Experimental study on steel reinforced high-strength concrete columns under cyclic lateral force and constant axial load

This paper presents the results of an experimental study on the seismic behavior of steel reinforced high-strength concrete (SRHC) columns. A total of 21 SRHC columns were tested under simulated earthquake loading conditions, and the major experimental parameters were the axial load level, stirrup arrangement, structural steel details and studs. The effects of these parameters on the behavior of the SRHC columns were analyzed in detail. The test results showed that SRHC columns with multiple stirrups and commonly used structural steel ratios demonstrated excellent seismic behavior and were suitable for use in high-rise buildings in seismic regions. The axial load had a negative effect on the energy dissipation and deformation capacity. Stirrups exhibited little effect on the initial stiffness and lateral force at cover spalling, but had a positive effect on the energy dissipation and deformation capacity. The benefit of structural steel was more obvious when the effective confinement index was larger or the SRHC columns were subjected to a greater axial load. Structural steel also improved the positive effect of the stirrups. It is suggested that multiple stirrups should be adopted in SRHC columns to provide full play to structural steel; in addition, more structural steel should be adopted when significant axial loads are applied to SRHC columns. Studs did not significantly affect the performance of SRHC columns during the early loading stage. However, columns with studs exhibited better energy dissipation and deformation capacity along with slower stiffness degradation.