预应力FRP加固混凝土梁的变形性能研究

Study on the Ductility of RC Beams Strengthened with Prestressed FRP Sheets

结合试验结果对预应力FRP加固混凝土梁的变形性能进行了理论研究。推导了考虑预应力损失的截面屈服曲率、极限曲率和相应的屈服弯矩、极限弯矩表达式;计算了试件在不同预应力度、不同FRP补强率、不同纵筋含钢率情况下的截面曲率延性系数μφ,并进行了相关因素分析;简化M-φ曲线为两折线模型。分析结果表明:预应力度、预应力FRP补强率、纵向受拉钢筋配筋率ρ和纵向受压钢筋配筋率ρ′对截面曲率延性都有影响,其中纵向受拉钢筋配筋率ρ和纵向受压钢筋配筋率ρ′对截面曲率延性影响较显著。推导的理论计算公式和试验结果吻合较好。

A theoretical study of deformation behavior of RC beams strengthened with prestressed FRP sheets was carried out based on tests results. Formulas were developed for computing the section yield curvature, ultimate curvature, yield moment and ultimate moment. The curvature ductility coefficient μφ of section was computed considering such factors as different prestress degree, the amount of FRP sheets and the longitudinal steel ratio. The M-φ curve was simplified as two-fold line model. The results show that the prestress degree, the amount of FRP sheets, the longitudinal tensile steel ratio ρ and the longitudinal compressive steel ratio ρ all have influence on the section curvature ductility which is greatly influenced by ρ and ρ. The results from the formulas generally agree with those from the experiment.