公路连拱桥在单车荷载下振动的理论和试验研究

Theoretical and Experimental Study of Highway Arcade Bridge’s Vibration under Single Vehicle Load

建立了车辆与桥梁相互作用的单轴模型的运动方程,并应用时变力学系统的求解方法进行了数值模拟.采用基于功率谱密度函数生成随机路面不平整样本的方法,由随机相位角的谐波振动的线性叠加组成的模型模拟桥面不平整,然后研究了车辆行驶速度和桥面平整度对连拱拱桥冲击系数的影响,并讨论了拱上结构效应.有限元计算结果与实测结果比较吻合,试验与理论结果表明,就本文的车、桥条件而言,现行公路桥涵设计规范中关于冲击系数的规定是偏于不安全的.

The equation of motion about single axle model of vehiclebridge interaction is established and solved by using timedependent mechanical system in the course of numerical simulation.Adopting the generating method based on power spectral density function,pavement irregularity is simulated through linear superposition of harmonic vibration which is formed by random phase angle.Then the influence of vehicle velocity and bridge carriageway pavement irregularity on impact coefficient of arcade bridge is studied, and the effect of arch superstructure is also probed.The results calculated by FEM (finite element method) in the paper coincide with the experimental data.All these lead to the conclusion: as far as the vehicle and bridge studied in the paper are concerned,regulation on impact coefficient in bridge design codes is inclined to unsafety.