考虑加劲肋影响的钢箱梁剪滞效应研究

Study on Shear Lag Effect of Steel Box Girders Considering Influence of Stiffening Ribs

摘要:

以剪滞效应引起的变形作为广义位移，将钢箱各翼缘板的加劲肋面积折算到相应板件上，运用能量法建立了考虑加劲肋影响的钢箱梁剪滞效应微分方程和边界条件。以简支和悬臂的边界约束条件为例，推导了在均布荷载作用下简支和悬臂钢箱梁的剪滞效应解析解，并分析了考虑加劲肋影响的钢箱梁剪滞系数和挠曲线分布规律。研究结果表明：在均布荷载作用下，考虑加劲肋影响的钢箱梁剪滞解析解与有限元数值解吻合较好，证明了研究方法的正确性；在简支和悬臂约束条件下，钢箱梁剪滞系数纵向分布规律较悬殊；与初等梁挠度相比，均布荷载作用下考虑剪滞影响的简支钢箱梁跨中截面的挠度差值比为4.18%，悬臂钢箱梁自由端的挠度差值比为3.16%。

Abstract:

Taking the deformation caused by shear lag effect as the generalized displacement, the stiffening rib area of each flange plate of the steel box is converted to the corresponding plate, and the energy method is used to establish a differential equation and boundary conditions of the shear lag effect of the steel box girder considering the influence of stiffening ribs. Taking the simple-supported and cantilever boundary constraints as the examples, the analytical solutions for the shear lag effect of simple-supported and cantilever steel box girders are derived under the uniformly distributed load, and the distribution law of shear lag coefficient and deflection curve of steel box girders considering the influence of stiffening ribs is analyzed. The research results indicate that the shear lag analytical solution of steel box girders considering the influence of stiffening ribs is in good agreement with the finite element numerical solution under the uniformly distributed load, which verifies the correctness of the research method. There is a significant difference in the longitudinal distribution rule of shear lag coefficients under the simple-supported and cantilever constraints. Compared with the deflection of elementary beams, the deflection difference ratio of the mid span section of simple-supported steel box girders considering the shear lag effect is 4.18% under the uniformly distributed load, and the deflection difference ratio of the free end of cantilever steel box girders is 3.16%.