不同曲率空腹式连续刚构桥静动力分析

Static and dynamic analysis of open-web continuous rigid frame bridges with different curvatures

以一座空腹式连续刚构桥为工程背景,通过改变其主梁的曲率半径,分析了对以下几个方面的影响:恒载作用下结构的内力变化,地震动的最不利输入方向,结构的地震响应。计算结果表明:当曲率半径小于600 m时,恒载作用下各墩底的扭矩随曲率半径的增加而减小;而两中墩的弯矩随曲率半径的增大而减小,两边墩的弯矩亦是减小;超过600 m时,变化不大。不同地震波输入角度下,桥墩墩顶处的顺桥向和横桥向位移的最不利响应值不同时出现。不同曲率半径的桥梁结构在墩底处的弯矩和剪力变化趋势一致。随着曲率半径的不断增大,墩顶处顺桥向位移是不断增大的,墩底的顺桥向剪力和弯矩也是逐渐增大。

Taking an open-web continuous rigid frame bridge as example,this paper took the following cases into consideration which were that internal force＇s laws under dead load,the most unfavorable input direction of earthquake wave and response under earthquake load with different curvatures. Through analyses,some conclusions could be obtained. When the curvature radius is less than 600 m,the bottom torsion of every pier and the middle pier bending moment reduce with the growing radius under dead load while the side pier bending moment also gains and the response changes little when the radius exceeds 600 m. In different angles,the most unfavorable responses of top pier longitudinal and transverse displacements don＇t happen in the same angle.The tendency of bottom pier shear and bending moment is similar. With the increasing radius,the top pier longitudinal displacement grows and so are the longitudinal shear and bending moment.