地震条件下高速铁路桥上接触网系统安全阈值

Safety Threshold for Catenary System on Bridge of High Speed Railway under Earthquake

采用有限元分析软件ABAQUS建立桥上接触网系统动力学模型,对受到不同频谱特性和强度地震波激励下不同墩高简支梁桥上接触网系统进行地震响应分析,研究地震作用下高速铁路桥上接触网系统地震动强度的安全阈值。结果表明:在不同频谱特性的地震波激励下,桥上接触网系统的动力响应不同,其中以天津波激励下的桥上接触网系统动力响应最明显,迁安波激励下的桥上接触网系统动力响应最弱;随着地震动强度的增大以及墩高的增加,桥上接触网系统的动力响应随之增大,安全性降低,因此,桥上接触网系统地震动强度的安全阈值应随着桥墩高度的增加而降低;地震作用下桥上接触网系统的导线变形最大;桥上接触网支柱(含腕臂)的变形主要为腕臂变形,表现为垂直于线路方向的振动;依据计算得到25m墩高桥梁的桥上接触网系统最不利情况下的地震动强度限值为0.127g,考虑一定安全冗余,建议墩高25m以下的32m简支梁桥桥上接触网系统地震动强度的安全阈值为0.12g。

The dynamics model of catenary system on bridge was built by ABAQUS finite element analysis software to analyze the seismic response of the catenary system on simply-supported girder bridge with different pier heights under the excitations of seismic waves with different spectral characteristics and intensity.The safety threshold for the ground motion intensity of catenary system on bridge of high speed railway under earthquake was studied.The results indicate that,under the excitations of seismic waves with different spectral characteristics,the dynamic responses of catenary system on bridge are different.Among them,the dynamic response excited by Tianjin wave is the most significant,and that excited by Qianan wave is the weakest.With the increase of both the ground motion intensity and pier height,the dynamic response of catenary system on bridge increases while safety decreases.Accordingly,the safety threshold for the ground motion intensity of catenary system on bridge should be lowered with the increase of pier height.The deformation of contact wire is the maximum in catenary system on bridge under earthquake.The deformation of catenary mast（including cantilever）on bridge is mainly cantilever deformation,which is characterized as the vibration perpendicular to line direction.Based on the calculated limit of0.127 g for the ground motion intensity of catenary system on bridge with 25 mpier height in the worst case,considering certain safety redundancy,the proposed safety threshold should be 0.12 g for the ground motion intensity of catenary system on 32 msimply-supported girder bridge with the pier height below25 m.