双向近远场地震作用下大跨度钢桁拱桥易损性分析  

Seismic Fragility of Long-span Steel Truss Arch Bridge Under Bidirectional Near-field and Far-field Ground Motions

作　　者：刘鸣 LIU Ming(China Railway Construction Kunlun Investment Croup Co.Lad.,Chengdu Sichuan 610000,China)

机构地区：[1]中国铁建昆仑投资集团有限公司,四川成都610000

出　　处：《铁道建筑技术》2020年第12期23-27,38,共6页Railway Construction Technology

基　　金：中国铁路总公司科技研究开发计划项目(P2018G007)。

摘　　要：为探索复杂激励条件下大跨度桥梁的易损性,以某大跨度铁路上承式钢桁拱桥为研究对象建立桥梁弹塑性模型,基于概率性地震需求分析方法,选取适用性强的材料应变作为损伤指标,分析桥梁多类型构件在纵、横、双向近远场地震作用下的易损性。研究结果表明,大跨度钢桁拱桥在不同方向地震输入时,不同类型构件损伤概率存在差异;混凝土材料随地震能量增大,发生中等及严重损伤的概率大幅增加,甚至超过钢材;近远场地震造成的损伤概率差异随峰值加速度增加而增大,轻微损伤差异大于中等与严重损伤,三种类型构件中交界墩轻微损伤差异最大,为42%;1/4拱肋与跨中主梁轻微损伤概率较高,拱脚发生损伤概率较低,交界墩可能发生中等与严重损伤。In order to investigate the seismic fragility of long-span bridges under complex excitation,an elastoplastic model was established based on a long-span deck-type steel truss arch railway bridge.The material strain was selected as the damage index based on probabilistic seismic demand method to analyze fragility of bridge members under longitudinal,transverse and bidirectional near-field and far-field ground motions.The research results show that the damage probability of different types of members varies under different directions of ground motions.With the increasing of seismic energy,the moderate and severe damage probability of concrete significantly increases and even exceeds that of steel.The discrepancy of damage probability caused by near-field and far-field ground motions grows with the increase of PGA,and that of minor damage level is greater than moderate and severe damage.Moreover,for the three types of members,the discrepancy in the minor damage probability of the junction pier is the largest,42%.The minor damage probability of 1/4 arch rib and midspan beam is high,but it is low for arch foot.The moderate and serious damage may occur in junction pier.

关 键 词：大跨度钢桁拱桥 双向近远场地震 地震易损性 概率性地震需求分析 

分 类 号：U448.22[建筑科学—桥梁与隧道工程] U442.55[交通运输工程—道路与铁道工程]