Design Theory and Experimental Study of Strengthening Reinforced Concrete Beams Using Prestressed Carbon Fiber Sheets

To improve the design theory of prestressed carbon fiber sheet reinforcement and enrich its practical application, a corresponding theoretical analysis and experimental study were carried out. According to the ductile failure condition of reinforced concrete (RC) beams and the plane cross-section assumption, the initial tensile strain control range of carbon fiber sheets with different reinforcement layers was analyzed. Based on the requirement of improving the flexural capacity of beams, a calculation method for reinforcement layers and the initial tensile strain of carbon fiber sheets was proposed. According to the requirements of the practice of prestressed carbon fiber sheet reinforcement, a design process for strengthening RC beams with prestressed carbon fiber sheets was proposed. Through the proposed design method and design process, the design and practice of prestressed carbon fiber sheet reinforcement of RC beams were carried out, and a four-point bending test was carried out on a reinforced beam. The results showed that the failure mode of RC beams after reinforcement was plastic failure, which met the designed bearing capacity requirement.