Axial compressive behavior of fire‐damaged RC column strengthened with ECC‐CFRP grid

Abstract To study the axial compressive performance of fire‐damaged reinforced concrete (RC) columns strengthened by engineered cementitious composites (ECC) combined with carbon fiber reinforced polymer (CFRP) grids, eight RC columns were designed and fabricated to analyze the effects of fire exposure time, thickness of the strengthening layer, incorporation of the CFRP grid, and subjecting the strengthening layer to direct compression on the axial compressive performance of the strengthened columns by conducting fire and compressive tests. It was found that the ECC‐CFRP grid strengthening significantly increased the axial compressive load and axial deformation of the columns; the bearing capacity of the strengthened column subjected to fire for a longer period of time was lower under the same strengthening condition; when the thickness of the strengthening layer was increased, the load‐carrying capacity and axial deformation of the column were enhanced; the addition of CFRP grids could further improve the mechanical properties of the repaired column; when the strengthening layer was directly compressed, the axial deformation was significantly reduced, although the bearing capacity would be further increased. An analytical model of the strengthened column was established using the ABAQUS software, and a formula for calculating the bearing capacity of the strengthened column was derived.