有粘结预应力FRP筋混凝土梁挠度的计算方法

与预应力钢筋相比,FRP筋的弹性模量较低、粘结性能稍差,因此有粘结预应力FRP筋混凝土梁的挠度比相应的预应力钢筋混凝土梁的大。在考虑预应力FRP筋等效的基础上,对我国现行《混凝土结构设计规范》中适用于普通预应力钢筋混凝土梁短期刚度的计算公式进行了修正。应用该修正公式和ACI 440.4R—04规范中的计算公式对国内外31根有粘结预应力FRP筋混凝土梁试件与6根参数分析试件的挠度进行了计算。对比表明,按修正公式计算的挠度值与试验结果和参数分析结果吻合更好。

Calculation Methods for Deflections of Concrete Beams Prestressed with Bonded FRP Tendons

Compared with the prestressing steel bars,FRP tendons exhibit the lower elastic modulus and worse bond behaviors between concrete.So the deflections of concrete beams prestressed with bonded FRP tendons are expected to be larger than those of the steel bars cases.The calculation methods of short-term stiffness of flexural concrete members reinforced with steel bars in current Chinese design code for concrete structures are modified taking account of the equivalent of FRP tendons.The deflections of existing thirty-one specimens and six parametric specimens are calculated based on the modified formulas and the correlative provisions proposed in ACI 440.4R-04 codes.Comparisons show that the calculated values given by the modified formulas agree well with the experimental results.