大跨桥∏形主梁断面气动导纳的试验识别  

Experimental Recognition of Aerodynamic Admittance of ∏-Shape Main Girder Cross Section of Long Span Bridge

作　　者：诸葛萍[1] 卢彭真[1] 孙延国[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《桥梁建设》2009年第5期17-20,共4页Bridge Construction

摘　　要：准确的气动导纳值是抖振精细化分析的前提,比较切合实际的桥梁断面气动导纳函数目前只能通过风洞试验进行考察。通过风洞试验对大跨桥∏形主梁断面气动导纳进行研究,气动导纳的识别理论采用等效气动导纳法,考察∏形主梁断面气动导纳变化规律,并对试验中获得的3个气动导纳曲线进行拟合,得出拟合后的气动导纳曲线表达式,试验结果表明:∏形桥梁断面阻力导纳函数和升力导纳函数随折减频率的增大有递减的趋势,而对于力矩导纳则呈现出先增后减的趋势,现行桥梁规范中采用Sears函数对∏形断面进行抖振分析存在较大的误差。The correct value of aerodynamic admittance is the precondition for the refined analysis of bridge buffeting. Currently, the aerodynamic admittance functions suitable for the actual conditions of bridges can be only recognized in wind tunnel tests. Through the wind tunnel test, the aerodynamic admittance of the Ⅱ-shape main girder cross section of a long span bridge is studied and the theory used in the study is the equivalent aerodynamic admittance method. The variation laws of the aerodynamic admittance of the girder cross section are investigated, the three admittance curves obtained in the test are fitted and the expressions for the fitted admittance curves are established. The results of the experiment demonstrate that the drag and lift aerodynamic admittance functions of the cross section have the tendency to decrease with the increase of the reduction frequency while for the moment aerodynamic admittance, the admittance is in the tendency to increase first and decrease late. The Sears function adopted in the present bridge codes has considerable errors when used for the buffeting analysis of the Ⅱ-shape main girder cross sections of bridges.

关 键 词：长跨桥 ∏形梁 抖振 气动导纳函数 风洞试验 

分 类 号：TU311.3[建筑科学—结构工程]