大跨度双链式悬索桥受力特性影响因素研究

为探索理想的大跨度双链式悬索桥布置形式,以某在建过江通道主桥(主跨1760 m的单跨简支钢箱梁悬索桥,加劲梁采用扁平流线型钢箱梁,梁宽31.5 m,梁高4.0 m)为工程背景,利用大跨度悬索桥几何非线性计算软件SNAS建立有限元模型,分析不同恒载分配系数μ和矢跨比λ对结构受力特性的影响。结果表明:随着μ减小,结构竖向非对称刚度提高,但主缆最大拉力增大;随着λ减小,结构竖向刚度提高,但塔底纵向弯矩与主缆最大拉力增大;当μ=0.3且λ=1/9.0对应的大跨度双链式悬索桥布置形式较优,结构具有较好的抵抗对称及非对称活载的竖向变形能力,且颤振临界风速最大。

Study of Influential Factors of Mechanical Property of Long-Span Suspension Bridge with Duplex-Cable System

To figure out the ideal layout of long-span suspension bridge with duplex-cable system,the main bridge of a river crossing that is under construction is taken as a case for the study.The bridge is a simply-supported steel box girder suspension bridge with a single span of 1760 m,the stiffening girder of which measures 31.5 m wide,comprising streamlined flat steel boxes of 4.0 m in depth.Finite element models were established by SNAS(a software that can do non-linear geometric calculation of long-span suspension bridge)to analyze the influence of partition coefficient of dead load μ and rise-to-span ratioλon the mechanical property of the structure.The results show that the decrease ofμcan lead to the improvement of the vertical asymmetrical stiffness of the structure,but the maximum tension of the main cable is also increased.With the decrease of λ,the vertical stiffness of the structure is improved,but the tower-base longitudinal bending moment and main cable maximum tension are increased.When theμand λ are set at 0.3 and 1/9.0,respectively,the long-span suspension bridge with duplex-cable system can obtain optimal structural configuration,with sufficient resistance of vertical deformation induced by symmetrical and asymmetrical live loads,and the maximum flutter critical wind velocity as well.