摘要

本毕业设计主要是对预应力混凝土连续刚构上部结构进行设计。连续刚构这种桥型结构刚度好、抗震性能好、墩梁固结有利于悬臂施工，减少了大型支座的养护维修和更换。在近二十余年来，随着预应力技术的发展和悬臂施工法的应用,连续刚构桥得到了广泛的应用。

本设计桥梁为跨度（50+70+50）m的预应力混凝土连续刚构，截面形式为单箱双室箱型。桥面宽度为20m，设计荷载标准为公路I级汽车荷载。主梁采用挂篮对称悬臂施工。设计流程如下：

第一步:确定主梁的主要构造和细部尺寸；

第二步:根据悬臂施工挂篮的起吊能力对主梁进行施工节段的划分；

第三步:在Auto CAD中建立计算模型并导入桥梁博士程序中，完成建模过程；

第四步:进行施工阶段内力分析，从而估算出所需纵向预应力筋的数目；

第五步:计算预应力损失及各项次内力，并进行主要截面验算；

最后：绘制工程图及编制说明书。

关键词：预应力混凝土连续刚构桥悬臂施工桥梁博士验算

ABSTRACT

The undergraduate design is mainly about the design of superstructure of pre-stressed concrete continuous rigid frame bridge.This type of structure has many advantages, such as excellent stiffness,high capability to withstand earthquake. At the same time, the fixation between the pier and the girder is of benefit to the cantilever construction and prevents change and maintenance of large-size supports. With the development of technology of pre-stressing and application of cantilever construction, continuous rigid frame bridge has got the extensive application in past 20 years.

This design is a prestressed concrete continuous rigid frame bridge for highway with the span of 50+70+50m. The cross section is the box section with double cell and the width of the deck is 20m. The designed load standard is: highway-Ⅰ.The main girder is constructed by symmetric cantilever equilibrium. The procedure of the design is listed as follows:

Firstly:design the main structural configuration and detail dimensions.

Secondly:divide the girder into construction segments according to the raising ability of the basket.

Thirdly:the model is established in Auto CAD software and then imported into doctorbridge software. Finish the remaining establishment of the model.

Fourthly:According to the internal force of the construction analyzed by the software we can distribute the tendons of the bridge.

Fifthly: calculate the loss of pre-stressing and secondary force, and then check the main cross-section

Finally, draw the engineering design and establish the design manuals.

Keywords: pre-stressed concrete continuous rigid frame bridge；cantilever construction；Doctorbridge；checking computations