Experimental determination of the residual compressive strength of fire-damaged concrete columns retrofitted using CFRP wrapping

The study presented in this paper aimed to experimentally investigate the residual compressive strength of fire-damaged concrete columns retrofitted using carbon fibre-reinforced polymer (CFRP) wrapping sheets. The experimental program involved testing ten column specimens (200 mm × 200 mm × 1500 mm) that were previously exposed to standard fire before being retrofitted using CFRP wrapping sheets. The study imitated a real-life scenario in which concrete columns previously exposed to one- and two-hour standard fire while being subjected to service loads (20% and 40% of the column’s ultimate design capacity) were retrofitted using one and two layers of CFRP wrapping sheets. The test results showed that the effect of increasing the applied load ratio in reducing the post-fire residual compressive strength was more pronounced in the columns wrapped with two layers of CFRP sheets and exposed to a longer fire duration (2 h).