Experimental Investigation On Seismic Performance Of CFRP Reinforced Concrete Column With MRD

Carbon fiber-reinforced Polymer Bars(CFRP)have the characteristics of light weight,high strength,corrosion resistance,and high tensile strength,in addition,its stress-strain curve is linear elastic.These features make CFRP reinforced concrete column have high bearing capacity,satisfactory self-centering capacity,and greatly reduce the residual displacement of the structure.but its hysteresis curve is not full,the energy dissipation ability is bad.This puts forward a higher requirement on the energy dissipation capacity of CFRP reinforced concrete column.Magnetorheological damper(MRD)is a kind of excellent semi-active control devices,which have the characteristics of fast response speed,low energy consumption,adjustable output.In this paper,MRD is arranged on CFRP reinforced concrete column,which can be used to improve the energy dissipation capacity of the column,so as to develop the CFRP reinforced concrete column with high bearing capacity,low residual deformation and high energy dissipation ability.On the basis of the aim,this paper mainly studies the influence of MRD with different currents on the seismic performance and selfresetting performance of CFRP reinforced concrete column,and providesa new research idea for the joint use of MRD with CFRP reinforced concrete column.A low-cycle and reverse loading test was completed for 1 ordinary reinforced concrete column and 2 CFRP reinforced concrete columns with MRD(MRD-CFRP concrete column),This test mainlyanalyze the failure modes,hysteretic curves,skeleton curves,stiffness and strength degradation,energy dissipation capacity,residual deformation,lateral curve,crack propagation and reinforcement strain of the three concrete columns.The test results shows that:(1)The external MRD has changed the cracks development form of the CFRP reinforced concrete column and improved the characteristics of uneven crack development of ordinary reinforced concrete column.Compared with reinforced concrete column,MRD-CFRP concrete column has higher crack development height,wider distribution and and largar spacing.The larger the current of MRD,the wider the crack width and the more uniform the crack distribution.(2)the limits of the interlayer displacement angle of the three columns are all satisfied the request of 1/50 of technical specification for concrete structures of highrise buildings,the limit interlayer displacement angle of MRD-CFRP concrete columns is 1/20,which is 1.25 times that of reinforced concrete column.Moreover,the bearing capacity of MRD-CFRP concrete column is improved obviously,and the bigger the current of MRD,the higher the bearing capacity.(3)At the same displacement,the stiffness of ordinary reinforced concrete column is smaller than that of MRD-CFRP concrete column,and the greater the current of damper,the bigger the initial stiffness and the stiffness during loading of the column.The strength degradation coefficient of the three concrete columns is more than 0.96 and the bearing capacity is stable.(4)Turning off the power supply of the damper when the force is unloaded to zero,the residual deformation and residual cracks of the MRD-CFRP concrete column are effectively controlled.The residual deformation of CFRP150 is 67.14% smaller than that of reinforced concrete column,indicating that the CFRP reinforced concrete column installed with MRD has the good self-centering ability.(5)Compared with ordinary reinforced concrete,the energy dissipation capacity of the MRD-CFRP concrete column is significantly improved,and the cumulative energy dissipation can increase by up to 104.9%.The greater the current of the damper,the greater the contribution to the energy dissipation of CFRP reinforced concrete column.Setting MRD on CFRP reinforced concrete columns can meet the requirements of high energy dissipation capacity and low residual deformation of seismic structures.