曲线梁桥预应力作用效应分析

Analysis of Prestressed Effects on Curved Girder Bridge

针对预应力混凝土曲线梁桥空间受力问题,基于曲线梁预应力等效荷载理论,采用Visual C++编写了相应的预应力混凝土曲线梁桥等效荷载计算程序。采用该程序进行了简支曲线梁预应力等效荷载效应计算,并将计算结果与实体力筋模拟结果进行了比较;以某三跨预应力混凝土曲线连续梁桥为例进行了曲线连续梁桥预应力效应分析与优化研究。结果表明:基于预应力等效荷载理论编写的曲线梁桥预应力等效荷载计算程序可准确分析曲线梁预应力效应;预应力混凝土曲线梁桥关键截面内力及位移响应绝对值总体上随曲率半径的增加而减小,当曲率半径超过200m时,变化趋势趋缓。采用预应力钢束合力重心线布置预应力钢束可有效改善曲线梁主梁扭转角及扭矩沿跨径方向分布;设置中支座预偏心距对承载能力极限状态作用下曲线梁主梁扭转角及扭矩沿跨径方向的分布具有一定的改善作用,而对预应力作用下主梁扭转角和扭转沿跨向分布改善不明显。

Aiming at the spatial stress problem of the prestressed concrete curved girder bridges,based on the prestressed equivalent load theory of curved girder,the equivalent load calculation program of prestressed concrete curved girder bridge was developed using Visual C++.The program was used to calculate the prestressed equivalent load of the simply supported curved girder,and the calculated results were compared with the results of the solid element combined prestressed steel model.A three-span prestressed concrete curved continuous girder bridge was taken as an example to carry out the analysis of prestressed effects and optimization research.The results show that the prestressed equivalent load calculation program of curved girder bridge based on prestressed equivalent load theory could accurately analyze the prestress effects of curved girder.The absolute values of the force and displacement responses of the key section of the prestressed concrete curved girder bridge decreased with the increase of the radius of the curved girder bridge,and the trend of change slowed down when the radius exceeded 200 m.The distribution of the torsional angle and torques of the curved girder bridge could be effectively improved by arranging the prestressed tendons along the center line of the prestressed tendons.By setting the pre-eccentricity of the bearing of the curved continuous girder bridge,the distribution of torsional angle and torque along the bridge axis direction could be improved in certain degree under ultimate limit state(ULS),but the distribution of torsion angle and torque of the curved girder bridge could not be improved obviously under prestressing load.