Seismic Performance Analysis Of RC Columns Strengthened With Prestressed Steel Strands And High-performance Mortar

As a new type of seismic reinforcement method developed in recent years,prestressed steel strand-high-performance mortar reinforcement has gradually received widespread attention in engineering reinforcement due to its high strength,corrosion resistance,and convenient construction.At present,there are more researches on the axial compressive performance of reinforced columns with prestressed steel strands at home and abroad,but less research on the seismic performance of reinforced columns,and mainly for axially compressed columns,and the lack of parameters affecting seismic performance of reinforced columns Analysis and research of restoring force model of eccentric compression reinforced column.On the basis of simulating the seismic test of prestressed steel strands and highperformance mortar-reinforced columns,this paper mainly carried out the following four aspects of work:(1)The ABAQUS finite element analysis software was used to simulate the test of the RC column reinforced with prestressed steel strands and high-performance mortar by this research group.In order to fully consider the bond slip between steel and concrete materials,Cohesive units are set up between the concrete materials to bind the two.Comparing the finite element simulation results with the experimental results,they are in good agreement,which fully proves the rationality of the finite element analysis model.(2)Using the proven ABAQUS finite element model to further study the effects of three parameters of concrete strength,axial compression ratio,and prestress level on the seismic performance of RC columns strengthened with prestressed steel strands and high-performance mortar.The results show that compared with the unreinforced column,the stiffness and ultimate bearing capacity of the reinforced column are greatly improved,and the stiffness degradation and the bearing capacity decrease rate of the reinforced column are slowed down under the same load and displacement.With the increase of concrete strength,axial compression ratio,and prestressing level,the peak load of reinforced columns has increased to varying degrees.When other conditions are the same,the effect of axial compression ratio and concrete strength on the seismic performance of reinforced columns is greater than the prestressed level.(3)On the basis of verifying the rationality of the finite element model,the effects of different eccentricity on the seismic performance of prestressed steel strand-high-performance mortar-reinforced columns under the conditions of low axial compression ratio and high axial compression ratio were analyzed.The results show that whether the axial compression ratio is 0.24 or 0.48 and other parameters remain unchanged,the hysteresis loop area,stiffness,yield load,and ultimate load of the reinforced specimen with a larger eccentricity are smaller than the same axial compression ratio and the eccentricity is small.The reinforced column test piece,and the bearing capacity and stiffness are degraded quickly.The increase of the eccentricity has an adverse effect on the average ultimate bearing capacity and ductility coefficient of the reinforced specimens with a high axial compression ratio,which is greater than that of the reinforced specimens with a low axial compression ratio.(4)Based on the above analysis,the regression curve data of the eccentric column hysteresis calculated by the finite element software was regression fitted.According to the test fitting method,the prestressed steel strands and high-performance mortar reinforced eccentric compression columns were obtained.The restoring force model is in good agreement with the calculated skeleton curve,which can represent the changing trend of the skeleton curve,and can better reflect the hysteretic characteristics of the prestressed steel strand-high performance mortar reinforced eccentric compression column.