考虑剪力滞效应影响的箱形梁弯曲剪应力分析

Analysis on Bending Shear Stress of Box Girder Considering Shear Lag Effect

为了研究剪力滞效应对箱形梁弯曲剪应力的影响,运用微元体平衡微分方程和位移协调条件建立了考虑剪力滞效应影响的箱梁弯曲剪应力计算方法,结合初等梁理论和剪力滞翘曲解析理论导出了简支箱梁集中荷载作用下的弯曲剪应力解析解.分析表明,翘曲剪应力沿横截面流向与初等梁流向相反,翘曲剪应力对初等梁剪应力具有一定的削弱作用;翘曲剪应力在初等梁剪应力中所占比重较小,l/4截面处翘曲剪应力在初等梁中所占比重最大为2.62%,其影响可忽略不计.

In order to study the effect of shear lag on bending shear stress of box girder,the computation method of bending shear stress of box girder considering shear lag effect was established by using equilibrium differential equations of Micro-element and the condition of displacement coordination.The analytical solution of bending shear stress of simply supported box girder under concentrated load was derived by combining the theory of elementary beam with shear lag warping.The example shows that the warping shear stress is almost opposite to the elementary beam along the cross section.The warping shear stress has a certain weakening effect on the shear stress of the elementary beam.The proportion of warping shear stress in primary beam shear stress is small,and the maximum proportion is 2.62% at the l/4 section,and its influence can be ignored.