脱空对上承式钢管混凝土拱桥整体稳定性能的影响

Analysis on the Influence of Disengaging on the Global Stability of Concrete-filled Steel Tube Deck Arch Bridge

以正在建设的西溪河双线铁路大桥为背景,建立了该拱桥的有限元模型,在线弹性和材料几何非线性基础上分析了脱空位置、内倾角、脱空率对拱桥第一类与第二类稳定性的影响.研究表明:随着拱肋脱空位置的改变,拱桥的稳定性系数也会随之变化,且对拱桥危害较大的是拱脚脱空;内倾角的合理设置能提高拱桥的横向刚度增加其稳定性;核心混凝土套箍作用的失效是引起钢管混凝土拱桥稳定性下降的主要因素,且应避免拱肋截面发生严重损失.

Against the background of the double-line railway bridge over XiXi River that is under construction,this paper established the finite element model of the arch bridge. Based on the linear elasticity and the material and geometric nonlinearity, the paper analyzed the influence of the disengaging position,leaning angle and the disengaging rate on the first and second types of stability of the arch bridge. The research shows that：with the change of the disengaging position of the arch rib, the global stability coefficient of the arch bridge would also change, and the disengaging of arch springing would have great harm to the arch bridge ;the reasonable setting of the leaning angle could improve the effective lateral rigidity of the arch bridge and increase its stability;the failure of hoopiug effect of the core concrete was the major factor to cause stability decline of the arch bridge. Moreover, serious section loss of the arch rib should be avoided.