中小跨径梁桥地震易损性研究

为对桥梁系统地震易损性进行准确评估,结合Copula函数技术,提出基于串-并联组合体系的桥梁系统易损性分析方法。桥墩是桥梁抗震中的控制构件且较难修复,采用串联体系将多个桥墩进行组合,对于修复难度较低的桥台及支座构件,采用并联体系进行模拟。在此基础上,将桥墩、桥台及支座三类构件体系进行串联,构成桥梁系统的串-并联组合体系。以三跨连续箱梁桥为例,阐明了基于串-并联体系的桥梁系统易损性分析方法,并将分析结果与基于串联体系的桥梁系统易损性进行对比。结果表明:对于中小跨径的连续梁桥,基于单一串联体系会明显高估桥梁系统的易损性,相对于串-并联体系,在轻微、中等、严重及完全四种破坏状态下,其中位值偏差在纵桥向分别为22.2%、20.7%、20.5%及24.6%;在横桥向分别为30.0%、16.1%、9.8%及11.3%,基于串-并联组合体系建立桥梁系统地震易损性更切实合理。

Seismic vulnerability analysis of small and medium span girder bridges

In order to accurately evaluate the seismic vulnerability of bridge systems, a new vulnerability analysis method of the bridge system based on series-parallel system and Copula function technology is proposed.The pier is a control component in the bridge and is difficult to be repaired after earthquakes.Bridge piers are combined by a series system.For bridge abutments and bearings which are less difficult to be repaired, a parallel system is used to simulate them.The three types of component classes are then connected in the series form, and a series-parallel system of the bridge system is developed.A three-span continuous box girder bridge is used to illustrate the seismic vulnerability analysis method of bridge systems based on the series-parallel system.The results are compared with the system vulnerability based on the series system.The results show that the vulnerability of the small and medium span continuous bridge system is significantly overestimated based on a simple series system.Compared with the series-parallel system, deviations of the vulnerability medians in the longitudinal direction are 22.2%, 20.7%, 20.5% and 24.6% for slight, medium, severe and complete limit states, respectively.The deviations in the transverse direction are respectively 30.0%, 16.1%, 9.8% and 11.3% for the four limit states.The seismic vulnerability of the bridge system based on the series-parallel system is more realistic and reasonable.