带翼缘截面混凝土受压区等效应力图系数研究

Study on Equivalent Stress Diagram Coefficient of Concrete Compression Zone with Flange Section

针对带翼缘截面混凝土受压区等效应力图系数α和β计算方法空缺的问题,以截面平衡为建立基本方程的唯一条件,得到了考虑截面几何参数和材料参数的带翼缘截面等效应力图系数的解析解,分析了截面几何参数对等效应力图系数的影响。为提高解析公式的可应用性,对解析解进行了再拟合处理,得到了拟合度较高的α和β简化计算公式,并给出了常用截面等效应力图系数的建议值。结果表明:等效应力图系数α随梁腹板宽度与翼缘板宽度的比值b/b_(f)的增大而减小,随翼缘板厚度与截面有效高度的比值h_(f)/h_(0)的增大而增大,总体呈曲面变化特征;β随b/b_(f)的增大而增大,随h_(f)/h_(0)的变化呈曲线变化,总体呈微扭曲面变化特征;推荐的简化公式精确度较高,可直接应用于带翼缘混凝土截面的分析计算中,等效应力图系数建议值可为混凝土规范的修订提供科学支撑。

Aiming at the problem that the calculation method of the equivalent stress diagram coefficientαandβof concrete compression zone with flange section is vacant,the analytical solutions of the equivalent stress diagram coefficient of the flange section considering the geometric parameters and material parameters of the section were obtained by taking the section balance as the only condition for establishing the basic equation,and the influence of the geometric parameters on the equivalent stress diagram coefficient was analyzed.In order to improve the applicability of the analytical formula,the analytical solution was refitted,and the simplified calculation formulas ofαandβwith high fitting degree were obtained,and the recommended values of the equivalent stress diagram coefficients of the commonly used cross-section were given.The results show that the coefficientαdecreases with the increase of the ratio of beam web width to flange plate width b/b_(f),and increases with the increase of the ratio of flange plate thickness to section effective depth h_(f)/h_(0),showing the characteristics of surface variation.βincreases with the increase of b/b_(f),and shows a curve change with the change of h_(f)/h_(0),showing the characteristics of slightly distorted surface.The recommended simplified formula has high accuracy and can be directly applied to the analysis and calculation of concrete section with flange.The recommended value of equivalent stress diagram coefficient can provide scientific support for the revision of concrete specification.