无腹筋BFRP筋混凝土深梁受剪性能研究

STUDY ON SHEAR RESISTANCE OF BFRP REINFORCED CONCRETE DEEP BEAMS WITHOUT STIRRUPS

在对称集中荷载作用下,对7根无腹筋BFRP筋混凝土深梁进行受剪试验,分析了构件的裂缝发展、破坏形态及不同剪跨比、BFRP筋配筋率、玄武岩纤维体积掺率对构件跨中挠度、开裂荷载和极限荷载的影响。试验结果表明:各试验梁均发生剪切破坏;相同荷载作用下,跨中挠度随着剪跨比的增大而增大,随着配筋率及玄武岩纤维体积掺率的增大而减小;开裂荷载与极限荷载均随着剪跨比的增大而减小,随着配筋率及玄武岩纤维体积掺率的增大而增大。参照相关规范对试验梁抗剪承载力进行计算,研究结果表明美国ACI 440. 1R-06规范计算值与试验值比较吻合,加拿大CSA. S 806-12规范稳定性较好,中国GB 50608—10规范相对保守,建议采用美国ACI440. 1R-06规范对无腹筋BFRP筋混凝土深梁进行抗剪承载力计算。

In order to study the influence of different shear span ratio,reinforcement ratio and basalt fiber volume fraction on the deflection,cracking load and ultimate bearing capacity,7 basalt fiber reinforced polymer(BFRP)reinforced concrete deep beams without stirrups were investigated,and the crack development and failure mode were analyzed.The research results can be obtained as follows.The failure mode of all beams is shear failure;Under the same load,the mid-span deflection of specimen can be improved by the increase of shear span ratio,while will be reduced by the increase of BFRP reinforcement ratio and basalt fiber volume fraction.The cracking load and ultimate load of beams are weakened with the shear span ratio increases,and will be increased with the increase of longitudinal reinforcement ratio and basalt fiber volume fraction.Calculation of shear capacity of test beams was performed by reference to relevant specifications,and it is found that shear design equations of the ACI 440.1R-06 code were better predictions,the predications of CSA.S 806-12 code were more stable and the GB 50608-10 were relatively conservative.The ACI440.1R-06 code is suggested to be used to calculate the shear capacity of BFRP reinforced concrete deep beams without stirrups.