波形钢腹板刚构桥和普通PC刚构桥跨中下挠对比分析

Comparative Analysis of Midspan Deflection of Corrugated Steel Webs Rigid Frame Bridge and PC Rigid Frame Bridge

为对比研究波形钢腹板刚构桥和普通PC刚构桥的下挠特性,分别建立某大跨波形钢腹板刚构桥的杆件模型及三维实体模型,在此基础上将钢腹板替换为混凝土腹板,并添加腹板预应力束,对比研究钢腹板剪切、混凝土收缩徐变、预应力损失等因素对两桥的影响。结果表明:自重作用下钢腹板相比混凝土腹板产生了较大的剪切变形,波形钢腹板刚构桥挠度更大;预应力主要产生轴向力而非竖向力,故预应力作用下两种桥梁产生的剪切变形均不明显;相对湿度和收缩徐变的改变对普通PC刚构桥挠度影响更明显;普通PC刚构桥成桥各阶段总竖向位移约为波形钢腹板刚构桥的1.6-2.0倍。体内预应力损失对波形钢腹板刚构桥和普通PC刚构桥均有较明显的影响,体外预应力损失对波形钢腹板刚构桥挠度影响不明显;自重系数每增加0.025时,两桥跨中挠度约增加6%-8%。

In order to study the deflection characteristics of corrugated steel webs rigid frame bridges and PC rigid frame bridges, the midas Civil model and FEA model of a long-span corrugated steel webs rigid frame bridge were established respectively. Then the steel webs were replaced by concrete webs, and web prestressing tendons were added. The effects of steel webs shear, concrete shrinkage and creep, prestressing loss and other factors which effect the deflection were studied comparatively. The results show that the deformation of steel web caused by shearing is larger than concrete webs under dead weight;The shearing deformation of the two bridges under prestressing is not obvious;The change of relative humidity and shrinkage creep make obvious influence on PC rigid frame bridges;The total vertical displacement of each stage of the PC bridge is about 1.6-2.0 times of the other one. The internal prestressing loss make obvious influence on the deflection while the external prestressing loss does not. The mid-span deflection of the two bridges increases by about 6%-8% with the increase of self-weight coefficient of 0.025.