脉冲型近场地震作用下列车-简支梁桥的耦合振动

相比中远场地震,近场地震含有高能速度脉冲,会激发结构显著的位移响应。为研究该速度脉冲对高速铁路简支梁桥车桥系统动力响应的影响,采用三角函数法模拟速度脉冲,并与无脉冲的远场地震叠加,合成不同脉冲类型、脉冲周期和脉冲幅值的脉冲型近场地震动,以跨径32 m的典型高速铁路简支梁桥为例,采用自编的车-轨-桥-地震分析程序TTBSAS进行仿真计算,详细探讨脉冲参数对车桥系统动力响应的影响。结果表明:近场地震速度脉冲会显著增大高速铁路简支梁桥车桥系统的动力响应,在近场区域的车桥耦合振动分析中,不能忽略速度脉冲的影响;脉冲类型、脉冲周期和脉冲幅值对简支梁桥位移的影响远大于桥梁加速度和桥上列车的行车安全性指标,在选取速度脉冲参数时可不考虑桥上列车的影响;在本文计算条件下,双半波脉冲和三半波脉冲近场地震作用下桥梁的动力响应幅值明显大于单半波脉冲,且当脉冲周期为2.0 s时车桥系统的动力响应最大。

Coupling vibration analysis of train-simply supported beam bridge under near-field earthquake with pulse

Compared with the medium-field and far-field earthquake, the near-field earthquake contained velocity pulse of high-energy, which would introduce significant displacement of the structure. To study the influence of the velocity pulse on Train-Bridge System (TBS) of high-speed railway Simply Supported Beam Bridge (SSBB), the trigonometric function method was used to simulate the velocity pulse and superimpose with the far-field earthquake without pulse to synthesize the pulse type near-site earthquake with different pulse types, pulse periods and pulse amplitude. Taking a typical high-speed railway SSBB with a span of 32 m as an example, the simulation was carried out by using the self-designed program of TTBSAS. The near-field seismic velocity pulse can significantly increase the dynamic response of the TBS of the high-speed railway SSBB, and the influence of the velocity pulse cannot be ignored in analysis of TBS coupling vibration in the near field. The influence of pulse type, pulse period and pulse amplitude on the displacement of SSBB is much greater than that of bridge acceleration and train safety index, and the influence of train on bridge cannot be considered in selection of pulse parameters. The dynamic response amplitude of the bridge under the near-field earthquake action of double half-wave pulse and three-half-wave pulse is obviously larger than that of single half-wave pulse, and the dynamic response of TBS is the largest when the pulse period is 2.0 s.