地震作用下高墩铁路桥梁梁体碰撞间隙宽度需求机理分析

发布时间：2019-02-16 11:28

【摘要】：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%。
[Abstract]:In order to study the influence mechanism of different site conditions on the impact clearance demand of railway bridges with high piers, it also provides a theoretical basis for the assessment of the impact clearance width of the existing bridges and the calculation of the impact clearance width of the new bridges. Firstly, the spatial model of multi-point excitation ground motion is established, and the relationship between the ground condition and the seismic acceleration at the bottom of the bridge pier is deduced. Secondly, the finite element model of railway bridge with high piers is established, and the relationship between the width of collision clearance and the site condition and magnitude is deduced. Finally, based on the actual high-pier railway bridge, the influence of different earthquake magnitude and site distribution on the gap width demand of the bridge is studied, and the results are compared with the actual site (non-uniform site) distribution. The results show that when the site distribution is consistent, the peak value of the power spectrum density of the soft site for the gap width of the high pier bridge is the largest, and the hard site is the smallest, the difference is about 4 ~ 6 times. In the actual site, the power spectral density function of gap width changes greatly, and the number of collisions increases. When the gap width of different magnitudes is compared, the actual site response is harder than the average value, and the soft uniform distribution of the site is larger than 76 / 71a / 42s respectively.
【作者单位】：西南交通大学土木工程系;北京工业大学城市与工程安全减灾教育部重点实验室;西南交通大学土木工程学院;
【基金】：中国博士后基金项目(2015M580031) 国家自然科学基金项目(51308645,51508473) 中央高校基金项目(2682014CX004EM)
【分类号】：U442.55

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