BFRP筋增强螺旋箍筋区域约束混凝土梁的抗剪性能试验研究

Experimental study on shear performance of BFRP bars concrete beams with regional constraints

FRP筋可有效解决普通混凝土梁中的钢筋锈蚀问题,但是FRP筋混凝土梁的剪切破坏是脆性破坏,抗剪延性小。本文将区域约束技术应用到BFRP筋混凝土梁中,利用BFRP增强箍筋对剪压区混凝土进行约束。通过进行1根空白梁与4根约束梁的抗剪对比试验,研究约束螺旋箍筋的配箍率、剪跨比等因素对梁的极限荷载、破坏形态、延性的影响规律。研究显示在剪压区采用区域约束箍筋后,梁的抗剪延性得到明显改善,并且改变了梁的破坏形态,抗剪承载力随着剪跨比的提高而下降。

FRP bars can effectively solve the corrosion problem of steel reinforcement in ordinary concrete beams, but the shear failure of FRP-reinforced concrete beam is brittle failure and the shear ductility is small. In this paper, the regional restraint technology is applied to BFRP-reinforced concrete beams, and BFRP-reinforced stirrups are used to restrain the concrete in the shear compression zone. Through the shear comparative test of one blank beam and four restrained beams, the influence laws of spiral stirrup ratio and shear span ratio of restrained spiral stirrups on the ultimate load, failure mode and ductility of the beam are studied. The research shows that the shear ductility of the beam analyzed by equivalent energy method and displacement ductility coefficient method has been significantly improved, and the addition of regional confined stirrups changes the failure mode of the beam, and the shear bearing capacity decreases with the increase of shear span ratio.