有粘结预应力FRP筋混凝土梁正截面受弯承载力计算方法

Calculation Methods for Flexural Capacity of Normal Section of Concrete Beams Prestressed with Bonded FRP Tendons

国内外已有试验研究表明,有粘结预应力FRP筋混凝土梁的破坏模式包括界限破坏、受压破坏与受拉破坏三种。在我国现行规范中尚无关于预应力FRP筋混凝土梁的设计规定,在ACI440.4R-04规范中虽有相关的规定,但其针对的是截面受拉区仅配置预应力FRP筋的混凝土梁。对截面受拉区同时配置预应力FRP筋和非预应力钢筋、预应力FRP筋和非预应力FRP筋这两种混合配筋形式下的有粘结预应力FRP筋混凝土梁的正截面抗弯承载力计算方法进行了研究。基于受弯截面的极限状态分析,分别提出了三种破坏模式下正截面抗弯承载力的计算公式。为了验证公式,进行了6根有粘结预应力FRP筋混凝土梁的单调静力试验以及基于ANSYS软件的非线性有限元参数分析。应用建议公式对课题组及国外完成的48根有粘结预应力FRP筋混凝土梁的试验结果和6根梁的参数分析结果进行了计算与对比,计算值与试验结果和参数分析结果吻合较好。

The failure modes of concrete beams prestressed with bonded FRP tendons can be classified into three types： the balanced failure, compression-controlled failure and tension-controlled failure. At present, no design provisions for bonded FRP tendons are included in current Chinese codes. Some correlative provisions are involved in the ACI 440.4R-04 code, which only focus on the concrete beams with FRP tendons in the tension region. It presents studies on the calculation methods for flexural capacity of the concrete beams, reinforced with both FRP tendons and steel bars, or both prestressed and nonprestressed FRP reinforcements. The calculation formulas for flexural capacity are provided based on analysis of the ultimate statement of sections. Experimental studies on six concrete beams prestressed with bonded FRP tendons and nonlinear parametric analysis are carried out to verify the proposed formulas. The flexural capacity of existing forty-eight specimens and six parametric specimens is calculated by the proposed formulas. Comparisons show that the calculated values agree well with the experimental results and parametric analysis results.