悬索桥桁架加劲梁动力等效成等截面欧拉梁方法  

Simplified method for dynamic equivalent Euler beam of truss girder in suspension bridge

作　　者：祝卫亮 葛耀君[1] ZHU Weiliang;GE Yaojun(State Key Laboratory of Disaster Reduction in Civil Engineering(Tongji University),Shanghai 200092,China)

机构地区：[1]土木工程防灾国家重点实验室(同济大学),上海200092

出　　处：《哈尔滨工业大学学报》2020年第9期17-24,共8页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(51778495)。

摘　　要：针对悬索桥桁架加劲梁在数值计算、模型设计中简化问题,基于单独桁架加劲梁动力特性分析结果,以竖弯、侧弯、扭转基频相等为原则,推导并给出了不同边界条件(悬臂和两端固结)对应等截面欧拉梁等效质量惯性矩,等效抗弯刚度和等效抗扭刚度简化计算公式,然后将该计算式应用于某主跨576 m板桁结合梁悬索桥加劲梁等效分析.结果表明:基于动力特性等效方法非常简单有效;所有基于欧拉梁的等效方法均存在无法考虑桁架梁抗剪性能的缺点,越长的桁架加劲梁越接近纯弯欧拉梁,悬臂边界的桁架梁比两端固结的桁架梁更接近欧拉梁,在等效悬索桥桁架加劲梁时应选用尽量长的精细化桁架梁段和悬臂式的约束边界条件.The simplification of numerical simulation and model design of truss stiffening girder of suspension bridge is widely concerned.Based on the results of dynamic characteristics analysis of truss stiffening girder,by adopting the principle of equal fundamental frequencies of vertical bending,horizontal bending,and torsion,a simplified method was proposed for the calculation of equivalent mass moment of inertia,equivalent bending stiffness,and equivalent torsional stiffness of uniform section Euler beam under different boundary conditions(cantilever and two-end fixed types).The method was applied to the equivalent analysis of a plate-truss stiffening girder suspension bridge with main span of 576 m.Results show that the dynamic equivalent method was effective.All methods based on equivalent Euler beam had the disadvantage of not considering the shear performance of truss girder.Longer truss girder was closer to pure bending Euler beam,and truss girder of cantilever type was closer to Euler beam than two-end fixed truss girder.It is suggested to select longer delicate truss girder and cantilever boundary condition for the calculation of equivalent Euler beam of truss girder in suspension bridge.

关 键 词：桁架梁 等效 悬索桥 动力特性 欧拉梁 

分 类 号：U448.25[建筑科学—桥梁与隧道工程]