斜拉桥格构式钢塔极限承载力分析

Analysis of Ultimate Bearing Capacity of Lattice Steel Pylon of Cable⁃stayed Bridge

为研究斜拉桥格构式钢塔的受力特点及压弯极限承载力,以宝鸡市陆港格构式钢塔斜拉桥为工程背景,考虑几何非线性、材料非线性、几何缺陷、局部温度荷载等因素的影响,对桥塔极限承载力进行分析。结果表明:桥塔在达到极限承载力前,塔肢根部局部板件首先屈曲失稳,设计中对该类板件应重点补强;塔肢根部板件屈曲对主塔的水平位移影响显著;活载布置方式对桥塔承载力有影响,中跨满载时最不利;在塔肢根部一定范围内灌注混凝土形成钢箱混凝土结构,可以提高整体极限承载力;几何缺陷和局部温度荷载对格构式主塔极限承载力的影响较小,通过设定合理施工控制目标可以消除该影响。

In order to study the mechanical characteristics and ultimate bearing capacity of lattice steel pylon of cable-stayed bridge,taking Baoji Lugang lattice steel pylon cable-stayed bridge as the engineering background,considering the influence of geometric nonlinearity,material nonlinearity,geometric defects,local temperature load and other factors,the ultimate bearing capacity of the pylon was analyzed.The results show that before the pylon reaches its ultimate bearing capacity,the local plates at the root of the pylon limb first buckles and loses stability,and this kind of plates should be reinforced in the design.The buckling of the plate at the root of the pylon limb has a significant impact on the horizontal displacement of the main pylon.The arrangement of live load has influence on the bearing capacity of pylon,and full load of middle span is extremely unfavorable.The ultimate bearing capacity of steel box concrete structure can be improved by pouring concrete in a certain range at the root of pylon limb.Geometric defects and local temperature load have little influence on the ultimate bearing capacity of lattice main pylon,which can be eliminated by setting reasonable construction control objectives.