Seismic behavior of multi-cell steel reinforced concrete columns: Experimental study

Abstract

In order to investigate the seismic behavior of multi-cell steel reinforced concrete (MSRC) columns, an experimental study of five large-size MSRC columns various in axial load ratio, cross-sectional structures and loading directions was conducted under axial loading and lateral cyclic loading. The failure mode, bearing capacity, ductility, residual deformation, bearing capacity degeneration and energy dissipation capacity were analyzed based on experimental study. The results showed that the damage developments of specimens with multi-cell steel under a large axial load ratio and a small axial load ratio were similar, while the damage developments of specimens with open steel showed significant differences. Meanwhile, the specimens with multi-cell steel exhibited larger bearing capacity, slower bearing capacity degeneration, better energy dissipation capacity and more stable behavior under different axial load ratios compared to specimens with open steel. However, the bearing capacities of specimens with multi-cell steel showed a sudden decline after the peak point and the ductility index was smaller than that of specimens with open steel. While when the confinement effects on concrete in different regions of cross-section were reasonably designed, the post peak behavior of specimens with multi-cell steel will be significantly improved. Based on the experimental results, a fiber-based method considering concrete in different regions experiencing different confinement effects was proposed to predict the backbone curves of five specimens. The predicted curves showed good agreement with the test curves. The errors of the peak bearing capacity and peak displacement ranged from −8.3% to 5% and −10% to −14%.