为了给混合配筋(混合配置FRP与钢筋)混凝土梁的设计应用提供参考,对已有抗弯承载力计算公式进行了对比分析,并通过将理论值与试验值的对比,证明了各公式的精确性和有效性。通过改变混凝土强度、钢筋强度、FRP筋种类、混凝土极限压应变以及有效配筋率等参数,采用理论分析的方法讨论了限定纵筋最大拉应变对理论计算结果的影响。结果表明:已有混合配筋混凝土梁抗弯承载力计算公式均是基于平截面假定,根据截面内应变协调和力的平衡得出,均能很好地预测试验结果,误差较小;但限定纵筋最大拉应变后的理论值偏于安全,因此,推荐设计时采用限定纵筋最大拉应变的混合配筋混凝土梁抗弯承载力计算公式。
To provide a reference for the design and application of concrete beams reinforced with hybrid(FRP and steel)bars,comparative analyses among different existing calculation formulas for flexural strength were performed.The comparison between the theoretical results and experimental results verified the accuracies and validities of these formulas.The influences of allowable ultimate tensile strain of longitudinal reinforcement on the theoretical calculation results were discussed based on theoretical analysis by changing parameters including concrete strength,strength of steel bar, FRP type,ultimate compressive strain of concrete and effective reinforcement ratio.The results show that existing formulas in calculating flexural strength of concrete beams reinforced with hybrid bars are based on the plane section assumption and the strength can be obtained according to strain compatibility and force equilibrium inside the cross sections.The theoretical formulas can well predict the flexural strengths with small errors.However,the theoretical values are safer when the allowable ultimate tensile strain of longitudinal reinforcement is confined.Therefore,the theoretical formula in which the allowable ultimate tensile strain of longitudinal reinforcement is confined is recommended in the design.