ASEISMIC BEHAVIOR OF HIGH STRENGTH CONCRETE-FILLED RECTANGULAR STEEL TUBULAR COLUMNS WITH HIGH AXIAL LOAD RATIO

To test the aseismic behavior of rectangular steel tubular (HCRST) columns filled with high strength concrete, an experiment of eight specimens was carried out under cyclic lateral load and high axial load ratios varying from 0.5 to 0.7. The hysteretic behavior, deformability, and energy dissipation capacity were measured by the changes of the axial load ratio, steel ratio and the slenderness ratio of the specimens. The influences of the specimen parameter were compared. The experimental results show that there are two failure models of the column including the bucking of the steel tube and the crash of core concrete at the base of the specimens. The HCRST columns have the plump hysteretic curves. There is no significant pinch phenomenon. The ductility coefficient varying from 3.05 to 4.07 and the equivalent viscous damping ratio varying from 0.25 and 0.31 can meet the requirements of aseismic design. The experimental results indicate that HCRST columns with high axial load ratio have excellent earthquake resistace. In addition, a finite element model was established and applied to the analysis by the software of ABAQUS. The numerical simulation results are in agreement well with those of the experiments.