大跨度斜拉桥的地震响应分析

Seismic response analysis of long-span cable-stayed bridges

以某大跨度斜拉桥为背景,利用大型通用有限元分析软件ANSYS建立了计算仿真模型,采用分块Lanczos法得到了该斜拉桥结构的自振特性。在频域地震作用下,分别采用反应谱法和动力时程分析法对该斜拉桥在纵+竖向、横+竖向、纵+横+竖向激励作用下的地震响应进行了对比分析。分析结果表明:纵向地震激励对结构响应影响较为明显;由反应谱法计算得出的结果较动力时程分析法偏大,在弹性阶段反应谱分析结果是比较保守安全的。

Based on the background of a long-span cable-stayed bridge,this paper establishes a computational simulation model using ANSYS,a large-scale general finite element analysis software,and obtains the natural vibration characteristics of the cable-stayed bridge structure by using the block Lanczos method. Under frequent earthquakes,the seismic responses of the cable-stayed bridge under longitudinal + vertical,transverse + vertical,vertical + transverse + vertical excitations are analyzed by response spectrum method and dynamic time history analysis method respectively. The results show that the effect of longitudinal seismic excitation on the structural response is more obvious,and the results calculated by response spectrum method are larger than that by dynamic time history analysis method. Regardless of economic and reasonable factors,the results of response spectrum analysis in the elastic stage are relatively reliable.