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为了研究不同层数玄武岩纤维布(basalt fiber reinforced polymer,BFRP)对加固钢筋混凝土梁抗弯性能的影响,使用分离式油压千斤顶对梁进行三分点加载试验。分别观测梁底部粘贴1层、2层和3层BFRP时加固梁的破坏形态、开裂荷载、屈服荷载、极限荷载及以上荷载对应的跨中挠度,并与基准梁进行了对比分析。试验结果表明:随着BFRP粘贴层数的增加,梁的破坏形态发生了改变,主裂缝数量减少,开裂荷载、屈服荷载和极限荷载均有不同程度的提高,其中极限荷载分别提高了7.92%(1层)、23.66%(2层)和29.31%(3层),对应跨中挠度也分别降低了14.54%、26.65%和28.81%;粘贴1~2层BFRP时,梁的延性系数有所增大,而粘贴3层BFRP时,延性系数减小;弯曲裂缝的产生和扩展是引起BFRP发生破坏的主要原因;梁的抗弯性能并不与BFRP层数成比例增加,综合来看,采用2层BFRP加固的梁,不仅抗弯承载力和延性得到了较大提高,跨中挠度也大幅下降,具有良好的经济性。
In order to study the effect of different layers of basalt fiber reinforced polymer (BFRP) on the flexural behavior of reinforced concrete beams, a split hydraulic jack was used to load the beam for three points. The failure mode, cracking load, yield load, ultimate load and corresponding mid-span deflection of reinforced beam were observed respectively when the first, second and third layers of BFRP were attached to the bottom of the beam, and compared with the reference beam. The experimental results show that with the increase of the number of BFRP layers, the failure morphology of the beam changes, the number of the main cracks decreases, the cracking load, yield load and ultimate load increase in varying degrees, and the ultimate load increases by 7.92% 1 layer), 23.66% (2 layers) and 29.31% (3 layers) respectively, and the corresponding mid-span deflections also decreased by 14.54%, 26.65% and 28.81% respectively. The ductility coefficient decreases when the three layers of BFRP are pasted; the generation and expansion of the bending cracks are the main causes of the destruction of BFRP; the bending performance of beams does not increase proportionally with the number of layers of BFRP. On the whole, Beams reinforced with layers of BFRP have not only improved the flexural capacity and ductility but also reduced the midspan deflection significantly, which has good economy.