车辆作用下等截面低墩连续刚构桥与连续梁桥动力响应对比分析

Comparative Analysis of Dynamic Response between Continuous Rigid Frame Bridge and Continuous Bridge with Constant Cross Section and Low Pier under Vehicle

目的研究某等截面低墩连续刚构桥的车致振动响应问题,对比分析相同跨径布置下不同桥梁结构类型(连续梁桥和连续刚构桥)的车桥耦合动力响应。方法运用ANSYS软件建立桥梁空间有限元模型,采用9自由度空间车辆模型,通过模态综合法和Newmark-β数值积分方法对车桥耦合方程进行迭代求解。结果连续刚构桥跨中挠度大于连续梁桥,跨中正弯矩和墩顶负弯矩小于连续梁桥,连续刚构桥和连续梁桥的第一跨跨中弯矩和挠度均大于第二跨跨中弯矩和挠度。结论与同跨径连续梁桥相比,墩梁固结的连续刚构桥可以减小主梁正、负弯矩;连续刚构桥的冲击系数需按竖弯振型特征频率计算。

The purpose of this paper is to study the vehicle-bridge coupling vibration response of a continuous rigid frame bridge with constant cross section and low pier.The dynamic responses of continuous rigid frame bridge subjected to a moving vehicle were compared with the dynamic responses of a continuous bridge with the same cross section and span layout.The software of ANSYS was used to build the bridge space finite element model and the vehicle was simplified to a 9-degree-of-freedom model.The model of vehicle-bridge coupling vibration was solved through the Newmark-β numerical integration method while the modal synthesis superposition technology was used in the model.The results show that the mid-span deflection of continuous rigid frame bridge is larger than that of continuous bridge,and the positive bending moment in the mid-span and the negative bending moment on the top of the pier are smaller than the continuous bridge.Both the bending moment and deflection of the first mid-span of the continuous rigid frame bridge and the continuous bridge are greater than the bending moment and deflection of the second mid-span.Compared with the continuous bridge of the same span,continuous rigid frame bridges with piers and beams consolidation can reduce the positive and negative bending moments of the main beam.The impact coefficient of the continuous rigid frame bridge needs to be calculated according to the characteristic frequency of the vertical bending mode.