)

2.6.1 预应力钢束与管道壁之间的摩擦损失 (27)

2.6.2 由锚具变形，钢束回缩引起的损失 (28)

2.6.3 混凝土弹性压缩引起的损失 (30)

2.6.4 由钢束应力松弛引起的损失 (31)

2.6.5 混凝土收缩和徐变引起的损失 (31)

2.6.6 预加内力计算即钢束预应力损失汇总 (34)

2.7主梁截面承载力与应力验算 (36)

2.7.1 持久状况承载能力极限状态承载力验算 (37)

2.7.2 持久状况构件的应力验算 (41)

2.7.3 短暂状况构件的应力验算 (49)

2.8主梁端部的局部承压验算 (50)

2.9主梁变形验算 (54)

2.9.1 计算由预加应力引起的跨中反拱度 (54)