基于全寿命周期成本的高速铁路连续梁桥减隔震方案研究

Research on Seismic Isolation Schemes of High-speed Railway Continuous Girder Bridge Based on Life Cycle Cost

高烈度地震区大跨度连续梁桥一般采用减隔震设计以减小结构地震响应及由此带来的经济损失,而不同的减隔震方案亦决定着结构的抗震性能和初始成本。为了从抗震性能和经济性两方面综合评价连续梁桥减隔震设计的合理性,以一座高烈度地震区高速铁路大跨度连续梁桥为背景,设计多种减隔震布置方案开展桥梁系统地震易损性分析,并基于全寿命周期成本最小准则探讨了该连续梁桥在全寿命期内各减隔震方案的经济性。结果表明:全桥采用双曲面球型隔震支座和液体黏滞阻尼器配合使用方案是全寿命周期地震损失最小的方案,但高达622×104 元的减隔震措施费用引起桥梁初始成本过高,致使该方案经济性较差;全桥布置双曲面球型隔震支座、边墩配置液体黏滞阻尼器的方案在满足抗震设防要求的同时,大幅降低了桥梁初始成本,实现了结构减隔震措施造价与损失期望的有机平衡,为本算例桥梁减隔震设计中的最优方案。作者提出的桥梁减隔震方案研究方法有效弥补了当前在减隔震设计中主要考虑桥梁抗震性能而忽略其经济效益的不足,实现了结构抗震性能与其经济效益的双目标评价,为利益相关者对桥梁减隔震方案的合理决策提供了新思路。

In the seismic design of long-span continuous beam bridges in high intensity seismic area,isolation devices are generally used to reduce the seismic response and economic losses of structures,and different arrangements of isolation measures often determine the seismic performance and initial cost of structures.In order to comprehensively evaluate the rationality of seismic isolation design of continuous girder bridge from its anti-seismic and economic performance,a high-speed railway continuous girder bridge in the high-intensity seismic area was taken as the background.A variety of seismic isolation schemes were designed to carry out seismic vulnerability analysis,and the economics of each scheme during the whole life of the bridge was discussed based on the minimum life cycle cost criterion.The results show that the whole bridge could use the hyperbolic spherical isolation bearing and the viscous damper to minimize the earthquake loss during the whole life cycle,but the initial cost of the bridge was too high due to the cost of isolation measures,which led to the poor economy of this scheme.While,equipping the whole bridge with hyperboloid spherical isolation bearings and side piers with viscous dampers was the optimal scheme in the seismic isolation design of the bridge,which met the requirements of seismic fortification,greatly reduced the initial cost and achieved balance between the cost of structural isolation measures and expected loss of the bridge.Facing with the problem that the current bridge seismic isolation scheme designs were mainly considering the seismic performance of bridge but ignoring its economic benefits,the research method of bridge seismic isolation scheme presented in this paper realized the double objective evaluation of structural seismic performance and economic benefit,which would provide a new idea for stakeholders to make reasonable decision on bridge seismic isolation scheme.