大跨度钢管混凝土拱桥的动力冲击系数分析

The Analysis of Impact Factor on Concrete Filled Steel Tubular Arch Bridge with Long Span

在桥梁设计中,考虑车桥耦合振动的影响,精确确定结构受到的冲击效应是非常必要的。以茅草街钢管混凝土拱桥和常见的三轴货车为例,分别利用有限元法和动力平衡原理建立了结构分析模型和车辆的多刚体动力学模型。考虑桥面不平顺的影响,利用车桥系统的协调条件,用Newmark-β法求解振动微分方程,计算桥梁结构动力响应,分析桥梁冲击系数。结果表明:考虑车桥耦合振动的影响,冲击系数通常大于按规范计算的结果;冲击系数随路面不平度的增加而快速增大;车速对冲击系数的影响具有一定的随机性,通常存在某一车速使冲击效应最明显;吊杆截面面积的增加使冲击系数大致呈减小趋势,但具有不确定性。

It is necessary to consider the effects of vehicle-bridge coupled vibration and accurately determine the impact of vehicles on the the structure.The Maocaojie concrete filled steel tubular arch bridge and common 3-axle truck are taken as example to respectively establish the analytical model of structure and multi-rigid-body dynamic model of vehicle according to finite element method and dynamic equilibrium principle.The bridge surface roughness is taken into account,and the compatible conditions of vehicle-bridge system are used in calculation.The Newmark-β method is used to solve the differential equations,and the dynamic responses of structure and impact factors are calculated and analyzed.The results indicate that the impact factors obtained when considering the effects of vehicle-bridge coupled vibration are usually larger than those obtained by code;the impact factors increase rapidly with the increment of bridge surface roughness;the effects of vehicle velocity on the impact factors are random and there usually exists a velocity that makes the impact be significant;the increase of the hanger section area generally leads to decrease of the impact factors,while there is uncertainty.