Anchoring of the main CFRP sheets with transverse CFRP strips for optimum upgrade of RC Beams: Parametric experimental study

Abstract

This study illuminates the impact of reasonable anchoring of carbon fiber-reinforced polymer (CFRP) composites as an adaptive flexural strengthening technique for reinforced concrete (RC) beams. To assess the usefulness of the proposed anchoring technique, 38 RC beams were fabricated and tested. The specimens were varied in terms of three major parameters including: number of layers of the main CFRP sheets (0, 1, and 2); length of the main CFRP sheets (none, 400, 700, and 1000 mm); and width of the anchoring CFRP strips (none, 50, and 100 mm). The experimental results showed that the proposed anchoring technique significantly enhances the flexural behavior RC beams in terms of its major characteristics. The attained enhancement was governed by the efficiency of the transverse end-anchoring, which allowed the main CFRP sheets to provide higher contribution to the flexural behavior without immature de-bonding due to cracking; even when the nominal capacity was reached. With increased length of the main CFRP sheets, they became more capable of bridging the emerging flexural cracks; which also true when increasing the width of the anchoring CFRP strips. The effects of the studied parameters were evaluated for the ultimate load and deflection, performance factor, energy absorption, displacement, and ductility. The results revealed that with the proposed anchorage system, the contribution of CFRP sheets to the flexural strength can be improved by about 25%, in addition to substantial enhancements in the other performance characteristics.