Experimental Study of CFRP Confined Low Strength R.C. Columns under Concentric Loads

The paper presents results of an experimental investigation carried out on reinforced, low strength concrete columns strengthened by Carbon Fiber Reinforced Polymers (CFRP). The columns were tested under concentric compression until failure. The shape and the slenderness of the column, the thickness and the configuration of confinement were the basic parameters considered in the experimental program. The main objective of the investigation was to study the effectiveness of using CFRP as an external strengthening method to increase the ultimate load of the low concrete strength columns. Using the CFRP enhanced the ultimate load of the columns for all specimens, the increase in ultimate load ranges between 15 % and 291 % compared to the control specimens. The partial confinement is not as effective in increasing the column ultimate load as compared with full confinement. The CFRP confinement is not as effective in increasing the ultimate load of square columns as for circular columns. The gain in ultimate load increases as the number of CFRP wraps. The strength behavior was affected by the cross-section shape and slenderness ratio.