Flexural strengthening of reinforced concrete slab–column connection using CFRP sheets

• 6 specimens were tested, 3 control specimens and 3 CFRP strengthened counterparts.
• The proposed strengthening scheme was proven to be effective and have sufficient anchorage.
• Effect of column eccentricity on concentric, eccentric and edge columns was studied.
• Alteration in ductility due to the application of CFRP sheets and column eccentricity was studied.
• Code-based predicted capacities were not conservative for CFRP-reinforced eccentric columns.

The objective of this paper is to investigate experimentally the effectiveness of application of carbon fiber reinforced polymer (CFRP) sheets as a strengthening technique of a reinforced concrete (RC) slab–column connection in one-way flat-plate system to enhance its flexural strength. The experimental study was particularly conducted to examine whether there is enough anchorage with the use of CFRP wrapping to the discontinuous longitudinal CFRP sheets at column stub. Series of tests were conducted on six flat slab–column connection specimens organized in two groups of three specimens each. The first group included three control specimens with central, eccentric, and edge columns, respectively. The second group was geometrically identical to the first group, though with CFRP sheets installed on the tension side of the slab to increase flexural capacity at the negative moment region. The specimens with eccentric and edge columns are those having geometrical eccentricity and whose results are compared with those obtained for specimens with central column to study the effect of column eccentricity. The experimental work included fabrication of specimens and testing them under increasing monotonic gravity loads up to failure. Experimental results demonstrated that the flexural ultimate load carrying capacity increased by 33%, 37% and 67% for the tested specimens with central, eccentric, and edge column, respectively, when strengthened using CFRP sheets. The cross-sectional analysis was also undertaken to compare the experimental results with those obtained from Canadian Standards for FRP design for buildings.