载荷横向变位对箱梁剪力滞效应的影响

THE SHEAR LAG EFFECT OF BOX BEAMS WITH VARYING LATERAL LOADING LOCATIONS 1)

  • 摘要: 对箱梁各翼板(顶板、悬臂板、底板)分设不同剪力滞广义纵向位移,其横向分布均取二次抛物线形式,并引入载荷横向位置参数η,以分析载荷横向变位对剪力滞效应的影响.运用能量变分原理,建立剪力滞控制微分方程,求解了简支梁和悬臂梁在均布载荷作用下的控制微分方程的解.算例分析表明:载荷横向变位改变直接承受载荷的翼板的正负剪力滞特性,对非直接承载翼板只改变其应力幅度;箱梁横向框架效应对直接承载翼板纵向应力的贡献远远大于剪切变形.与块体有限元分析结果较吻合,表明该算法能较准确分析载荷横向变位作用下箱梁剪力滞的变化规律.

     

    Abstract: The box girder's wing plates(including the roof, the cantilever plate and the bottom floor) are divided into parts of different generalized longitudinal displacements of shear lag. Taking a parabola as the transverse distribution form for each wing plate and introducing lateral position parameters 'η', the shear lag effect is analyzed for cases with varying lateral loading locations. A control differential equation is built for the shear lag effect of the box beam and it is solved for the simply supported beam and the cantilever beam under uniform load by using the energy variation principle. Examples show that the varying lateral loading locations affect the positive and negative shear lag characteristics of the loading wing plate and the magnitude of the stress in the non-load plate. The lateral framing effect makes much greater contribution than the shear deformation for the longitudinal stress. The result is consistent with the analytic result of the block finite element model, which shows that the algorithm can accurately analyze the shear lag effect of the box girder for cases with varying lateral loading locations.

     

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