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目前结构施工仿真计算多采用平面杆系有限元模型,而桥面板剪力滞后效应会使平面杆系模型分析结果产生误差。该文考虑混凝土的长期性能,引入翘曲位移形状函数与强度函数,描述结合梁剪力滞后效应。利用最小势能原理,以整体竖向挠度和翘曲强度函数为未知函数,推导出结合梁微段平衡微分方程及边界条件方程,引入“附加弯矩”描述剪力滞后效应对结构变形的影响;可根据具体结构形式的边界条件,得到结合梁模型变形的解析解。通过算例验证了模型和解析解的正确性,并分析了结合梁剪力滞后效应的时效性。考虑承受均布荷载的固端梁,采用现行规范有效宽度计算的结果介于弹性与粘弹性结果之间。利用该文计算方法,可以减小剪力滞后效应对杆系模型计算结果带来的误差。
At present, the finite element model of plane bar system is mostly used in the structural construction simulation calculation, while the shear lag effect of the bridge slab makes the analysis result of plane bar system model error. In this paper, considering the long-term performance of concrete, warping displacement shape function and strength function are introduced to describe the shear lag effect of the composite beam. By using the principle of minimum potential energy, the integral vertical differential equations and the buckling strength function are taken as unknown functions, the differential equations and the boundary conditions for the microstructure of the bond beam are deduced. The “additional bending moment” is introduced to describe the effect of shear lag on the structural deformation The analytical solution of the deformation of the bonded beam model can be obtained according to the boundary conditions of the concrete structure. The correctness of the model and analytic solution are verified by an example, and the timeliness of shear lag effect is analyzed. Considering the fixed-end girder subjected to uniform load, the result calculated by the effective width of the current code is between the elastic and viscoelasticity results. Using this method, the error caused by the shear lag effect on the calculation results of the bar model can be reduced.