公路简支梁桥的地震能量响应分析

Seismic Energy Response Analysis of Simple Supported Beam Bridge

利用有限元软件SAP2000建立了某公路简支梁桥的有限元模型,以7条典型强震记录为输入,研究了公路简支梁桥的地震能量响应及其分配规律。结果表明:①地基柔性效应对公路简支梁桥的地震能量响应及其分配规律的影响较小;②当场地土质变软时,地震总输入能、结构阻尼耗能和结构阻尼耗能比均呈递增趋势,而结构滞回耗能和结构滞回耗能比则不断减小,即地基土体作为桥梁动力系统的一部分,增大了系统阻尼,并分担了部分非弹性变形;③随着PGA增大,输入结构的地震能量也增加,导致塑性铰的非弹性变形增加,即结构滞回耗能和结构阻尼耗能增大。

SAP2000 is used to build the finite-element analysis(FEA) model of one simple supported beam bridge. By inputting seven typical ground motions, the seismic energy response and its distribution are analyzed based on seismic energy response equation. The results are obtained as followings: ①Effect of flexible foundation on seismic energy response and its distribution of simple supported beam bridge is less. ②As site become soften, the input seismic energy, hysteretic energy dissipation and hysteretic energy dissipation ratio increases, but damping energy dissipation and damping energy dissipation ratio decreases. It is because that damping is increased along with the foundation soil which can share part of inelastic deformation. ③With increasing of PGA, input seismic energy increases. As the result, the inelastic deformation of plastic hinge increases. It suggests that the hysteretic energy dissipation and damping energy dissipation increases too.