CFRP布加固钢筋混凝土短梁短期荷载下裂缝宽度计算方法

Calculating method of crack resistance moment and crack width of reinforced concrete short beams strengthened with CFRP sheets under short-term loading

根据碳纤维(carbon fiber reinforced polymer,CFRP)布加固钢筋混凝土短梁的开裂弯矩和混凝土抗拉强度的试验实测值,计算CFRP布加固梁的截面抵抗矩塑性系数,给出CFRP布加固钢筋混凝土短梁抗裂弯矩计算公式。另外,采用钢筋混凝土裂缝理论,根据实测的CFRP布加固钢筋混凝土短梁的平均裂缝间距数据,提出考虑CFRP布加固和跨高比影响的CFRP布加固钢筋混凝土短梁在正常使用阶段的平均裂缝间距、钢筋应力及钢筋应力不均匀系数的计算公式。在此基础上,参照普通钢筋混凝土梁的裂缝宽度计算方法,根据试验实测的裂缝宽度数据,给出了短期荷载作用下与普通钢筋混凝土梁裂缝宽度计算公式相衔接的CFRP加固钢筋混凝土短梁的裂缝宽度计算公式。

Based on the measured values of cracking moment and tensile strength of reinforced concrete short beams(RCSB)strengthened with CFRP sheets,the plastic coefficient of section resistance moment of RCSB strengthened with CFRP sheets is calculated,and the formula for calculating cracking moment of RCSB strengthened with CFRP sheets is given.In addition,based on the crack theory of reinforced concrete and the measured average crack spacing data of RCSB strengthened with CFRP sheets,the formulas for calculating the average crack spacing,reinforcement stress and stress non-uniformity coefficient of RCSB strengthened with CFRP sheets considering the influence of CFRP sheet and span-height ratio are proposed.On this basis,referring to the calculation method of crack width of ordinary reinforced concrete beams,and based on the measured crack width data,the calculation formula of crack width of RCSB strengthened by CFRP under short-term load is proposed,which is connected with the calculation formula of crack width of ordinary reinforced concrete beams.