Mechanical anchorage and predictive modeling of flexural performance for <scp>RC</scp> beams strengthened with <scp>GFRP</scp> ‐ <scp>ECC</scp> hybrid systems

Abstract The focus of this paper is to systematically investigate the flexural performance of reinforced concrete (RC) beams hybrid‐strengthened with glass fiber‐reinforced polymer and engineering cement‐based composites (ECC), and to evaluate the reinforcement efficiency and ductility performance of retrofitted beams using surface preparation and anchoring methods. One control beam and 11 strengthened beams with varying ECC layer thicknesses, anchoring techniques, and surface treatments were tested. Two failure modes—debonding and fracture—were observed. Results indicated that U‐shaped continuous anchoring achieved optimal load‐bearing capacity (14.38% increase) and reinforcement efficiency (76%) compared to the control beam. Analysis of four ductility indicators revealed that U‐shaped interval anchoring with paste application exhibited the highest ductility index (2.29) and comprehensive performance index (2.38). Finally, a cross‐sectional analysis method was employed to calculate the bearing capacity of hybrid‐strengthened RC beams, and a prediction model for flexural behavior was proposed.