Seismic behavior of steel fiber high-strength concrete columns with HRB600 steel bars

In order to investigate the seismic behavior of high-performance concrete columns with HRB600 steel bars, reversed cyclic load tests on six high-strength concrete columns with square section of 600 mm×600 mm were carried out under high axial compressive forces. The specimens included two normal concrete columns with HRB600 steel bars and four steel fiber concrete columns with HRB600 steel bars. The failure modes, hysteretic properties, bearing capacity, stiffness degradation, ductility and energy dissipation capacity of the test specimens were compared and analyzed. A restoring force model for steel fiber high-strength concrete column with HRB600 steel bars was established based on the test results. The results show that steel fibers can reduce the crack width of the high-strength concrete columns, prevent the concrete cover from peeling off, decrease the residual deformation of the columns and improve their restorability after earthquakes. The steel fiber high-strength concrete columns with HRB600 steel bars have good deformation capacity, and furthermore, the displacement ductility coefficient increases with the increase of the steel fiber content. The restoring force model of the steel fiber reinforced concrete columns with HRB600 steel bars based on experimental data is calculated accurately, and this kind of columns have good seismic performance and can satisfy the requirements of the seismic design code, making them suitable for engineering application. © 2019, Editorial Office of Journal of Building Structures. All right reserved.