玻璃纤维布加固钢筋混凝土梁正截面抗弯承载力计算

Calculation of flexural capacity of RC beams strengthened with GFRP sheets

通过14根玻璃纤维布加固的钢筋混凝土粱试验研究,证明经玻璃纤维布加固的钢筋混凝土粱抗弯承载力提高较多。加固效果明显。在试验的基础上对玻璃纤维布加固的钢筋混凝土梁正截面抗弯承载力计算方法进行了分析。根据不同的破坏模式提出了不同的极限状态计算公式,给出了最大和最小玻璃纤维布使用面积的计算方法。同时,根据试验结果和美国FRP加固设计规范提出了玻璃纤维布加固钢筋混凝土粱的相对界限受压区高度和设计极限拉应变。计算结果表明,本文建立的计算公式与试验值吻合较好,误差较小。

Fourteen RC beams strengthened with glass fiber reinforced polymer(GFRP) sheets were tested. The experimental results showed that the flexural strength of the repaired beams was increased. An analytical study concerning the flexural strengthening of RC beams with externally bonded GFRP sheets was conducted according to the experimental results of fourteen RC beams. Based on their different failure modes, the calculation formulas are given. Also, this paper advances the maximum GFRP area and minimum GFRP area to avoid brittle failure of RC beams strengthened with the externally bonded GFRP sheets. At the same time, the ratio of extreme depth x_m to the depth h_f and the designed ultimate strain of GFRP sheets are presented as well. The analytical model is shown to be in good agreement with the experimental results.