横撑对斜拉拱桥稳定性的影响

Effect of Lateral Brace on the Stability of Cable-stayed Concrete Filled Steel Tube Arch Bridge

采用有限元法分析了横撑对斜拉钢管混凝土拱桥整体稳定性的影响.以湘潭市湘江四大桥为例,采用线弹性特征值稳定的分析方法,探讨了横撑布置位置、布置形式以及横撑刚度对斜拉拱桥稳定性的影响.结果表明,横撑对斜拉拱桥稳定性的影响体现了和一般钢管混凝土拱桥相同的性质,对结构稳定性影响最大的是桥面上3/8处的K字撑.增加横撑的数量比增加横向刚度更能提高稳定性,在同等数量的横撑下,增加横撑刚度才能起比较大的作用.横撑刚度增大,稳定性提高;刚度减小,稳定性降低,因此,采取增大横撑弦管尺寸或者改变材料特性来提高横撑刚度的方法提高稳定性,效果不明显.

Using the finite element method, this paper computed and analyzed the stability of cable-stayed concrete filled steel tube arch bridge. Citing the Fourth Bridge over Xiangjiang River in Xiangtan City as an example and adopting the linear elastic characteristic value stable analysis method, the effect of the arrangement position, the arrangement form and the rigidity of the lateral brace on the stability of the bridge were discussed. The result indicated that the arrangement position of the lateral brace played the decisive role in the stability of the cable-stayed concrete filled steel tube arch bridge. The lateral brace lying 3/8 above the deck exerted the greatest impact on the structural stability. The number, rather than the rigidity of the lateral brace, was more likely to increase the stability, so the increase of the lateral brace rigidity played a greater role in the case of equal number of lateral brace. The greater the rigidity of the lateral braces, the higher the stability, and vice versa. Therefore, enlarging the lateral brace tube or changing the characteristics of materials was not an effective way to increase the stability of lateral brace.