独塔自锚式悬索桥地震响应分析

以佛山市平胜大桥为研究对象,采用空间非线性有限元法,研究了独塔自锚式悬索桥的地震响应特性;考虑了一致输入、行波输入、多点输入这3种地震动模式以及多种地震波组合,并就塔梁不同连接方式对结构响应的影响进行探讨.研究结果表明:行波效应对主梁位移响应影响较大,使得横向位移增大近80%,竖向位移增大约150%,而对结构内力影响不明显;竖向地震动分量使主塔轴力和主梁弯矩明显增大;与塔梁通过滑动支座连接相比,塔梁通过固定支座连接时主梁纵向位移显著减小,主塔弯矩显著增大,因此,在进行独塔自锚式悬索桥的抗震设计时,可在塔梁处增设阻尼器,以达到减震效果.

Seismic Response Analysis of self-anchored Suspension Bridge with Single-tower

Seismic response characteristics of self-anchored suspension bridge with single-tower were investigated with spatial nonlinear finite element method, taking Pingsheng bridge in the city of Foshan as an example. Three seismic ground motions, i.e., synchronous excitation, traveling seismic excitations and multiple-support seismic excitations, were considered, and different seismic wave superpositions were also considered. The influence of structure response by two different junctures between tower and girder was discussed. The results show that traveling seismic excitations have much effect on displacement of girder and little effect on inner force of structure. Transverse and lognitudinal displacements increase about 80% and 150% respectively under traveling seismic excitations. Axial force of tower and bending force of girder increase distinctly under vertical excitations. Girder lognitudinal displacement of fixed juncture between tower and girder is smaller than that of glide juncture between tower and girder, but bending force of tower is contrary. So damper fixed between tower and girder can be used to reduce seismic response for aseismic design of self-anchored suspension bridge with single-tower.