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摘 要

预应力混凝土梁式桥在我国桥梁建筑上占我重要的地位，在目前，对于中小跨径的永久性桥梁，无论是公路桥梁或者城市桥梁，都在尽量采用预应力混凝土梁式桥，因为这种桥梁具有就地取材，工业化施工，耐久性好，适应性强，。整体性好以及美观等多种优点。

本设计采用装配式简支T梁结构，其上部结构由主梁、横隔梁、行车道板，桥面部分和支座等组成，显然主梁是桥梁的主要承重构件。其主梁通过横梁和行车道板连接成为整体，使车辆荷载在各主梁之间有良好的横向分布。桥面部分包括桥面铺装、伸缩装置和栏杆等组成，这些构造虽然不是桥梁的主要承重构件，但它们的设计与施工直接关系到桥梁整体的功能与安全，这里在本设计中也给予了详细的说明。

本设计主要受跨中正弯矩的控制，当跨径增大时，跨中由恒载和活载产生的弯矩将急剧增加，是材料的强度大部分为结构重力所消耗，因而限制的起跨越能力，本设计采用27m标准跨径，合理地解决了这一问题。在设计中通过主梁内力计算、应力钢筋的布置、主梁截面强度与应力验算、行车道板及支座、墩台等等设计，完美地构造了一座装配式预应力混凝土简支T梁桥，所验算完全符合要求，所用方法均与新规范相对应。本设计重点突出了预应力在桥梁中的应用，这也正体现了我国桥梁的发展趋势。

关键词：预应力，简支T梁，后张法，应力验算

Abstract

The prestressed concrete beam plate bridge occupies my important status in our country bridge construction, in at present, regarding small span permanent bridge, regardless of is the highway bridge or the city bridge, all as far as possible is using the prestressed concrete beam plate bridge, because this kind of bridge has makes use of local materials, the industrialization construction, the durability is good, compatible, integrity good as well as artistic and so on many kinds of merits.

This design uses assembly type simple support T beam structure, its superstructure by the king post, septum transversum beam, the lane board, the bridge floor part and the support and so on is composed, the obvious king post is the bridge main carrier. Its king post connects into the whole through the crossbeam and the lane board, enable the vehicles load to have the good traverse between various king posts .Bridge floor part including compositions and so on flooring, expansion and contraction installment and parapet, these structures although is not the bridge main carrier, but their design and the construction relates the bridge whole directly the function and the security, here has also given the detailed explanation in this design.

This design mainly steps the sagging moment control, when the span increases, cross the bending moment which produces by the dead load and the live load the sharp growth, is the material intensity majority of consumes for the structure

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xxx：3×28m装配式预应力简支T梁

gravity, thus limits the spanning ability, this design uses the 27m standard span, has solved this problem reasonably. In the design through the king post endogenic force computation, the stress steel bar arrangement, king post section intensity and stress checking calculation, lane board and support, pillar Taiwan and so on designs, a structure assembly type prestressed concrete simple support T beam bridge, the checking calculation completely has conformed to the requirement perfectly, uses the method and the new standard corresponds. This design has highlighted the pre-stressed with emphasis in the bridge application, this has also been manifesting our country bridge trend of development.

Key word: Pre-stressed， Simple support T beam，Tensioning，Stress checking calculation

目 录

摘要??????????????????????????????????? 1 Abstract????????????????????????????????? 2 前言??????????????????????????????????? 5 第1章 桥型设计方案 ???????????????????????????6 1.1方案一：预应力钢筋混凝土简支梁（锥型锚具）????????????6 1.1.1 基本构造布置 ???????????????????????? 6 1.1.2 设计荷载 ?????????????????????????? 6

1.2方案二：钢筋混凝土箱形拱桥????????????????????7 1.2.1方案简介???????????????????????????7 1.2.2尺寸拟定???????????????????????????7 1.2.3桥面铺装及纵横坡度??????????????????????8 1.2.4施工方法???????????????????????????8 1.2.5总结?????????????????????????????8 1.3 桥型方案三：预应力混凝土连续刚构方案（比较方案）??????????8 第2章 上部结构设计 ??????????????????????????? 9 2.1 计资料及结构布置 ???????????????????????? 9 2.1.1设计资料???????????????????????????9 2.1.2横截面布置??????????????????????????9 2.1.3横截面沿跨长变化?????????????????????? 12 2.1.4横隔梁的布置???????????????????????? 13 2.2 主梁作用效应计算???????????????????????? 13

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2.2.1永久效应计算???????????????????????? 13 2.2.2可变作用效应计算?????????????????????? 15 2.2.3主梁作用效应组合?????????????????????? 25 2.3预应力钢束的估算及其位置???????????????????? 26 2.3.1跨中截面钢束的估算和确定?????????????????? 26 2.3.2预应力钢束布置??????????????????????? 27

2.4 计算主梁截面几何特征?????????????????????? 31 2.4.1 截面面积及惯矩计算????????????????????? 31 2.4.2 截面静矩计算???????????????????????? 33 2.4.3 截面几何特性汇总?????????????????????? 34 2.5 预应力损失计算????????????????????????? 34 2.5.1 预应力钢束与管道壁之间的摩擦引起的预应力损失???????? 37 2.5.2由锚具变形、钢束回缩引起的损失??????????????? 37 2.5.3 混凝土弹性收缩引起的预应力损失?????????????? 38 2.5.4 由钢束应力松弛引起的损失??????????????????39 2.5.5 混凝土收缩和徐变引起的损失?????????????????41 2.5.6 预加力计算及钢束预应力损失汇总???????????????42

2.6 主梁截面承载力与应力验算????????????????????45 2.6.1 持久状况承载能力极限状态承载力验算?????????????45 2.6.2 持久状态正常使用极限状态抗裂验算??????????????48 2.6.3 持久状态构件的应力验算???????????????????49 2.6.4 短暂状况构件的应力验算???????????????????56 2.7 主梁端部的局部承压验算?????????????????????56 2.7.1 局部承压区的截面尺寸验算??????????????????56 2.7.2 局部抗压承载力验算?????????????????????59 2.8 主梁变形验算??????????????????????????59 第3章 基础的设计??????????????????????????? 62 3.1 盖梁的计算???????????????????????????62 3.1.1荷载计算 ??????????????????????????62

3.1.2 内力计算?????????????????????????? 69

3.2 桥墩墩柱计算?????????????????????????? 70 3.2.1 荷载计算?????????????????????????? 70 3.2.2 截面配筋计算及应力验算??????????????????? 72 3.3 钻孔灌注桩计算????????????????????????? 74 3.3.1荷载计算?????????????????????????? 74

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