The numerical and experimental simulation of substandard reinforced concrete columns

Structural members can exhibit varying behaviours during a seismic performance assessment of existing reinforced concrete (RC) structures. However, confinement reinforcement that does not meet code requirements is not fully considered, leading to structural members being generally regarded as brittle. To investigate the performance of substandard RC columns, an experimental and numerical study was conducted to simulate these columns realistically. The research variables were the hook angle, length and spacing of the confinement reinforcement. In total, 14 short RC columns with different confinement details were examined. The findings showed that the performance of the substandard columns was inferior to that of properly confined columns. The numerical simulation results obtained through the finite-element method were extensively compared with experimental outcomes. The simulation results showed reasonable agreement with the experimental results. However, the available stress–strain models proposed for confined concrete did not accurately predict the behaviour of substandard columns. Some recommendations for simulating columns with substandard confinement reinforcement details are discussed.