Experimental observation on the seismic performance of reinforced concrete columns with a well-confined plastic hinge...

Seismic performance evaluation was conducted on eight circular reinforced concrete columns. Key design parameters for the columns included the number of longitudinal reinforcements, yield strength of reinforcements, vertical spacing of spirals, aspect ratio, and axial force ratio. Test results revealed that all columns exhibited stable as well as ductile response. Using the test results, drift ratios corresponding to various damage states, such as initial yielding, initial cover concrete spalling, initial core concrete crushing, buckling and fracture of longitudinal reinforcement, and the final spalled region were evaluated. The measured drift ratios were then compared with widely accepted drift ratios corresponding to damage limit states. Comparison revealed that the exiting damage limit states were notably conservative. This suggests that drift ratios for damage limit states need to be derived based on experimental observation of reinforced concrete columns designed by a national seismic design practice.