摘要：桥梁是一种建筑结构，专门用来使铁路、行人、道路、管线等穿越河流、山川、低地等其它交通路线。桥梁可以根据很多体系来分类，如果按照他的受力情况来归纳的话，主要有悬索桥（也称吊桥）、梁式桥、拱桥等。本设计为45 m+70 m+45 m的三跨连续梁桥设计，主要的设计对象是有关于连续梁桥的内容。连续梁桥是一种使用率较高的结构体系。它的特点较多，从连续梁桥的长处来看，它具有变形小，结构刚度好，行车平顺舒适，伸缩缝少，抗震能力强，养护简单等特点。本文有关于桥梁的设计，一般的过程为：“预可行性”阶段、“工程许可”阶段、初步设计阶段、技术设计阶段、施工图设计阶段。在本设计中，桥梁为变截面箱梁桥，所以设计中涉及到有限元的分析，且采用的是Midas软件的试用版。整个过程为定义材料和截面，建立节点单元，将结构、单元、荷载分组，设定边界条件和荷载，选择预应力钢束和布置，以及对最后设计结果图的查看。21198
毕业论文关键词：连续梁桥；Midas软件；预应力钢束
The design of a continuous girder bridge with the main spans of (45+70+45) m
Abstract：Bridges are the building structures for railways, roads, drains, pipelines, pedestrian to cross the rivers, bays, lakes, valleys, lowlands or other transport routes. There are many types of bridges in the world. According to the classification of the force systems, bridges can be pided into girder bridges, arch bridges and suspension bridges.
The design is a continuous girder bridge with the main spans of (45+70+45) m, so the main object of the study is the continuous beam bridge. As we all know, continuous bridge is a common architecture. It contains a lot of advantages, such as little deformation, structural stiffness, comfortable driving, less joints, seismic capability, and simple maintenance.
General steps of bridge design include the "pre-feasibility" stage, "Feasibility" stage, preliminary design, technical design, and construction design. The finite element analysis is involved in the design. So the Midas software is used. The process is to define the material , the cross-section, and the establishment of the unit. Then the unit and the load are grouped. The boundary conditions and the load are setted. The selection of the prestressed steel and the outcome of the construction phase are the last stage.
KeyWords：Continuous Girder Bridge；Midas；Prestressed Steel
目 录
1 绪论 1
1.1 桥梁概述 1
1.2 梁桥 1
1.3 预应力混凝土连续梁桥概述 2
1.4 发展情况 2
1.5 桥梁设计 3
1.6 Midas有限元软件简介 4
1.7 本文设计主要内容 5
2 本桥型的总体布置及结构主要尺寸的拟定 6
2.1 材料规格 6
2.2 孔径布置 6
2.3 截面设计 7
2.4 桥面的设置 8
2.5 本章小结 9
3 计算荷载作用下的主梁内力 10
3.1 有限单元模型 10
3.2 恒载作用 11
3.2.1 结构自重 11
3.2.2 二期恒载 12
3.3 活载内力计算 13
3.4 温度变化产生的次内力 15
3.4.1 整体升温 15
3.4.2 整体降温 16
3.4.3 温度梯度 17
3.5 墩不均匀沉降产生的次内力 18 45m+70m+45m三跨连续梁桥设计+CAD图纸:http://www.751com.cn/gongcheng/lunwen_13296.html