某半漂浮体系多塔斜拉桥抗震性能研究

Research on Seismic Performance of a Semi-floating Multi-pylon Cable-stayed Bridge

摘要:

为开展半漂浮体系多塔斜拉桥的抗震性能研究，基于某全长1 272 m的三塔斜拉桥，建立有限元数值模型，对其进行非线性时程分析，从桥梁基本动力特性、地震响应和结构强度验证等方面进行分析比较。结果表明应用纵向黏滞阻尼器和横向耗能阻尼器，能够使得桥梁纵、横向主振型周期均避开地震峰值区间。纵桥向设置黏滞阻尼器能够有效降低结构地震响应和主梁纵向位移，降低梁端发生与相邻联碰撞的风险。横桥向采用摩擦摆支座与横向耗能阻尼器能够大幅降低桥塔、桩基的地震响应，提高桥塔在地震作用下的冗余度，并且能够有效降低桩基配筋率。半漂浮体系多塔斜拉桥采用纵向黏滞阻尼器+横向耗能阻尼器的形式，能够较好地满足桥梁抗震性能目标，为中高烈度区同类型的桥梁抗震设计提供设计参考。

Abstract:

To explore the seismic performance of a semi-floating multi-pylon cable-stayed bridge, based on a three-pylon cable-stayed bridge with a total length of 1 272 m, a finite element numerical model is established to conduct the nonlinear time-history analysis on it, which is analyzed and compared from the aspects of basic dynamic characteristics, seismic response and structural strength verification of the bridge. The results indicate that the application of longitudinal viscous dampers and transverse energy dissipation dampers can make both the longitudinal and transverse main vibration modes away from the peak seismic range. The setup of viscous dampers in the longitudinal direction can effectively reduce the seismic response of the structure and the longitudinal displacement of the girder, and the risk of collision between the girder end and adjacent beams. The use of friction pendulum bearings and lateral energy dissipation dampers in the transverse direction of the bridge can significantly reduce the seismic response of the bridge pylon and pile foundation, which improves the redundancy of the bridge pylon under the seismic action. And the reinforcement ratio of the pile foundation can be effectively reduced. The use of longitudinal viscous dampers and transverse energy dissipation dampers for the semi-floating multi-pylon cable-stayed bridges can meet the seismic performance of the bridge, which provides a reference for the seismic design of the similar bridges in medium and high intensity areas.