悬索桥施工猫道静风失稳机理分析

采用风洞试验和程序分析相结合的方法分析猫道的静风失稳机理;根据节段模型静力三分力风洞试验结果对猫道有限元模型加载,进行猫道非线性静风响应计算,分析猫道承重绳张力和位移随风速变化。计算结果表明,猫道发生静力扭转失稳的原因是空气力矩的作用使猫道面层处于正攻角,当风攻角较小时,升力系数可能为负值,即升力方向向下,风攻角逐渐增大时,升力系数转为正值,大小随风攻角的增大而增大。当风速提高同时攻角增大到一定程度时,向上的升力使部分承重绳的张力产生松弛,猫道扭转刚度减小,不能抵抗空气力矩的作用,导致猫道扭转失稳。

Analysis of Wind-resistant Stability on the Catwalk for Suspension Bridge

With attention focused on the inner force and displacement of catwalk exposed to the wind load,the mechanism of torsional collapse for catwalk was analyzed through nonlinear analysis performed by FEM method using sectional model tests results.The analysis indicates that air moment makes the base plate of catwalk faces positive angle of attack,and when the angle is large enough,the air lifting changes from downward to upward.Near the ultimate speed the stress of the catwalk rope begins to lack because of upward air lifting and the resisting force of catwalk is less than the air moment.