城市大跨度钢桁拱桥抗震体系对比分析

摘要

以某城市大跨度钢桁拱桥为工程背景,以结构抗震体系及抗震性能评价为研究重点,建立了全桥空间有限元模型,采用时程反应分析方法对该桥进行了地震反应分析.结果表明:采用传统抗震体系,主拱拱脚横桥向地震反应控制主拱上部结构设计.采用传统抗震体系,在E2地震作用下桥跨下部结构保持轻微损伤很难,下部结构抗震设计困难,工程投资大幅增加.采用减隔震支座后,主拱控制截面的地震应力减震效果显著.同时该体系显著降低了V撑及桩基础的地震内力,明显降低了配筋率需求,显著提高了结构的抗震性能,工程投资节省显著.%Based on the engineering of a large span urban steel truss arch bridge, the research is focused on the structural seismic system and seismic performance evaluation. The finite element model of the whole bridge is established to define the seismic response by means of time history response analysis. The results show that the seismic response of the main arch foot in the transverse direction is the controlling factor in the design of super-structures when the traditional seismic system is applied. With the traditional seismic system, it is very difficult to maintain a slight damage to the bridge substructure subject to E2 earthquake, the seismic design of the substructure is also difficult and the engineering investment is increased dramatically. With the seismic isolation bearing, the main arch control section shows great seismic stress damping effect. At the same time, the seismic internal force of the V support and pile foundation is reduced significantly and the demand of the reinforcement is decreased dramatically with improved structural seismic performance and less engineering cost.