Experimental Study On Seismic Performance Of Three-directional Prestressed Column With High Strength Concrete Filled Core Steel Tube

The arrangement of vertical prestressed reinforcement in the reinforced concrete column,forming vertical prestressed reinforced concrete column can effectively delay the column cracking and reduce its residual deformation. But that will also increase axial compression ratio of the concrete column,and reduce the impact ductility and energy dissipation performance.In view of that, the project team proposed a layout of high strength concrete filled steel tube core column and prestressed steel transverse restraint in concrete column.forming three-directional prestressed column with high strength concrete filled core steel tub.So at the time of delaying cracking, reducing the residual deformation to ensure good ductility and energy dissipation performance in the earthquake.This paper has combined the experimental study and theoretical analysis,and has researched seismic behavior and design method of the three-directional prestressed column with high strength concrete filled core steel tub.That will can provide a useful reference and basis for the research and application of new composite column.In this paper,three shear span ratio of 2.7of the three-way prestressed column with high strength concrete filled core steel tub,and one test specimen for comparison of no prestressing steel lateral restraints have been made of the cyclic loading test.The test mainly inspected the axial compression ratio and vertical prestressed degree effect on seismic performance of the three-directional prestressed composite column.Combined with the crack development and failure modes, and the test result of each specimen of the load deformation hysteretic curves, skeleton curves, stiffness degradation curve, the paper has conducted in-depth research and analysis on seismic behavior of specimens.The results showed:(1)under the circumstances of the same axial force, increasing the degree of prestressing can be increase in the ultimate bearing capacity and the resetting ability of the specimens.But its speed of carrying capacity decay and stiffness degradation will be faster,and the ductility and energy dissipation will be reduced;(2)at the same degree of prestressing, increasing the axial force can increase the ultimate bearing capacity and energy dissipation capacity of the specimens,but its ductility is reduced, while the specimen reset capability factor has little effect.;(3)using prestressed steel strip transverse restraint on the specimen, obviously can improve the ductility and the energy dissipation capacity,and improve the seismic performance of the specimen.According to the analysis of test results, in-depth analysis of shear mechanism and bearing capacity formula of steel reinforced concrete and steel framed reinforced concrete column and concrete filled steel tubular column,using superposition principle,this paper proposed formula for calculating the shear capacity of the three-directional prestressed column with high strength concrete filled core steel tube.It is shown that the formula is reasonable form comparing calculated results with experimental results.