行车荷载作用下隔震双层连续梁桥的舒适度评价

Riding Comfort Evaluation of Isolated Double-decker Continuous Bridge under Moving Vehicle Loads

连续梁桥安装铅芯橡胶支座后,由于铅芯橡胶支座的水平刚度较小,会减小桥梁的整体水平刚度,可能会影响桥梁的行车舒适度。为研究某隔震双层连续梁桥在行车荷载作用下的动力响应和行车舒适性问题,本文采用一般考虑剪切变形梁单元的三次Hermite插值函数,通过Matlab编程将车辆移动过桥时的荷载转换成梁各节点的荷载时程;然后用通用有限元程序ANSYS对行车荷载作用下隔震双层桥梁的动态响应进行时程分析。由于行车荷载主要引起桥梁的竖向振动,基本不会引起桥梁的水平振动;所以本文对其竖向振动的时程分析结果进行频谱分析,并对该隔震桥梁进行了行车舒适度评价。结果表明,该隔震桥梁满足舒适度要求。

As the result of the smaller horizontal stiffness of the lead-rubber bearings（LRB）, it can reduce the overall level of stiffness of the isolated continuous bridge, which might affect the riding comfort of the bridge. In this paper, a method is proposed for calculating dynamic response and studying riding comfort evaluation of one isolated double-decker continuous bridge under moving vehicle loads. First, the vehicle loads moving on the bridge are transformed into equivalent nodal forces （and moments） process, through Matlab programming based on the three Hermit interpolation shape functions of the general beam element considering shear deformation. And then the dynamic response of the bridge are obtained by utilizing finite element software ANSYS. Due to the vertical vibration mainly caused by moving loads, its Time-history analysis results are used to make frequency spectrum analysis. Then the riding comfort of the bridge is studied. The results show that the isolated bridge satisfies the criterion of comfort evaluation.