Performance recovery of a repaired 4-storey reinforced concrete structure subjected to shake-table testing

Understanding the effects of repair on reinforced concrete (RC) structures is critical to evaluating their performance in future earthquakes. In this research, a system-level approach is taken by repairing a previously damaged 1/4 scale 4-storey RC structure and subjecting it to a series of dynamic excitations via shake table testing. The repair was undertaken using common construction materials with the primary motivation of restoring original performance. The performance of the repaired structure was compared to that of the original structure prior to repairs. It was found that overall initial stiffness of the structure was recovered to 66% of the original initial stiffness and was generally higher in floors where more intensive repair works were undertaken. Damping capacity was quantified via equivalent viscous damping ratio using three different methods. Regardless of the calculation method, the damping capacity recovery was around 80% for low-moderate drifts and 100% for high drifts. While collapse was not induced in the structure, drift ratio demands of over 5% could be achieved both before and after repairs, suggesting a full practical recovery of deformation capacity. Structural strength of the repaired structure was found to be 17% higher than that of the original structure.