大跨双塔斜拉桥的动力特性与地震响应分析

Analysis of Dynamic Characteristics and Seismic Response of Long Span Cable-stayed Bridge with Double Towers

结合某大跨双塔斜拉桥工程设计实例,采用大型有限元软件ANSYS建立了三维有限元计算模型,分析了该桥的动力特性,并采用反应谱法进行了地震反应分析。研究结果表明:由于采用了半漂浮斜拉桥体系,主梁梁端位移较大,极易造成主、引桥间碰撞且对两端伸缩缝不利,可采用弹性约束或设置阻尼器等措施来限制主梁梁端位移。

Based on an engineering design case of a long span cable-stayed bridge with double towers, the three-dimensional finite element models was built by ANSYS software and the dynamic character- istics of the bridge was analyzed. The seismic response analysis was performed by employing response spectrum method. The characteristic of seismic response of the bridge was discussed. The results in- dicate that the large displacement of the girder is caused by the half-floating cable-stayed bridge sys- tem. It may cause pounding between main span and approach span, and it is also harmful to the ex- pansion joints. The measures such as elastic restraint or dampers can be used to restrain the displace- ment of the girder.