Research on seismic behavior of full-scale high-strength concrete frame columns with high axial compression ratios

Based on experimental study on the seismic behavior of 9 full-scale high-strength concrete (HSC) rectangular frame columns with high axial compression ratios, high-strength longitudinal reinforcements and transverse reinforcements and rectangular interlocking ties, their failure mechanism, hysteretic characteristics were discussed. And then the effects of axial compression ratios, concrete strength, arrangement of confinement reinforcement and transverse reinforcement volume ratios on the hysteretic curves, skeleton curves, rigidity, bearing capacity and ductility of specimens were analyzed. The main results are as follows. The cracking lengths of HSC columns are longer than normal-strength concrete (NSC) columns; Observed damage for large-scale column was much severe than that observed for small-scale columns. The hysteretic curves HSC rectangular frame columns with high axial compression ratios and high-strength steels are flatter, and have less dissipation capacity energy, and the descending parts of the hysteretic curves are steeper; The hysteretic curves of the columns whose brittle failures caused by buckling instability of longitudinal reinforcements in the upper non-dense stirrup regions are much flatter and almost have no descending parts.