摘 要
在本设计中，根据地形图和任务书要求，依据现行公路桥梁设计规范提出了预应力混凝土连续梁桥、预应力混凝土连续刚构、拱桥三种桥型方案。按照“实用、经济、安全、美观”的桥梁设计原则，经过对各种桥型的比选最终选择70m+120m+70m的预应力混凝土连续梁桥为本次的推荐设计桥型。
本设计利用桥梁博士软件进行结构分析，根据桥梁的尺寸拟定建立桥梁基本模型，然后进行内力分析，计算配筋结果，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。
本设计主要是预应力混凝土连续梁桥的上部结构设计，设计中主要进行了桥梁总体布置及结构尺寸拟定、荷载内力计算、预应力钢束估算与布置、预应力损失及应力的验算、次内力的验算、内力组合验算、主梁截面应力验算。
最后，经过分析验算表明该设计计算方法正确，内力分布合理，符合设计任务的要求。
关键词：比选方案；连续梁桥；连续刚构；拱桥；结构分析；验算
ABSTRACT
In this design, according to the topography, project requirements and the current highway bridge design specification, pre-stressed concrete continuous girder bridge‚ pre-stressed concrete continuous rigid-frame structure‚ arch bridge three schemes are put forward. According to the ″practical, beautiful, safe, economic and convenient″ for construction of bridge design principles, after comparing the bridge of various structure, the final choice of 70m+120m+70m pre-stressed concrete continuous girder bridge design is decided as the recommendation.
This design uses the Dr. Bridge software to analyse the structure‚ according to the size of the bridge‚ the basic model establishment of bridge is settled‚ then the force analysis‚ calculation results of the reinforced‚ construction for each phase analysis and the check of sections. At the same time, the factors of the concrete shrinkage‚ Creep force times and temperature resultant times must be considered.
The design of pre-stressed concrete continuous girder bridge is mainly the upper structure design where the main layout of bridge and size of bridge structure‚ the loading calculation， pre-stressing tendons estimation and layout‚ the loss of pre-stress and stress of the bridge‚ the resultant checked‚ internal combination calculation‚ section stress calculation girder are being worked.
Finally‚ after analysing‚ it shows that the design calculation method is right‚ the distribution of the internal force is reasonable which complies with the design requirements of the task.
KEY WORDS: Selection scheme; Continuous girder bridge; Continuous rigid-frame structure; Arch bridge; Structure analysis; Checking computation
