改变支座模型对梁式桥地震反应的影响分析

针对一座4跨梁式桥在地震作用下的反应,采用大型有限元分析程序ANSYS,选取空间梁单元建立4种模型进行了动力特性分析;并选取3条地震波,进一步对比分析了支座模型改变后连续梁桥和简支梁桥内力和位移的地震反应。结果表明:改变梁式桥支座模型,上部结构在桥台和梁端间伸缩缝处及相邻梁和桥墩间伸缩缝处相对位移的地震反应会明显变大,但桥墩内力和位移的地震反应明显减小,隔震效果显著;合理选择台梁间、墩梁处和相邻梁体间伸缩缝处限位弹簧装置的刚度可以有效地减小上部结构在地震中的相对位移,防止其发生梁端碰撞和落梁破坏。

Analysis of Influence of Changing Bearing Model on Seismic Response of Girder Bridge

Aimed at seismic response of a four-span girder bridge， four dynamic calculating model based on 3D girder element were created by finite element analysis program ANSYS．After changing the bearing model, the internal force and displacement responses  of continuous girder bridge and simple supported girder bridge subjected to the selected three earthquake waves were analysed. The results indicate that (1) the seismic responses of the relative displacement of superstructure at the expansion joints between abutment and beam end and those  between adjacent beam and pier  are significantly larger by changing the bearing model of girder bridge, but the seismic response of internal force and displacement of bridge pier decreases obviously and isolation effect is notable；(2) reasonable choice of the restrict spring stiffness at the expansion joints between abutment and beam end and those  between adjacent beam and pier can effectively reduce the relative displacement of superstructure in the earthquake to prevent the occurrence of beam end collisions and drop-beam damage.