Effect of increasing the number of anchors on the flexural performance of FRP-strengthened RC beams

• Published in: Procedia Structural Integrity Vol. 54; pp. 287 - 293
• Main Authors: Hawileh, Rami A., Assad, Maha, Abdalla, Jamal A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2024
• Subjects: Carbon fiber reinforced polymers (CFRP); Fibre Reinforced Polymers (FRP); FRP anchors; Fibre Reinforced Polymers (FRP); Carbon fiber reinforced polymers (CFRP); FRP anchors
• ISSN: 2452-3216; 2452-3216
• DOI: 10.1016/j.prostr.2024.01.085

Fiber-reinforced polymers (FRP) have been extensively used in external strengthening and retrofitting of existing reinforced concrete (RC) structures. Beams strengthened with FRP sheets exhibit improved performance in terms of flexural capacity. However, the ductility of the beams is sacrificed due to the brittle failure of externally bonded FRP sheets in the form of FRP debonding or concrete cover delamination. Spike anchorage systems were developed to prevent or mitigate debonding of FRP sheets in externally strengthened RC beams. This study aims to investigate the effect of increasing the number of FRP spike anchors at the laminate's ends on the flexural behavior of strengthened and anchored RC beams. Three concrete beams having a length, depth, and width of 2000, 250, 200 mm, respectively, were tested under a four-point bending test. The first beam was strengthened and unanchored, and the other two beams were strengthened and anchored with one or two 14-mm diameter FRP anchors on each side, respectively. Results showed that increasing the number of anchors significantly improved the flexural behavior of the strengthened beam in terms of the beam's response at failure and the strain utilized in the FRP laminates. The strain utilization percentages as reported in the tested beams were 27%, 61%, and 99%, for the control unanchored, anchored with two anchors, and anchored with four anchors, respectively. Thus, it can be concluded that anchoring FRP sheets with two anchors at the laminate's ends if feasible is more effective than one anchor in delaying debonding failure, and thus would lead to a better enhancement in the flexural performance of strengthened RC beams.