整体式桥梁动力特性及抗震性能研究

Dynamic characteristics and seismic performance of integral bridges

摘要:

为深入了解整体式桥梁的动力特性和抗震性能,建立台-土有限元模型,并提出合理的台-土相互作用数学模型,然后利用Midas Civil整体模型研究台-土相互作用、桩-土相互作用、桥墩构造等因素对整体式桥梁抗震性能的影响。结果表明:与简支梁相比,同等跨度下整体式桥梁的纵向刚度明显提高,但横向刚度差距不大;台后土的约束刚度大小对桥梁的静动力特性不产生明显影响,整体式桥梁根据我国现有规范计算台后地震力相对保守;改变桩-土约束刚度对整体式桥梁的抗震性能影响不大;提高桥墩的横向刚度,将独柱墩改为双柱墩能大幅提高结构抗震性能。研究结论及台后土压力系数的计算方式,可供整体式桥梁抗震计算提供参考。

Abstract:

To further gain insights into the dynamic characteristics and seismic performance of integral bridges, we established a finite-element model of abutment-soil entity and proposed a reasonable mathematical model for abutment-soil interaction. Then, the Midas Civil overall model was used to study the influences of abutment-soil interaction, pile-soil interaction, and pier structure on the seismic performance of integral bridges. Results show that compared with simply supported beams, the longitudinal stiffness of an integral bridge with the same span was considerably improved, but the difference between lateral stiffness was small. The constraint stiffness of soil behind the abutment showed no evident influence on the static and dynamic characteristics of the bridge, and the calculation of the seismic force behind the abutment of the integral bridge is relatively conservative according to the existing code in China. Increasing the lateral stiffness of bridge piers and changing single\|pillar piers to double-pillar piers can greatly improve the seismic performance of the structure. The research conclusions of this paper and the calculation method of the coefficient of earth pressure behind abutment can provide references for the seismic calculation of integral bridges.