摘要
特大跨上承式钢管混凝土拱桥的横向刚度较弱,往往是抗震的薄弱环节。针对某跨径500m的上承式CFST拱桥在横向罕遇地震下部分拱肋间斜撑应力超限易屈曲失稳和引桥墩墩底截面横向抗震能力不足的问题,提出在拱顶段斜撑和引桥墩上设置防屈曲支撑等四种减震方案。对原桥方案和4种防屈曲支撑布置方案建立有限元分析模型并进行非线性时程分析,将4种方案各关键截面的位移、内力和抗弯能力需求比与原方案进行对比分析。结果表明:方案一对拱顶位移、拱脚和拱顶内力减震效果不明显,且对设置防屈曲支撑的拱肋段弯矩有显著增大;方案二和方案三能有效减小引桥墩墩底弯矩,但对拱肋的位移和内力无明显减小;方案四(斜撑和引桥墩设置防屈曲支撑)对全桥的位移和内力减震效果最优,对拱顶和引桥墩墩顶的最大位移减震率分别为8.4%和28.6%,对全桥关键截面的抗弯能力需求比提高效果最好,能有效提高该桥梁的整体抗震性能。
The lateral stiffness of the super large span top-loaded CFST arch bridge is weak,which is often the weak link in earthquake resistance.Because a top-loaded CFST arch bridge with a span of 500m and some of the inter-rib diagonal bracing of the arches are prone to buckling instability and the transverse seismic capacity of the pier bottom section of the approach pier is insufficient under the rare earthquake,four kinds of shock absorption schemes are proposed,such as setting up anti-buckling braces on the diagonal braces of the vault and the approach piers.A finite element analysis model is established for the original bridge scheme and four anti-buckling bracing arrangements,and the nonlinear time history analysis is carried out,the displacement,internal force and bending capacity requirement ratio of each key section of the four schemes with the original scheme are compared and analyzed.The results show that:in scheme 1,the displacement of the vault,the damping effect of the arch foot and the internal force of the vault are not obvious,and the bending moment of the arch rib section with anti-buckling bracing is significantly increased;schemes 2 and 3 can effectively reduce the bending moment at the bottom of the approach pier,but no significant reduction in the displacement and internal force of the arch rib;Scheme 4(with anti-buckling bracing on the diagonal brace and approach pier)has the best shock absorption effect on the displacement and internal force of the whole bridge,the maximum displacement damping rates for the vault and approach pier tops are 8.4%and 28.6%,respectively,scheme 4 has the best effect on improving the flexural capacity requirement ratio of key sections of the whole bridge,it can effectively improve the overall seismic performance of the bridge.
作者
刘鑫
周建庭
张瑞杰
金双双
叶丹
史俊
Liu Xin;Zhou Jian-ting;Zhang Rui-jie;Jin Shuang-shuang;Ye Dan;Shi Jun(Chongqing Jiaotong University,School of Civil Engineering,Chongqing 400074,China;Chongqing Jiaotong University,State Key Laboratory of Mountain Bridges and Tunnels Engineering,Chongqing 400074,China)
出处
《工程抗震与加固改造》
北大核心
2023年第6期68-76,共9页
Earthquake Resistant Engineering and Retrofitting
基金
国家自然科学基金项目(U20A20314)
重庆市自然科学基金项目(cstc2020jcyj-bshX0118)
重庆市教委科学技术研究项目(KJQN201900737)。
关键词
钢管混凝土拱桥
斜撑
防屈曲支撑
减震率
抗弯能力需求比
concrete filled steel tube arch bridge
diagonal bracing
buckling-restrained brace
damping rate
demand ratio of flexural capacity
