横撑及桥面系对钢管混凝土拱桥动力响应的影响分析

横撑和桥面系作为钢管混凝土拱桥的重要组成部分对结构整体动力响应会产生很大的影响。以茅草街大桥为例,建立了中承式钢管混凝土拱桥不同横撑和桥面系布置形式的有限元模型,采用三向地震波同时输入的形式,得到6种工况在相同地震波作用下的不同动力响应,提取出拱肋的弯矩和位移包络图,并对面内弯矩、面外弯矩、竖向位移、横桥向位移进行了比较和分析。结果表明,桥面系对拱肋的响应影响很大;拱肋与桥面系结合处位移、内力均较大,在设计中应予以关注;在保证横向刚度的前提下,横撑需进行优化布置,以使得拱桥动力响应更加合理安全。

Analysis on Dynamic Response of CFST Arch Bridges Affected by Cross Beams and Decks

As the important components of CFST arch bridges,the cross beams and bridge decks affect the bridges' dynamic response magnificently.Based on the Maocaojie Bridge,the FEM models of half-through CFST arch bridges with different arrangements of cross beams and bridge decks were built.The different seismic responses of six operating conditions were calculated with three dimensional earthquake waves input.The internal forces and displacement envelope diagrams of arch ribs were extracted,compared and analyzed in situations of in-plane moment,out-plane moment,vertical displacement and transverse displacement.The result shows that(1) the bridge decks affect the response of arch rib greatly;(2) the joint section between arch rib and bridge deck should be designed carefully because of its large displacement and internal force;(3) the cross beams should be optimized to safety the arch bridge dynamic response considering lateral rigidity.