基于易损性的中等跨径连续梁桥合理抗震体系评估方法  

Evaluation method of reasonable aseismic system for medium-span continuous girder bridges based on fragility

作　　者：李立峰[1,2] 唐嘉豪 胡睿 尹会娜 LI Lifeng;TANG Jiahao;HU Rui;YIN Huina(School of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory for Wind and Bridge Engineering of Hunan Province,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]风工程与桥梁工程湖南省重点实验室,湖南长沙410082

出　　处：《铁道科学与工程学报》2022年第12期3665-3677,共13页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51978257);中国建筑第五工程局有限公司专项项目(2020-17)。

摘　　要：为解决中小跨径桥梁合理抗震体系分析和评估方法的问题,基于全概率抗震性能评估框架,总结基于易损性的桥梁合理抗震体系评估流程。以一座4跨连续小箱梁桥为工程背景,基于OpenSEES建立中等跨径桥梁常见的延性体系和减隔震体系精细化有限元模型,对上述2类抗震体系的抗震合理性与抗震能力进行分析,重点分析主要抗震构件的设计参数、边界约束条件等因素对桥梁抗震体系合理性的影响规律。研究结果表明:在抗震合理性和抗震能力两方面,减隔震体系总体上均优于延性体系;桥台支座通常是最易损伤的关键构件,也是导致延性体系抗震合理性相对不足的主要原因;桥墩箍筋和纵筋配筋率主要是通过影响桥墩抗震能力来影响结构抗震体系的合理性,其中,相对于箍筋配筋率,纵筋配筋率对桥墩在轻微、中等和严重损伤状态下的损伤概率影响更大;相对于增加桥台支座的高度,在桥台采用变形适应能力更大的PTFE来改善结构抗震体系合理性效果更佳;在保证结构抗震合理性的前提下,建议在低烈度区(如SA在0~0.4g左右)内选用延性体系,在中、高烈度区(如SA在0.4g~0.9g左右)选用减隔震体系,以提高桥梁结构抗震能力。In order tosolve the problem of the analysis and evaluation method of the reasonable aseismic system of small and medium-span bridges, based on the full-probability seismic performance evaluation framework, a reasonable aseismic system evaluation process based on the fragility of the bridge was summarized. Taking a 4-span continuous small box girder bridge as the engineering background and establishing a refined finite element model of ductility system and seismic isolation system for medium-span bridges based on OpenSEES. Finally, the aseismic rationality and seismic capacity of the above-mentioned two types of aseismic systems were analyzed and focused on the influence of the design parameters of the main aseismic components, boundary constraints,and other factors on the rationality of the bridge aseismic system. The test results show the seismic isolation system is generally superior to the ductile system in terms of seismic rationality and seismic capacity;Abutment bearing is usually the most vulnerable key component, which is also the main reason for the relative lack of seismic rationality of ductile system. The stirrup and longitudinal reinforcement ratio of the pier mainly affect the rationality of the structural seismic system by affecting the seismic capacity of the pier. The reinforcement ratio of stirrup and longitudinal reinforcement of bridge pier mainly affects the rationality of structural seismic system by affecting the seismic capacity of bridge pier. Compared with the reinforcement ratio of the stirrup, the reinforcement ratio of longitudinal reinforcement has a greater impact on the damage probability of the bridge pier under mild, moderate, and severe damage conditions;under the premise of ensuring the rationality of the bridge aseismic system, it is recommended to select the ductile system in the low-intensity area(SA between 0and 0.4g) and the seismic reduction and isolation system in the medium and high-intensity area(SA between 0.4g and 0.9g) to improve the seismic capacity of the bridge

关 键 词：桥梁工程 中等跨径桥梁 合理抗震体系 易损性分析 系统可靠度 

分 类 号：U441[建筑科学—桥梁与隧道工程]