车-桥-墩耦合系统演变随机振动分析

Evolutionary random vibration analysis of coupled vehicle-bridge-pier systems

将梁简化为两端简支的欧拉-伯努利梁模型,桥墩简化为底部固结的柱,考虑两自由度车辆移动系统与桥面结构表面接触处不平整产生的随机激励,建立了移动车辆系统-桥-墩的耦合力学分析模型。根据子结构方法和演变随机过程一般理论,并应用模态分析法对车-桥-墩耦合系统进行随机振动分析,推导得到了桥墩位移、桥墩轴力、梁竖向位移协方差函数和均方值响应的理论计算公式。通过数值算例,比较了跨中位移的确定性响应和跨中位移的均方根值响应,讨论了在不同桥墩高度、不同车辆移动速度、不同桥面等级下桥梁跨中竖向位移均方根、桥墩轴力均方根的变化规律。

The coupling random vibration of vehicle-bridge-pier is studied.The bridge is modeled as a continuous Euler-Bernoulli beam simply supported at both ends.The piers are considered to be columns fixed at the bottoms and the vehicle is considered to be a two-DOF system with linear suspensions and tiring flexibility.The influence of the surface irregularity of bridges is considered.According to substructure,general theory of evolutionary random process and modal analysis,the covariance functions and the mean square values of pier-displacement,pier-axial force,beam-displacement are derived.The effect of the road surface roughness,the vehicle speed and the height of the pier on the root mean square of the deflection of beam and the axial forces of the pier are discussed.