摘要
为了解采用屈曲约束支撑(BRB)作为悬索桥中央扣对悬索桥抗震性能的影响,以某主跨485 m双塔简支外张空间缆索悬索桥为背景,研究BRB中央扣的减震效果。采用SAP 2000软件建立全桥动力模型,计算不同屈服力BRB中央扣桥梁模型的地震响应,对比整体较优屈服力BRB中央扣与刚性中央扣、柔性中央扣及无中央扣桥梁模型的地震响应,并基于IDA分析和易损性方法进行桥塔地震易损性分析。结果表明:BRB中央扣屈服力不宜过大或过小,选取时应综合考虑两岸桥塔、支座、梁端的地震响应,对于背景桥梁屈服力为2000 kN时具有较优的整体减震效果;相比无中央扣模型,常规中央扣可能会放大塔底纵向内力响应,采用合理屈服力BRB中央扣能充分发挥其限位耗能功效,减震效果整体优于常规中央扣;上述4种模型中,BRB中央扣模型桥塔在各级地震作用下发生损伤的概率均最低。
In this paper,the seismic mitigation performance of buckling restrained brace(BRB)that serves as the central buckle in the stiffening girder of the suspension bridge is analyzed.Case study is carried out on a two-tower suspension bridge which has a main span of 485 m and outwardly-stressed spatial main cables.The finite element model of the overall bridge was developed by SAP 2000 to calculate the seismic responses of the bridge when BRB central buckles of different yield stresses were used.The seismic responses of models in four contexts were compared,including the conditions with BRB central buckle of good overall yield stress,rigid central buckle,flexible central buckle and without central buckle.Furthermore,the seismic vulnerability of the bridge tower was analyzed based on the IDA analysis and earthquake vulnerability analysis.The results show that the yield stress of the BRB central buckle should be selected in accordance with the seismic responses of the towers,bearings and girder ends,instead of being oversized or undersized.For the example bridge,a yield stress of 2000 kN can enable the buckle to have good overall seismic mitigation effect.Compared with the model without central buckle,the traditional central buckle is likely to amplify the longitudinal internal force response of the tower toe.The BRB central buckle with appropriate yield stress owns good restriction and energy dissipation capacity,the seismic mitigation effect of which is better than the traditional central buckle.Specifically,the model with BRB central buckle exhibited lowest probability of damage under earthquakes of different magnitudes.
作者
刘伟
宋松科
权新蕊
彭友松
漆启明
LIU Wei;SONG Song-ke;QUAN Xin-rui;PENG You-song;QI Qi-ming(Sichuan Communication Surveying&Design Institute Co.,Ltd.,Chengdu 610017,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2022年第3期61-68,共8页
Bridge Construction
基金
国家自然科学基金项目(51978581)。
关键词
悬索桥
中央扣
屈曲约束支撑(BRB)
地震响应
地震易损性
减震性能
有限元分析
suspension bridge
central buckle
buckling restrained brace(BRB)
earthquake response
seismic vulnerability
seismic mitigation performance
finite element analysis
