铁路大跨度连续梁拱组合桥结构参数研究

为了解结构设计参数对铁路大跨度连续梁-拱组合桥受力特性的影响,进而对今后同类桥梁设计提供引导作用,以兰渝线广元嘉陵江特大桥为工程背景,研究矢跨比、拱轴线形状、拱梁刚度比这3个设计参数对桥梁结构力学特性的影响。分析结果表明:矢跨比对拱肋轴力和拱脚、主梁中跨弯矩影响显著,取值在1/4~1/5时较为合理;1.6次抛物线、2.4次抛物线及圆弧线作为拱轴线时,拱脚截面弯矩过大,2次抛物线或悬链线作为此类桥型的拱轴线较为合理;拱梁刚度比对结构轴力影响较小,对拱肋弯矩影响较大,随拱梁刚度比的增大,拱肋分担的弯矩显著提高。

Research on Design Parameters of Railway Long-span Continuous Beam and Arch Bridge

In order to understand the impact of the structural design parameters on the stress characteristics of railway long-span continuous beam and arch bridge and to guide the future design of the similar bridges,the Guangyuan Jialing River Bridge on Lanzhou-Chongqing railway it referenced to study the impact of the ratio of rise to span,the arch axis shape and the arch beam stiffness ratio on the mechanical characteristics of the bridge. Analysis results indicate remarkable impact of the ratio of rise to span on the axial force of rib arch and the arch of the foot and the girder mid-span bending moment,and the value between 1 /4 to 1 /5 is more reasonable. When 1. 6 parabolic,2. 4 parabolic and circular arc are taken as the arch axis,the arch foot section bending moment is too big and the second parabola and the catenary are more feasible to be taken as the arch axis of this kind of bridge. The arch beam stiffness ratio has little impact on the structure of the axial force,but more on arch rib bending moment. As the arch beam stiffness ratio increases,the bending moment of the arch rib is significantly improved.