Experimental Study On Compressive Performance Of Concrete Columns Reinforced By GFRP Bars

It is the most effective way to solve the corrosion problem to use Fiber Reinforced Plastic(FRP)bar instead of steel bar in concrete structure.The performance of concrete columns reinforced by GFRP bars is different from that of reinforced concrete(RC)column and needs further study.Based on the study of bond performance of GFRP bars,the evolution of bond strength,bond stiffness,bond-slip curve and residual bond performance is studied by drawing test.On this basis,the axial compression and eccentric compression behavior of concrete column reinforced with GFRP bars are studied experimentally and related analysis is carried out.The variation of failure model,ultimate bearing capacity and load-strain relationship of concrete columns reinforced by GFRP bars under different reinforcement methods is revealed.The main conclusions are as follows:(1)The variation of the rising and descending sections of the bond-slip curve between GFRP bars and mortar basically follows the mBPE model,and Gaussian function expression is proposed for the law of residual segment curve based on the function fitting,The failure of the interface between GFRP bars and mortar is different from that of reinforced concrete.(2)Full GFRP reinforced concrete column have no obvious signs of failure,which is brittle failure.But the mixed reinforced concrete column and the RC column both have failure sign.The axial ultimate bearing capacity of full GFRP reinforced columns is about 22.70% lower than that of RC columns.For the mixed reinforcement columns,when the stirrups are steel bars,the ultimate bearing capacity is about 1.16% higher than that of RC columns.When stirrups are GFRP bars,the ultimate bearing capacity of reinforced concrete columns is about 10.83% lower than that of RC columns.(3)The eccentricity has a significant effect on the ultimate bearing capacity and lateral deformation of the reinforced column with GFRP bars and steel bars,when the other parameters are same,the greater the eccentricity,the smaller the ultimate bearing capacity and the greater the lateral deformation in the column.And eccentricity has a remarkable effect on the surface strain of concrete.Under the same load level and other parameters,the greater the eccentricity,the greater the strain on the concrete surface of tensile area and compressive area.