Study On Axial Compression Performance Of Concrete Column Strengthened By Prestressed Steel Hoop

Concrete column reinforced by prestressed steel hoop can provide active restraint on internal columns and reduce the problems of stress lag and low reinforcement efficiency in traditional reinforcement methods,and improve the reinforcement effect better.Prestressed steel hoop confined concrete has the characteristics of green,rapid reinforcement and reversible.The prestress of steel hoop can be applied mechanically which is simple.The steel hoop has good mechanical properties and corrosion resistance.These advantages make it have a good prospect of engineering application.The main research work of this paper includes the following three aspects: 1)Axial compression performance tests of 60 prestressed steel hoop reinforced concrete columns,including 42 monotonic loading tests and 18 uniaxial cyclic loading tests.The influence of spacing of steel hoop,column diameter,prestress ratio and initial axial compression ratio on the performance of reinforced columns was studied.2)Based on the test data of 42 monotone axial compression specimens,the calculation models of peak stress,peak strain and the stress-strain relationship of prestressed steel hoop reinforced concrete columns were deduced and compared with the test data.The database of concrete tests with active restraint is established to verify the strength calculation model.3)Using ABAQUS to simulate the axial compression performance of the reinforced column.The axial compression performance of large-size concrete columns under the action of the same hoop ratio and the same hoop spacing is simulated.The test and analysis results show that: 1)The prestressed steel hoop reinforced concrete column under monotonous and cyclic loading can effectively improve the carrying capacity and deformation capacity of the concrete column,and the two curves almost coincide.2)The reinforcement effect will be improved with the increase of hoop ratio of steel.The carrying capacity will increase with the increase of prestressing ratio,but the ductility will decrease.The initial axial compression ratio has no obvious effect on the reinforcement effect.3)The calculation model of actively constrained concrete is in good agreement with the experimental results,and it can be verified by the data in the database.4)The finite element analysis results can well simulate the test results.Under the condition of the same reinforcement ratio and the same hoop spacing,the axial compression carrying capacity of the reinforced column with a diameter of800 mm can be increased by 47% and 17% respectively compared with that of the unreinforced column.The peak strain can also be greatly increased,and the seismic performance can be significantly improved.