多塔斜拉桥纵向约束体系研究

为确定多塔斜拉桥纵向合理的抗震约束体系,以我国某六塔斜拉桥为研究对象,分析研究了塔梁纵向四种不同固结约束下的结构动力特性和线性地震反应.计算结果表明,对于多塔斜拉桥,仅从调整塔梁纵向固结约束位置的角度出发,部分塔梁固结体系不是理想的抗震体系;塔梁纵向全固结体系和全漂浮体系都有助于减小结构地震反应在各塔的分配差异,但将纵向全漂浮的多塔斜拉桥应用于软土地基时,需关注边塔的抗震设计和结构的纵向位移.

Research on Longitudinal Constraint Systems for Multispan Cable Stayed Bridges

In order to find out the appropriate longitudinal seismic constraint system for multispan cable stayed bridge,an analysis is made of the dynamic characteristics and linear seismic response of the bridge under four kinds of rigid constraint systems between girder and different pylons in longitudinal direction based on a cable stayed bridge with six pylons in China.The results indicate that,for a multispan cable stayed bridge,only changing the positions of rigid constraints,the partial pylons constraint system is not appropriate for seismic performance; the system with all the pylons being constrained by girder or the total floating system can diminish the difference of seismic response of different pylons,but when multispan cable stayed bridges with total floating system are used in soft soil condition,special attention must be paid to the seismic design of side pylon and structural longitudinal displacement.