Behavior of Reinforced Concrete Beams Strengthened in Shear Using L-Shaped CFRP Plates: Experimental Investigation
Publication: Journal of Composites for Construction
Volume 18, Issue 2
Abstract
This paper presents the results of an experimental investigation on reinforced concrete (RC) T-beams retrofitted in shear with prefabricated L-shaped carbon fiber–reinforced polymer (CFRP) plates. Shear strengthening of RC beams with L-shaped fiber-reinforced polymer (FRP) plates has proved effective. In this method, grooves are made throughout the beam flange to fully embed the vertical leg of the L-shaped CFRP plate perpendicular to the longitudinal axis of the RC beam and in the RC beam web surface. However, in some cases, drilling grooves in the concrete flange might not be feasible because of the presence of obstacles such as longitudinal steel in the flange of the RC beams. Therefore, the main objective of this investigation was to evaluate the performance of the RC beams strengthened in shear with externally bonded (EB) L-shaped plates as affected by the embedment length of the L-shaped FRP plates. In total, six tests were performed on 2,500-mm long T-beams. Three specimens were strengthened in shear using epoxy-bonded L-shaped CFRP plates with different embedment lengths in the RC beam flange. One specimen was shear-strengthened with fully embedded CFRP plates in the concrete beam flange. The second specimen was strengthened with partial embedment of the L-shaped CFRP plate. This specimen is representative of the case where full penetration of the CFRP plate is not feasible because of an obstacle. In this specimen, the embedment length was set to 25 mm to simulate the minimum concrete cover thickness in RC beams. The third specimen was shear-strengthened with L-shaped CFRP plates with no embedment in the concrete beam flange. In addition, the performance of the beams strengthened with L-shaped CFRP plates was compared with that of a similar specimen strengthened with EB FRP sheets without embedment. Results show that the performance of the specimens strengthened with partially and fully embedded L-shaped CFRP plates in the beam flange was superior to that of the beams strengthened with EB FRP sheets and L-shaped CFRP plates with no embedment.
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Acknowledgments
The authors wish to acknowledge the support provided by the Natural Sciences and Engineering Research Council of Canada through a postdoctoral fellowship to Dr. Mofidi and to Prof. Chaallal through a Discovery grant. The authors thank Sika Canada Inc. (Pointe Claire, QC) for providing the epoxy and the CFRP L-shaped plates. The efficient collaboration of John Lescelleur (senior technician) and Juan Mauricio Rios (technician) is acknowledged.
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Published In
Journal of Composites for Construction
Volume 18 • Issue 2 • April 2014
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Feb 13, 2013
Accepted: May 15, 2013
Published online: May 17, 2013
Discussion open until: Mar 22, 2014
Published in print: Apr 1, 2014
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