Behavior of post‐heated rectangular fiber‐reinforced concrete columns strengthened with hybrid welded wire mesh and CFRP strips

This study experimentally investigates the effectiveness of carbon fiber‐reinforced polymer (CFRP) strips combined with near‐surface mounted (NSM) steel bars, as well as a hybrid of CFRP strips and welded wire mesh (WWM) approach for rehabilitating fiber‐reinforced concrete (FRC) rectangular columns damaged by high‐temperature exposure. Eight reinforced concrete RC and FRC columns were subjected to axial compression loads and categorized into four categories, including (i) unheated columns (control samples), (ii) heated columns, (iii) strengthened unheated columns, and (iv) strengthened heated columns. The samples of heated columns were subjected to a temperature of 600°C for 3 h. The columns underwent axial compression testing until reaching failure. The findings of the two proposed strengthening solutions were efficient in restoring the original load‐carrying capacity (by roughly 34.7%–50.7%) and stiffness (by roughly 28.7%–77.6%) of heated unstrengthened FRC columns. The utilization of a hybrid of WWM and CFRP strips was more efficient in significantly restoring the load strength and stiffness of the heated columns.