预应力混凝土连续梁桥毕业设计

摘要

本设计所设计的是预应力混凝土连续梁桥的设计，该桥位于王洼到原州区段，为单线铁路桥梁，主要设计桥梁的上部结构，设计荷载采用中—活载。

本设计采用预应力混凝土连续梁桥，其孔径布置为48+80×2+48m，全长为256m，主梁采用变高度变截面的单箱单室箱型截面，施工方法采用对称悬臂施工法。本设计使用midas 软件分析，考虑施工过程体系转换和混凝土收缩徐变因素进行恒载力计算。计算各控制截面力影响线，并按最不利情况进行加载，求得活载力包络图。定义基础沉降组，按最不利组合求得基础沉降引起的最不利力。依据规选取截面梯度温差模式，并计算温差引起的结构力。分别按主力组合和主力附加力进行荷载组合，并得到结构组合力包络图。根据各控制截面力进行了估束和配筋计算，并绘制了梁体钢束布置图。最后，对各控制截面进行了强度、抗裂性、应力和变形验算，各项检算均满足规对全预应力结构的要求。

关键词：连续梁；力计算；预应力混凝土；检算；

Abstract

What I designed at the undergraduate design is a prestressed concrete continuous beam bridge .It lies in Wangwa to Yuanzhou，Ningxia province .It is a single line railway .I mainly designed the superstructure of the bridge. The load for design is the “zhonghuo”load.

I adopt a prestressed concrete continuous beam bridge with four spans of 48+80×2+48m ，Its total span is 256m . First the size of girder is determined；highly variable for the variable beam cross-section single-Box Single girder and balanced cantilever construction is used . Then the Midas program is used to calculate the internal force caused by dead load of the first stage ，considering the construction stage ，after imposing the second stage dead load on the complete system . The internal force of the stage is calculated . The internal force influence lines of the control section is calculated ，then the live load is imposed according to the most adverse circumstances to get the Force Envelope .The program is used to determine the most adverse circumstances and calculate the internal force after defining the settlement groups of the basis.The temperature load is imposed consider the shrinkage and creep of the concrete . Then combination of load effects is made acoording to the Main force combination and the Main force plus additional force combination .According to the internal force of control sections ，the number of per-stressing steel stands is estimated and the per-stressing steel stands are arranged in the bridge . Finally a check is made of the bearing capacity ，the ability to resist crack and the sterss of the control section ，all the requirements can be met .

Keywords: Continuous beam；Internal force calculation；Prestressed concrete ；Checking computation；

目录

第一章绪论 (1)

第二章结构尺寸拟定 (2)

第一节总体布置 (2)

第二节细部尺寸拟定 (2)

一、主梁梁高 (2)

二、截面尺寸 (2)

三、各截面细部尺寸 (3)

第三节本桥主要材料 (3)

一、混凝土： (3)

二、预应力钢绞线： (3)

三、箍筋： (4)

四、应力管道： (4)

第四节施工方法 (4)

一、桥墩与零号块施工 (4)

二、悬臂施工到最大悬臂状态 (4)

三、边跨膺架现浇 (4)

四、边跨合拢 (4)

五、中跨跨中合拢 (5)

六、桥面铺装 (5)

第三章预应力混凝土连续梁桥力计算 (5)

第一节计算模型建立 (5)

第二节毛截面几何特性计算 (6)

第三节恒载力计算 (7)

一、计算方法 (7)

二、控制截面选择 (7)