改善斜风下悬索桥施工期颤振稳定性措施研究  

Study on measures to improve flutter stability of suspensionbridges under skew wind during construction

作　　者：张新军[1] 何智超 李博林 赵晨阳 ZHANG Xinjun;HE Zhichao;LI Bolin;ZHAO Chenyang(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学土木工程学院,浙江杭州310023

出　　处：《浙江工业大学学报》2023年第2期160-170,共11页Journal of Zhejiang University of Technology

基　　金：浙江省自然科学基金资助项目(LY18E080034);浙江省公益技术应用研究项目(LGF22E080018)。

摘　　要：为确保斜风下大跨度悬索桥施工期的颤振稳定性,结合润扬长江大桥南汊悬索桥,采用斜风下大跨度桥梁三维精细化颤振分析程序,分析斜风下加劲梁由跨中至两侧桥塔对称架设过程颤振稳定性的变化规律,指出斜风下悬索桥颤振稳定性薄弱的施工阶段。在此基础上,提出并分析主梁由两侧桥塔至跨中对称架设和由跨中至两侧桥塔非对称架设两种方法对提高斜风下悬索桥施工期颤振稳定性的有效性,探索适宜的悬索桥主梁架设方法。研究结果表明:斜风作用会显著降低施工期悬索桥的颤振稳定性;主梁采用由跨中至桥塔方向拼装时,架设初期(拼装率小于20%)和中后期(拼装率为40%~80%)是悬索桥施工面临的两个颤振稳定性低谷期;主梁采用由两侧桥塔至跨中对称架设方法能显著提高主梁架设初期的颤振稳定性,而且整个施工期的颤振稳定性基本都能满足要求,总体平均增幅为34.2%;主梁由跨中至两侧桥塔非对称架设时,颤振临界风速并非随着偏心率增大而单调递增,呈现出先增大后降低的趋势,并在8.6%偏心率下达到峰值,在最优偏心率下施工全过程的颤振稳定性相比对称架设方法有显著提升,总体平均增幅为14.5%;从颤振稳定性角度而言,加劲梁采用由两侧桥塔至跨中对称架设方法最好,其次为跨中至两侧桥塔的非对称架设方法,传统的跨中至两侧桥塔对称架设方法最差。In order to ensure the flutter stability of long-span suspension bridges under skew wind during erection,by taking the south branch suspension bridge of Runyang Bridge over the Yangtze River as example,the evolution of flutter stability of the bridge under skew wind during the symmetric erection of the deck from the midspan to the towers is investigated numerically by the computational procedure of three-dimensional refined flutter analysis of long-span bridges under skew wind,and the erection periods with weak flutter stability are pointed out.On this basis,two methods of symmetrical towers-to-midspan erection and nonsymmetric midspan-to-towers erection are put forward,their effectiveness to improve the flutter stability of suspension bridges during erection is assessed,and the favorable deck erection method of suspension bridges is proposed.The results show that the flutter stability of suspension bridges during erection is significantly reduced by the skew wind effect.When the deck is erected by the traditional symmetric midspan-to-towers method,weak flutter stability occurs during the early period(below 20%erection ratio)and the middle-later period(40%to 80%erection ratio).By using the symmetrical towers-to-midspan erection sequence,the flutter stability during the early period is significantly improved and good flutter stability is basically guaranteed during the whole construction period.The flutter critical wind speed increases by an average value of 34.2%compared with the symmetric midspan-to-towers erection method.In the case of nonsymmetric midspan-to-towers erection,the flutter critical wind speed does not increase monotonically with the eccentricity,showing a trend of first increasing and then decreasing,and reaches the peak at an eccentricity degree of 8.6%.Under the optimal eccentricity,the flutter stability throughout the construction process is significantly improved compared with the symmetrical erection method and the average increase is 14.5%.In terms of flutter stability,the symmetrical towers

关 键 词：斜风 悬索桥 施工期 颤振稳定性 主梁架设方法 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]