BFRP布加固钢筋混凝土圆柱的抗震性能研究

Research on seismic performance of BFRP-confined reinforced circular concrete columns

基于4根玄武岩纤维布(Basalt Fiber Reinforced Plastic,BFRP)约束钢筋混凝土圆柱和2根未加固柱的低周反复侧向加载试验,研究了试件的受力性能和机理,对比分析了剪跨比、轴压比和加固方式对柱变形性能的影响.利用ABAQUS软件对试件进行非线性有限元分析,且验证了模型的有效性.在此基础上,以BFRP包裹层数、纵筋配筋率和箍筋配箍率为变化参数,重点研究了各参数对加固柱抗震变形能力的影响.结果表明:随着剪跨比的减小及轴压比的增大,加固柱延性性能明显降低,且BFRP对低剪跨比加固柱变形能力的提高效果最好;等BFRP加固量下全包较条带加固柱抗震性能略优;加固柱的变形能力随着包裹层数得提高而增强,但层数超过4层后,BFRP对柱的加固效果不再明显;当加固柱的纵筋配筋率增至3.2%时,其延性性能变化趋势由上升转为下降;而增加箍筋配箍率则可显著改善加固柱的极限位移.

The low cyclic lateral loading tests were conducted on four basalt fiber reinforced plastic(BFRP)confined circular columns and two unconfined columns.The mechanical behavior and mechanism of specimens were investigated,and the influences on the deformation performance were analyzed by the parameters of shear span ratio,axial compression ratio and confining method.Nonlinear finite element analysis of the specimens was carried out by ABAQUS software,and the feasibility of models was verified.Then,the influences of BFRP layer,longitudinal reinforcement ratio and stirrup ratio on the seismic deformation capacity of columns were studied.Results show that with the reduction of shear span ratio and increment of axial compression ratio,the ductility of confined columns drops significantly,and the BFRP has the best effect on improving the deformation capacity of the columns reinforced with low shear-span ratio.With the same amount of BFRP,the seismic behavior of all wrapped columns is slightly better than that of partial wrapped columns.Moreover,the column deformation capacity is improved with the increase of BFRP layer,but the BFRP confinement is not obvious with more than four layers.When the longitudinal reinforcement ratio of columns reaches 3.2%,the ductility trend changes from rise to drop,while increasing the stirrup ratio can significantly improve the ultimate displacement of reinforced columns.