摘 要,本设计为公路预应力连续梁桥的上部结构设计，采用的是中跨160米和两个边跨86米的桥跨布置，采用桥面为21m宽的四车道，分为双幅，设计时只考虑单幅。截面采用单箱梁变截面。梁高从中跨4m到边跨8m。
桥梁的设计是一个复杂的过程，包括很多方面的内容，但作为毕业设计不可能像实际设计那样做到面面俱到，通过本设计主要解决五个方面的问题：桥梁横截面的拟定、桥梁结构的内力计算、主梁预应力钢筋、截面应力验算、工程量计算。在设计利用桥梁结构分析软件MIDAS/CIVIL完成了结构分析，它是采用有限元分析方法。用户建立截面尺寸后，然后建立桥的基本模型，进行内力分析，根据计算结果配筋，然后进行施工各阶段分析及截面验算，同时，必须要考虑混凝土收缩、徐变次内力和温度次内力等因素的影响。最后的结果也证明了所得的数据是符合要求的。除MIDAS/CIVIL软件之外，还利用了其他如：word, Excel, AutoCAD等计算精确又高效率的软件来进行预应力损失的计算以及截面的检算关键词： 预应力；连续梁；预应力损失；结构分析 Abstract,This design is a pre-stressed concrete continuous girder bridge’s superstructure .The superstructure of the bridge consists of a 160-metres center span and two side spans of 85-metres each. The width of the bridge is 21 meters with four roadways，and the roadway are divided into two bridges,but only one bridge we design.The cross section of this bridge is a single cell box with depth varying from 4 meters to 8 meters.After all, the course of designing a bridge is very complex. We consider 5 problems here: designing of the sections of the bridge, computation of internal force of the bridge, pre-stressed steel bars in the structure，checking the computations of the sections，and computation quantity of project .In doing this project, I completed the structure analysis by MIDAS/CIVIL, which is a Bridge Structure Analysis Software. According to the cross-section size, we primarily formulate the bridge model, and then proceed to the construction phase of the analysis, according to the force for calculating distribute the number of steel. After designing the pre-stressed steel in the structure, the next work is checking the computations of the sections .In this stage, we must considering the possible effect of secondary force caused by pre-stress, concrete creep and shrinkage, and support settlement. All data of computation from the bridge is proved correct as a result.Except from MIDAS/CIVIL , many software such as word, Excel, AutoCAD etc, which are greatly precise and efficient are used to aid analysis during calculation of pre-stress loss, cross-section check, etc.Key words： pre-stressed；continuous girder；bridge pre-stress loss；bridge structure analysis software
