CFRP加固高强钢筋混凝土梁抗剪承载力计算

Calculation of shear capacity of high strength reinforced concrete beams bonded with CFRP

为深入探讨高强混凝土结构用碳纤维布(简称CFRP)增强系列问题,对基于碳纤维布拉断的高强钢筋混凝土加固梁进行了抗剪性能试验研究,考虑了加固量、加固形式、剪跨比、预损伤程度、配箍率等参数的影响.试验结果表明,经碳纤维布加固的高强混凝土梁抗剪承载力提高较多,加固效果明显;预损伤对加固梁的抗剪承载力影响不大;剪跨比、加固量综合起来影响着碳纤维布的受力程度,从而影响到碳纤维布的有效应变,最终决定了试验梁的抗剪承载力.基于有效应变模型,提出了与试验结果相吻合的碳纤维布抗剪承载力计算方法,并结合我国碳纤维布加固混凝土结构规程,提出了高强钢筋混凝土梁用碳纤维布进行抗剪加固的设计方法.

In-depth experimental studies on the shear performances of high strength RC beams bonded with CFRP were carried out, in which numerous influencing factors were properly considered, including the amount of CFRP sheets in use, the reinforcement ways, the shear span ratio, the damage degree and the shear reinforcement ratio. The results indicate that the shear capacities of the repaired beams are obviously increased. Damages in advance have little influences on the shear capacities of the beams. Shear span ratio and the shear reinforcement amount of CFRP sheets are the two important factors impacting the effective strain of CFRP strips and thus finally determine the shear capacities. Based on the effective strain model, a calculational expression of shear capacity is established which predicts identical results with the experimental ones. Combined with the national regulations in concrete structures strengthened with CFRP, design proposal of high strength RC beams bonded with CFRP for shear reinforcement is finally derived.