基于等效截面惯性矩的钢筋混凝土梁抗弯刚度计算方法

Calculation Method of Flexural Stiffness of Reinforced Concrete Beams Based on Equivalent Cross-sectional Inertia Moment

基于等效截面惯性矩概念,结合钢筋混凝土梁荷载-挠度曲线呈3阶段变化的特征,建立了钢筋混凝土梁在正截面开裂前和开裂后至纵向受拉钢筋屈服前的2阶段与作用弯矩相关的抗弯刚度计算公式.以纵向受拉钢筋配筋率和混凝土强度等级为变化参数,对12根钢筋混凝土梁进行受弯性能荷载试验.通过对比分析试验梁抗弯刚度的实测值与计算值,验证了所提计算方法的科学性和实用性.

In view of simplifying the calculation of flexural stiffness of reinforced concrete beam,based on the concept of the equivalent cross-sectional inertia moment and the characteristics of loading vs deflection curves of reinforced concrete beams changing as three stages,a formulas of flexural stiffness related to the loading moment of reinforced concrete beam in the former two stages,namely,before the cracking of normal-cross sectional concrete and before the yield of longitudinal rebar,is established. Taking the ratio of longitudinal tensile rebar and the strength grade of concrete as the variable parameters,the flexural behaviors of 12 reinforced concrete beams were studied in test,and the results show that the measured and calculated values are consistent. Therefore,the proposed calculation method is scientific and practical.