摘 要

本桥为江宁区殷巷街道九竹路上的一座公路桥，跨度16m跨，桥宽18m。经过几种方案评选，最终选用结构受力性能优异、形变位移小、伸缩缝少、行车舒适无不适感、后期养护方便小、抗震性能好的先张法预应力空心板简支梁桥。本计算书通过九竹路桥预应力混凝土空心板梁等上部结构及其下部结构。进行上部结构计算时，结合相关规范初步理解空心板梁桥的设计思路方法，并排布置17块C50空心板；预应力钢筋布置，采用钢绞线，公称直径d=15.2mm，应使其重心线不超过束界范围；采用先张法预应力空心板梁构造形式，设计时应满足不同设计状况下规范规定的控制条件要求，例如承载力、抗裂性、变形及应力等要求。首先根据结构在正常使用极限状态要求正截面抗裂性或裂缝宽度限制确定预应力钢筋的数量，再由构件的承载力极限状态总要求确定普通钢筋的数量，然后进行持久状况截面承载力极限状态的计算，以及计算预应力钢筋的损失，最后进行应力验算、抗裂性验算、变形计算等，确定构件满足在承载力极限状态和正常使用极限状态下的各方面的各方面要求。进行下部结构计算时，桥台按正交计算，基础选用U形扩大基础。最后，进一步进行截面强度的验算，其中包括承载能力极限状态和正常使用极限状态。在正常使用极限状态验算中包括计算截面的混凝土法向应力验算、预应力钢筋中的拉应力验算、截面的主应力计算。

关键词：先张法；空心板梁；应力损失；设计计算

Design and construction drawing of Jiuzhu Bridge

ABSTRACT

This bridge is set at Jiangning Strinct YinxiangStreet Jiuzhu Road, and it is highway bridge.The whole width is 18m,and the span is 16m.After comparing several options, the pretensioned simply supported hollow slab beam bridge, which hasthe advantages of superior mechanical properties, small deformation displacement, less expansion joint, comfortable driving property,easy to maintain in later period, and good seismic performance, is selected as the design project. In this paper,the auther designed and calculated the upper structure and bottom structure of Jiuzhu bridge.

When calculating the upper structure and bottom struture,combined with specification and preliminary understanding of design method of hollow slabs bridge, 17 pieces of hollow slabs are set up side by side.The pretressed reinforcement is use of shared steel strand, and the nominal diameter 15.2mm.Line should keep its center ofgravity not beyond the scope of bundle boundary.A pre-tension concrete form of hollow slabs structure should be designed to meet different situation under the control of regulating the terms and condition, such as the bearing capacity of cracking crack width deformation and stress requirements.In these controlled conditions,the most important thing is to meet in the normal struture of state limits the uses of performance and ensure that the structure is reached when the carrying capacity limit state has a safety reserve. Therefore, prestressed concrete bridge design, under normal circumstances, the first structure in accordance with the normal limit state is the use of anti-cracking cross-sectional width of cracks or limit the normal of identified pretressed reinforced,and then from members of the of the bearing capacity limit state requirement determine the general reinforcement. Then proceed to a lasting state of cross-section of the carrying capacity limit state, and rhe calculation of prestressed reinforced the stress losses, ti stress the final checking, checking and cracking deformation calculation to determine the carrying capacity of components meet deformation calculation to determine the carrying capacity of components meet the limit state and the normal limit the use of the state all requirements. Finally, the checking of section strength is carried out, including the limit state of bearing capacity and the serviceability limit state. In the checking of the normal use limit state, the calculation of the concrete normal stress, the tensile stress in the prestressed reinforcement and the calculation of the main stress of the section are included in the calculation of the normal limit state.

Key words：Pre-tension;hollow slab beam; stress loss;design calculation

目 录

1. 设计资料 1

1.1任务概况 1

1.2 技术标准 1

1.3 工程地质 1

1.4 材料及施工工艺 2

1.4.1 混凝土 2

1.4.2 钢筋 2

1.4.3预应力工艺 3

1.5 设计依据 3

1.6桥梁抗震设计 4

1.7基本计算数据表 5

2. 上部结构设计 6

2.1 结构设计 6

2.1.1横截面布置 6

2.1.2 计算截面特性 8

2.2 主梁内力计算 10

2.2.1 永久荷载（恒载）作用计算 10

2.2.2 可变作用计算 12

2.3 预应力钢筋设计 24

2.3.1 预应力钢筋截面积估算 24

2.3.2 预应力钢筋布置 25

2.3.3 普通钢筋数量的估算及布置 25

2.4 换算截面几何特性计算 26

2.4.1 换算截面面积 26

2.4.2 换算截面重心位置 26

2.4.3 换算截面的惯性矩 27

2.4.4 截面抗弯模量 27

2.5 承载能力极限状态计算 27

2.5.1 跨中截面正截面抗弯承载能力计算 27

2.5.2 斜截面抗弯承载力计算 29

2.6 预应力损失计算 30

2.6.1 锚具变形、回缩引起的预应力损失 30

2.6.2 加热养护引起的温差损失 30

2.6.3 由于钢绞线应力松弛引起的预应力损失 31

2.6.4 混凝土弹性压缩引起的预应力损失 31

2.6.5 混凝土收缩、徐变引起的预应力损失 32

2.6.6 跨中截面预应力损失组合 34

2.7 正常使用极限状态计算 35

2.7.1 正截面抗裂性验算 35

2.7.2 斜截面抗裂性验算 36

2.8 变形验算 37

2.8.1 正常使用阶段挠度计算 37

2.8.2 预应力引起的反拱计算及预拱度设置 38

2.9 应力计算 39

2.9.1 短暂状态应力计算 39

2.9.2 持久状态应力计算 43

2.10 支座计算 46

2.10.1 选定支座的平面尺寸 46

2.10.2 确定支座厚度 47

2.10.3 验算支座的偏转 48

2.10.4 验算支座抗滑稳定性 49

2.11 最小配筋率校核 49

2.12 铰缝计算 51

2.12.1 铰缝剪力计算 51

2.12.2 铰缝抗剪强度计算 53