下承式拱桥风致抖振响应分析

Analysis on Buffeting Response of Through Arch Bridge

为研究风荷载对下承式拱桥抖振响应的影响,将风荷载分为4种荷载工况,采用时域分析的谐波合成法建立三维有限元模型,对某座下承式拱桥的位移响应进行对比研究。结果表明:在风荷载作用下拱肋的横向位移响应比桥面的横向位移大,拱肋脉动风对拱肋位移响应影响较大,但对桥面位移响应影响不明显;竖向脉动风对桥梁的横向位移响应影响不大,但对桥梁的竖向响应影响比较明显;横撑的存在有利于降低桥梁的位移响应。研究结果可供同类型的桥梁结构抗风设计参考。

For further research on the impacts of buffeting response of a through arch bridge subjected to the excitation of wind load, the wind load was divided into four cases and the harmonic wave superimposing method was used to build a three-dimensional finite element calculation model for studying those different levels of buffeting response of a through arch bridge. The results show that the transversal response of ribs is greater than that of the deck under the condition of wind load; the fluctuating wind of ribs has a great con- tribution to the response of ribs but little contribution to that of the deck; the vertical fluctuating wind has little contribution to the transversal response of the bridge but a great impact on its vertical response; the buffeting response of the bridge was reduced because of lateral brace. The results can provide reference for the wind-resistant design of the bridge structures of the same type.