计及剪切影响的RC梁的非线性分析

为提高钢筋混凝土RC梁的计算效率和精度,提出了一种基于梁截面弯矩-曲率关系的宏观有限元方法,可用于各种跨高比RC梁的材料非线性分析。首先假定了混凝土和钢筋的非线性应力-应变关系,然后引入经过修正的Rodriguez截面模型,根据边界顶点把截面划分成若干梯形单元,利用quasi-Newton法求解由两个变量耦合而成的截面非线性平衡方程,由此建立RC截面的弯矩-曲率关系。在此基础上利用Timoshenko梁弯曲理论建立考虑横向剪切变形影响的RC梁的有限元分析模型。通过对试验梁的分析对比验证了所提出的分析方法的适用性。

Nonlinear analysis of RC beams considering shear effect

To improve the computational efficiency and accuracy of reinforced concrete RC beams,a macroscopic finite element method based on the moment-curvature relationship of beam section was presented,which is capable of performing the material nonlinear analysis of RC beams with various span-depth ratios.Nonlinear stress-strain relationships for concrete and steel were assumed firstly,and then a section analysis model suggested by Rodriguez was revised and introduced,in which the cross section was divided into several trapezoids according to boundary vertices.The quasi-Newton algorithm was used to solve the nonlinear equilibrium equations coupled with two variables.Thereby,the moment-curvature relationship of RC section was established.On this basis,Timoshenko beam flexural theory was utilized to develop the finite element analysis model for RC beams considering the effect of transverse shear deformation.Two beam specimens were analyzed using the proposed analysis method,and the reliability and validity of the proposed model is verified by comparing the analytical predictions with the experimental results.