Performance Evaluation and Degradation Study of Anchorage Systems in Prestressed CFRP-Strengthened Concrete Beams under Variable-Amplitude Fatigue

This study systematically investigates the performance and fatigue life assessment of anchorage systems in reinforced concrete (RC) beams strengthened with prestressed carbon fiber reinforced polymer (CFRP) plates under variable-amplitude fatigue loading. By integrating experimental testing and numerical simulation, the mechanical behavior and fatigue performance of RC beams strengthened with two different anchorage systems—rigid self-locking anchorage and wedge-clamp anchorage—were comprehensively analyzed. The experimental results demonstrate that prestressed CFRP plates effectively suppress crack propagation, significantly enhance stiffness, and prolong the fatigue life of RC beams. Among the two systems, the wedge-clamp anchorage exhibited superior anchorage performance, achieving a fatigue life of 1.45 million cycles, which represents a 9.2% improvement compared with the rigid self-locking anchorage system (1.31 million cycles). Furthermore, a fatigue life prediction model based on the stress amplitude of prestressed CFRP reinforcement was established and validated, confirming the reliability of the strengthened beams. The findings not only enrich the theoretical framework of prestressed CFRP plate strengthening technology but also provide technical guidance and practical reference for the strengthening and rehabilitation of deteriorated concrete structures such as aging bridges.