Seismic Performance Of Concrete Columns Strengthening With Improved Wrapped Steel

China is a country with frequent earthquakes.Earthquake disasters pose a huge threat to personal safety and will also bring huge economic losses to the country.As the main load-bearing specimen in the structure,the column inevitably undergoes cyclical repetitive motion under earthquake action,which leads to plastic deformation.Once the damage will lead to property loss and endanger the life of the personnel,China's seismic code emphasizes that the seismic design of the structure should meet the requirements.Strong column weak beam",its purpose is to improve the structure's resistance to deformation and prevent the structure from collapsing under strong earthquakes.It can be seen that the column plays a role in the seismic design of the structure.Therefore,it is important to study the seismic performance of the column under low-cycle repeated loads.In this paper,a new type of outsourcing angle steel reinforcement method is proposed in combination with the actual application requirements: the binder in the wet cladding method is replaced by the self-compacting concrete with a small thickness,which not only ensures the coordination force of the reinforcement angle steel and the original column concrete.It also plays its own reinforcement.This reinforcement method combines the advantages of the conventional outer angle steel method and the increased section reinforcement method,and at the same time improves the disadvantages of large space occupied by the conventional reinforcement method and insufficient durability of the binder.Based on the study of the axial compression and eccentric compression performance of the composite reinforcement column,the quasi-static test of the reinforcement column is carried out.The seismic performance of the new outsourcing angle steel reinforcement method is systematically analyzed in combination with the test results.The main research contents are as follows: :(1)Considering the parameters of the plate spacing,angle steel type and axial compression ratio,design 10 reinforced concrete columns(one of which is used to test the axial ultimate bearing capacity,and one column is the traditional outer angle steel reinforcement contrast column,the rest)Eight of them are the new type of angled steel reinforcement columns studied in this paper.The low-cycle repeated load test of the column is carried out to observe the failure mode of the specimen,and to extract the seismic performance indexes such as strength,deformation,material strain,hysteresis curve and skeleton curve.(2)Combined with the results of seismic tests,the bearing capacity,ductility,strength and stiffness degradation and energy dissipation capacity of the new type of reinforced columns were analyzed.The results show that compared with the traditional outsourcing angle steel reinforcement column,the new outsourcing angle steel reinforcement column has greatly improved ductility,ultimate bearing capacity,energy consumption capacity and bearing capacity degradation,and the seismic performance has been effectively improved.(3)On the basis of determining the constitutive relation model of the material,the numerical simulation analysis of the seismic performance of the new outsourced angle steel reinforced column is carried out by fiber model method,mainly considering the influence of angle steel model,slab spacing and axial compression ratio parameters,simulation results and The comparison of the measured test results shows that the calculated results agree well with the experimental data.The new outsourcing angle steel reinforcement method has the characteristics of occupying small space,increasing bearing capacity and strong durability.Based on the research of the bearing capacity of the composite reinforcement method,the seismic performance of the composite reinforcement method is further improved,providing theoretical and experimental guidance for practical engineering..