BFRP加固损伤混凝土梁裂缝间距与宽度计算

Crack spacing and width calculation of damaged concrete beams strengthened with BFRP sheet

为了准确计算玄武岩纤维布加固损伤混凝土梁的裂缝间距与宽度,为玄武岩纤维布加固损伤混凝土梁的设计与施工提供理论依据,设计了2组共计11片不同配筋率、不同纤维布加固量及不同加载方法的混凝土梁的试验方案。基于试验数据获取了各试验梁的裂缝形态分布及裂缝宽度数据,分析得出了未加固梁、1层纤维布加固梁、2层纤维布加固梁在不同初始荷载情况下的裂缝变化规律,并在此基础上给出了玄武岩纤维布加固损伤混凝土梁裂缝间距与宽度的修正计算公式。研究结果表明：与实测结果相比,修正后裂缝间距与裂缝宽度公式的计算误差分别为1.85%-6.5%和3.33%-15.7%,而规范公式计算误差分别为4.73%-13.2%和8.69%-22.2%,与规范公式相比,提出的玄武岩纤维布加固损伤混凝土梁裂缝间距与宽度修正计算公式具有更高的精确度。

In order to calculate crack＇s spacing and width of RC beam strengthened with BFRP accurately and provide theoretical basis for design and construction of RC beam strengthened with BFRP, experiment scheme was designed for two groups composed of eleven RC beams with different reinforcement ratios, different amount of strengthened BFRP sheets and different loading methods. Crack＇s morphology distribution and width of each beam was obtained according to experimental data. Crack＇s changing rules of unstrengthened beams, and strengthened beams with one layer and two layers BFRP sheets were analyzed under different conditions of pre-loading program. Modified formulas were presented for calculating crack＇s spacing and width of RC beam strengthened with BFRP. The results show that, compared with experimental results, crack spacing and width calculation errors of modified formulas are 1.85%-6.5% and 3.33%-15.7% respectively. However, their calculation errors of specification formula are 4. 73%-13. 2% and 8.69%-22. 2% respectively. It is concluded that crack spacing and width calculation formulas presented by this paper has higher accuracy than specification formula for damaged concrete beams strengthened with BFRP sheet. 2 tabs, 10 figs, 19 refs.