Post-Fire Performance Enhancement of Pre-loaded RC Short Columns Using CFRP Confinement

Abstract This study presents an experimental investigation on the rehabilitation of fire-damaged reinforced concrete (RC) columns through the removal of the deteriorated concrete cover, its replacement with new normal-strength concrete (NSC), and subsequent full wrapping using carbon fibre-reinforced polymer (CFRP) sheets. The columns were tested under an eccentric load with an eccentricity of e = 90 mm. The experimental program consisted of nine short RC column specimens classified into two groups according to fire exposure temperatures of 500 °C and 700 °C, using a specially designed furnace. In addition, one unexposed control column was tested for comparison. Two fire exposure durations, namely 60 and 120 min, were considered. During fire exposure, the columns were subjected to a pre-applied axial load equal to 50% of the ultimate load capacity of the unexposed control specimen. The experimental results showed that the ultimate load-carrying capacity of the columns decreased with increasing fire temperature and exposure duration. Specifically, columns exposed to 500 °C and 700 °C for 60 and 120 min showed reductions in load-carrying capacity of (11.65%), (14.11%), (20.85%), and (36.8%), respectively, relative to the control column. After rehabilitation using the adopted technique based on NSC replacement and CFRP wrapping, the fire-damaged columns showed improvements in ultimate load-carrying capacity ranging from (32.14%) to (66.02%) relative to the corresponding fire-exposed specimens.