大跨度悬索桥气动稳定性随跨径演变规律  

EVOLUTION LAW OF AERODYNAMIC STABILITY OF LONG-SPAN SUSPENSION BRIDGES WITH INCREASING SPANS

作　　者：丁叶君 赵林[1,2,3] 鲜荣 刘高 肖海珠 葛耀君[1,2] DING Ye-jun;ZHAO Lin;XIAN Rong;LIU Gao;XIAO Hai-zhu;GE Yao-jun(State Key Lab of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Transport Industry of Wind Resistant Technology for Bridge Structures,Tongji University,Shanghai 200092,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Guangdong Highway Construction Co.,Ltd.,Guangzhou,Guangdong 510600,China;CCCC Highway Bridges National Engineering Research Center Co.,Ltd.,Beijing 100088,China;China Railway Major Bridge Reconnaissance and Design Institute Co.,Ltd.,Wuhan,Hubei 430056,China)

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]同济大学桥梁结构抗风技术交通运输行业重点实验室,上海200092 [3]重庆交通大学省部共建山区桥梁及隧道工程国家重点实验室,重庆400074 [4]广东公路建设有限公司,广东广州510600 [5]中交公路长大桥建设国家工程研究中心有限公司,北京100088 [6]中铁大桥勘测设计院集团有限公司,湖北武汉430056

出　　处：《工程力学》2023年第12期194-202,共9页Engineering Mechanics

基　　金：国家自然科学基金项目(52078383,52008314);土木工程防灾国家重点实验室自主课题项目(SLDRCE19-B-11)。

摘　　要：气动失稳是大跨度悬索桥设计中的关注重点之一。为了在悬索桥初步设计阶段,给主梁断面形式和跨径长度的确定提供参考,对主跨1000 m~5000 m悬索桥开展气动稳定性分析。基于跨径从888 m(虎门大桥)~1991 m(明石海峡大桥)的悬索桥动力特性,拟合在1000 m~5000 m跨径范围内主梁侧弯、竖弯与扭转基频随跨径增长的变化趋势。根据该趋势构建主跨介于1000 m~5000 m的双塔单跨悬索桥有限元模型,其中垂跨比为1/11。选取常用的流线形单箱、格构式桁架、窄开槽双箱与宽开槽双箱4种主梁断面,将主梁宽度统一为36 m以排除桥宽对气动稳定性的影响。结合风洞试验测得的静力三分力系数和颤振导数,采用考虑结构几何非线性和气动荷载非线性的三维非线性静风稳定分析方法及三维全模态频域颤振分析方法求解悬索桥在0°与±3°攻角的静风失稳临界风速和颤振临界风速。分析结果表明,跨径从1000 m增加到3000 m左右时静风失稳临界风速有下降趋势,在3000 m~5000 m时静风失稳风速随跨径增大而上升。颤振临界风速则随跨径不断降低,与主梁基频的衰减规律相似。对不同断面外形气动稳定性的比较显示,流线形单箱和格构式桁架悬索桥的最低静风失稳临界风速低于实测最大阵风风速的80 m/s;跨径超过2000 m时,四种断面悬索桥的颤振临界风速均小于70 m/s。研究结果表明,对于本文构建的悬索桥而言,跨径3500 m附近的流线形单箱和格构式桁架悬索桥有可能在现实中发生静风失稳,而颤振在大跨度悬索桥抗风设计中是控制因素,且颤振问题随跨径增大而越发严峻。Aerodynamic instability is one of the significant concerns in the design of long-span suspension bridges.To provide reference for the determination of decks and spans length in the preliminary design stage of suspension bridges,the aerodynamic stability analysis of suspension bridges with spans from 1000 m to 5000 m was carried out.Based on dynamic characteristics of existing suspension bridges with spans from 888 m(Humen Bridge)to 1991 m(Akashi-Kaikyo Bridge),the developing trends of natural frequencies were discussed.Following developing tendency,finite element models(FEMs)of suspension bridges with spans from 1000 m to 5000 m were established,and the sag to span ratio was 1/11.Four commonly used forms of bridge decks were selected,i.e.,single box section(SBS),latticed truss section(LTS),narrow slotted section(NSS)and wide slotted section(WSS).All the widths of decks were adjusted to 36 m with influence on aerodynamic stability excluded.3-D nonlinear aerostatic instability analysis considering structural geometric nonlinearity and aerodynamic load nonlinearity and 3-D frequency domain flutter analysis were carried out,in which the aerodynamic parameters such as static aerodynamic coefficients and flutter derivatives were obtained from wind tunnel tests.Aerostatic instability wind speeds and flutter critical wind speeds of suspension bridges at 0°and±3°angle of attack were calculated.The results show that aerostatic instability wind speeds have a decrement with spans from 1000 m to 3000 m.However,aerostatic instability wind speeds rise up with spans increasing between 3000 m and 5000 m.Flutter critical wind speeds continuously decrease with spans growth,similar to the decrement of torsional natural frequencies of main girder.Moreover,a comparison of aerodynamic stability by sections were studied.It shows that the minimum aerostatic instability wind speeds of suspension bridges with SBS and LTS decks are lower than the maximum gust wind speed of 80 m/s in measurement.It is also found that bridges with all four

关 键 词：桥梁工程 大跨悬索桥 有限元分析 静风失稳 颤振 气动外形 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]