多跨钢-混凝土组合连续梁桥冲击系数研究

Research on impact coefficient of multi-span steel-concrete composite continuous beam bridge

为计算钢-混凝土组合连续梁桥冲击系数,基于自编程序建立了车-桥耦合非线性模型进行参数化分析。基于MATLAB采用功率谱函数生成了桥面随机不平顺曲线,综合考虑了行车速度、行车方式和桥面平整度对组合连续梁桥冲击系数的影响。结果表明:单线行驶下,行车速度在60~120 km/h时,组合连续梁桥冲击系数随着车速增加而增加,高速行驶下第2跨冲击系数要大于第1跨,最大局部冲击系数出现在悬臂板自由端,冲击系数与主梁空间刚度分布有关。随着桥面平整度由好变差,冲击系数呈现出非线性增长,尤其是由C级(一般)到D级(差),最大整体冲击系数由0.167增加到0.588,最大局部冲击系数由0.194增加到0.658;行车方式对组合连续梁桥冲击系数有一定的影响。最后通过与不同规范的计算结果对比,对钢-混凝土组合连续梁桥冲击系数取值给出了建议。

In order to calculate impact coefficient of steel-concrete composite continuous beam bridge, the vehicle-bridge coupling nonlinear model is established to perform parametric analysis based on self-compiled program. The bridge surface random irregularity curve is created by power spectrum function through MATLAB, the influences of vehicle speed, running mode and bridge surface roughness on impact coefficients of steel-concrete composite continuous beam bridge are considered. The results indicate that under one-line driving, the impact coefficient increases with the increasing of vehicle speed when it is in the range of 60~120 km/h, and the impact coefficient of the second span of composite continuous beam bridge is bigger than that of the first span under high speed. The maximum local impact coefficient occurs at the free end of cantilever plate,and the impact coefficient is related to the spatial stiffness distribution of the primary beam. The impact coefficient presents nonlinear increase as the bridge surface roughness changes from good to bad, especially when it changes from grade C to grade D. The maximum global impact coefficient increases from 0.167 to 0.588, and the maximum local impact coefficient increases from 0.194 to 0.658. The running mode has a certain influence on impact coefficient of composite continuous beam bridge. Finally, the suggestion for the value of the impact coefficient of concrete-steel composite beam bridge is provided according to the comparison with different calculated results of specifications.