FRP筋混凝土梁正截面受弯承载力模型分析

Analysis on the flexural capacity model of FRP-reinforced concrete beams

结合国内外328组FRP筋混凝土梁受弯试验数据,系统分析了我国规范(GB 50608-2010)、美国规范(ACI 440.1R-15)、加拿大规范(ISIS manual 2007)和意大利规范(CNR-DT 203/2006)的承载力计算模型,对比了各国规范计算结果的准确性和离散程度.通过对受压破坏试件参数ρ_f/ρ_(fb)和c_b/x_(exp)进行回归分析,建立了等效矩形受压区高度x的经验公式,改进了受压破坏FRP筋梁承载力计算公式,并给出了使计算结果具有95%保证率的强度修正系数.结果表明:在ρ_f<ρ_(fb)和ρ_(fb)≤ρ_f<1.5ρ_(fb)两种情况下,各国规范计算值与试验值吻合良好;当1.5ρ_(fb)≤ρ_f时,各国规范计算值均偏保守.与以上规范计算公式相比,该文建议公式的计算值与试验值更为接近.

Collected and analyzed are 328 testing results of flexural capacity of FRP-reinforced concrete beams.The results were employed to assess the accuracy and dispersion degree of the current design formulas in GB 50608,ACI 440.1R,ISIS manual and CNR-DT 203.Regression analysis ofρf/ρfb and cb/xexp for specimens controlled by compression failure was carried out and the formula of depth of equivalent rectangular stress block x was obtained.The equation of flexural capacity of FRP-reinforced concrete beams controlled by compression failure was revised and the strength correction coefficient with 95%guarantee rate was proposed.The results showed that whenρf<1.5ρfb,the calculation results agreed well with the test results;and when 1.5ρfb≤ρf,however,the average predictions by specifications were all higher than test values by more than 20%.Compared with the standards,the proposed formulas yield estimations closer than the test results.