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为了研究不同场地条件对高墩铁路桥梁梁体碰撞间隙需求的影响机理,也为既有桥梁的碰撞间隙宽度评估和新建桥梁碰撞间隙宽度的计算提供理论依据。首先,建立了多点激励地震动空间模型,推导了场地条件与桥梁墩底处地震加速度的关系;其次,建立了高墩铁路桥梁的有限元模型,并推导了高墩桥梁梁体碰撞间隙宽度需求量与场地条件和震级的关系;最后,以实际高墩铁路桥梁为依托,研究了不同震级不同场地分布对桥梁碰撞间隙宽度需求的影响,并与实际场地(非一致场地)分布计算结果进行对比分析。研究表明:一致场地分布时,软场地对高墩桥梁碰撞间隙宽度需求的功率谱密度峰值最大,硬场地最小,相差约4倍~6倍;实际场地时,间隙宽度的功率谱密度函数相位变化较大,碰撞次数增多;不同震级碰撞间隙宽度需求对比时,实际场地响应均值比硬、中、软一致分布场地分别大76%、71%、42%。
In order to study the influence mechanism of different site conditions on the collision clearance requirement of the high pier railway bridge, it also provides a theoretical basis for the evaluation of the collision width of the existing bridges and the calculation of the collision gap width of the new bridge. Firstly, the multi-point stimulation ground motion space model is established and the relationship between site conditions and seismic acceleration at the bottom of the bridge pier is deduced. Secondly, the finite element model of high pier railway bridge is established, and the collision gap width The relationship between demand and site conditions and magnitude; Finally, based on the actual high-pier railway bridges, the impact of different site distributions on bridge collision clearance width requirements is studied and compared with the actual site (non-uniform site) distribution calculation results Comparative analysis. The results show that the peak power spectral density of the soft ground for the requirement of high-pier bridge collision gap width is the largest when the uniform field is distributed, and the difference of the hard field is the smallest, which is about 4 times to 6 times; in the actual field, the power spectrum density function phase change Larger, and the number of collisions increased; when the collision width requirements of different magnitudes were compared, the mean value of the actual site response was 76%, 71% and 42% larger than that of the hard, medium and soft sites respectively.