Abstract

The extension of high-speed railway construction to earthquake-prone regions has significantly increased the probability of trains encountering an earthquake while running on a bridge. Therefore, it is urgent to explore the applicability of the additional static quality method (ASQM) of train load simulation specified in the Code for seismic design of railway engineering. Based on comprehensively considering the uncertainty of ground motions, this paper builds spatial analysis models for train–track–bridge systems based on ASQM and the moving spring-mass column method (MSMCM), respectively. Next, it calculates the seismic responses of structures under near-fault earthquakes using a large number of samples and evaluates the applicability of ASQM through large-sample analysis. As the analysis results revealed, the statistical characteristics of over-standard ratios tend to stabilize with the increase of sample size. Under near-fault earthquakes, bearing deformation, pier shear strength, and maximum ductility all have high over-standard ratios. The seismic checking computations of bridge structures based on ASQM have failed to meet the applicability requirements, and the calculation results of the seismic responses of track structures are severely distorted. Introducing a reasonable dynamic response correction factor based on ASQM helps to effectively lower over-standard ratios, thus meeting the applicability requirements for the seismic checking computations of bridges.

摘要

高铁建设向地震多发地区延伸，大大增加了火车在桥上行驶时遭遇地震的概率。因此，迫切需要探索《铁路工程抗震设计规范》中列车载荷模拟附加静质量法（ASQM）的适用性。. 本文在综合考虑地震动不确定性的基础上，分别建立了基于ASQM和移动弹簧质量柱法（MSMCM）的列车-轨道-桥梁系统空间分析模型。其次，利用大量样本计算了结构在近断层地震下的地震响应，并通过大样本分析评估了ASQM的适用性。分析结果表明，随着样本量的增加，超标率的统计特征趋于稳定。在近断层地震下，支座变形、桥墩抗剪强度和最大延性均具有较高的超标率。基于ASQM的桥梁结构抗震校核计算未能满足适用性要求，轨道结构地震响应的计算结果严重失真。基于ASQM引入合理的动力响应修正系数有助于有效降低超标率，满足桥梁抗震验算的适用性要求。