摘 要

本桥海安县2016年农村公路危桥改造工程，为一座8m 8m 8m跨,预应力混凝土简支梁桥。简支梁桥总长35.28m.

本计算书通过计算华舍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，结合相关规范初步就理解空心板梁桥的设计思路方法，标准跨径8m 8m 8m,并排布置5块空心板；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。因此，预应力混凝土桥梁设计时，一般情况下，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，桥墩采用单排五柱式墩，直径1.2m，桥台选用桩接盖梁桥台，基础选用钻孔灌注桩，直径分别为1m和1.1m。结合上部结构荷载，桥墩立柱和桥台桩基按偏心受压计算，根据土层计算 桩长；计算内力，设置钢筋并进行校核。

关键词：张拉法；空心板梁；应力损失；钻孔灌注桩；设计计算

The Construction Drawing Design of HuaShe Bridge

ABSTRACT

This bridge is reconstruction Project of Dune Bridge in Rural Highway The whole length is 35.28m.,and the standard span of this bridge is 8m 8m 8m.

In this paper,the auther designed and calculated upper pretressed concrete hollow sslabs struture and lower struture of HuaShe bridge,ect.When calculating the upper strutur and loewer struture,combined with revelant specification and preliminary understannding of design method of hollow slabs bridge,5 pieces of hollow slabs are set up side by side.The pretressed reinforcement is use of shared steel strand, and the nominal diaemter 15.2mm.Line should keep its center ofgrevity not beyond the scope of bundle boundary.Prestressed reinforcement bends an angli combining with the change rule od shear..A pre-tension pretressed concrete form of hollow slabs struture should be designed to meet different situation under the contrrol of regulating the terms and condition, such as the bearing capacity of cracking crack width deformation and streee requirements.In these controlled conditions,the most important thing is to meet in hthe normal struture of state limits the ues of performance requrimengts and ensure that the struture is reached when the carrying capacity limit state has a safety reserve. Therefore, prestressed concrete bridge design, under normal circumatances, the first struture in accordance with the normal limit state is the use of anti-cracking cross-sevtion width of cracks or limit the normal of identified pretressed reinforced, and then from members of the of the bearing capcity limit state requirement detemine the general reinforcement. Then proceed to a lasting state of cross-ection of the carrying capacity limit state, and rhe calculation of pretressed reinforced the stress losses, ti stress the final checking, checking and cracking defirmation calculation to detemine 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. When calculating the lowed struture,the auther adopted single five-post type pier, selected the pile joint cover girder bridge and bored piles. Combining with the load of upper structure, the abutment pier column and pile foundation are calculated according to the eccentric compression, and the calculation of pile length is according to the soil. Finally, the author calculated internal force, set the steel bar and checked.After checking, the upper and lower structure of the bridge meets the requirements.

Key word: Post-tension; Hollow slabs; Stress loss; Bored piles; Design and calculati

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 1

1.5设计依据 3

2.边跨上部结构设计 4

2.1结构设计 4

2.1.1横截面布置 4

2.1.2计算截面特性 5

2.2主梁内力计算 6

2.2.1永久荷载（恒载）作用计算 6

2.2.2 可变作用计算 7

2.2.3可变作用效应计算 10

2.2.4作用效应组合 14

2.3预应力钢筋数量估算及布置 16

2.3.1 预应力钢筋截面积估算 16

2.3.2 预应力钢筋布置 17

2.3.3 普通钢筋数量的估算及布置 18

2.4换算截面几何特性计算 20

2.4.1换算截面面积 20

2.4.2换算截面重心位置 20

2.4.3换算截面惯性矩 21

2.4.4换算截面弹性抵抗矩 21

2.5承载能力极限状态计算 21

2.5.1跨中截面正截面抗弯承载力计算 21

2.5.2斜截面抗剪承载力计算 22

2.6 预应力损失计算 23

2.6.1 锚具变形、回缩引起的预应力损失 23

2.6.2 加热养护引起的温差损失 24

2.6.3 由于钢绞线应力松弛引起的预应力损失 24

2.6.4 混凝土弹性压缩引起的预应力损失 24

2.6.5 混凝土收缩、徐变引起的预应力损失 25

2.6.6跨中截面预应力损失组合 27

2.7正常使用极限状态计算 27

2.7.1 正截面抗裂性验算 27

2.7.2 斜截面抗裂性验算 28

2.8 变形验算 30

2.8.1 正常使用阶段挠度计算 30

2.8.2 预加应力引起的反拱计算及预拱度设置 30

2.9 应力验算 33

2.9.1持久状态应力计算 33

2.9.2 短暂状态应力计算 34

2.10 支座计算 36

2.10.1 选定支座的平面尺寸 36

2.10.2 确定支座厚度 37

2.10.3 验算支座的偏转 38

2.10.4验算支座抗滑稳定性 38

2.11 最小配筋率校核 39

2.12 铰缝计算 40

2.12.1 铰缝剪力计算 40

2.12.2 铰缝抗剪强度验算 42

3.下部结构设计 43

3.1 桥梁下部结构设计资料 43

3.2 桥台盖梁计算 44

3.2.1 荷载计算 44