混凝土短梁斜向开裂后的有效剪切刚度与变形

Effective shear stiffness and deformation of concrete short beams after diagonal cracking

为了研究钢筋混凝土短梁有效剪切刚度的计算,根据以往试验资料分析了短梁开裂后的斜裂缝形态及其发展,探讨了此阶段的剪切刚度变化规律;在变角桁架模型的基础上运用内插法得出混凝土从斜向开裂至0.8F_u阶段的有效剪切刚度,进而计算出相应的剪切变形和挠度,并与试验结果进行比较;此外,将计算值与其它三种方法的计算值进行了对比分析.结果表明,按本方法计算出的挠度值与试验值符合较好;相对于其它方法,本方法能较好地预测短梁自斜向开裂至0.8F_u阶段的变形,且提高了计算精度.

To study the calculation of effective shear stiffness of reinforced concrete short beam,the shapes and developments of the diagonal crack after the short beam cracking were analyzed according to the previous test data,and the variation of shear stiffness in this stage was discussed.Based on the variable angle truss model,the effective shear stiffness of short beam from diagonal cracking to 0.8F_u was obtained by using the interpolation.Then the corressponding shear deformation and deflection were calculated,and compared with experimental results.In addition,a contrastive analysis of the calculated values of this method and other three methods were carried out.The results show that the deflection values calculated by this method are in good agreement with the experimental values.Compared with others,the proposed approach can better predict the deflections of the short beam from diagonal cracking to 0.8F_u,and improve the accuracy of calculation.