Abstract
Over the past few decades, utilizing fiber-reinforced polymer in strengthening or rehabilitation of structural members has become a highly promising technique to extend reinforced concrete (RC) structures' lifespan and enhance their structural integrity. Rehabilitation of old structures is necessary due to various factors, including harsh environments, earthquakes, increased loads, corrosion in reinforcement, and inadequate design. Numerous studies have examined the strengthening of RC beams in shear and flexure using carbon fiber reinforced polymer (CFRP) composites with different schemes, including bonding CFRP externally, through experimental and theoretical investigations. In this study, a series of eight RC beams was cast with low-strength concrete. The beams were designed to be weak in flexural. Flexural critical RC beams were strengthened with different CFRP application schemes. The experimental findings were validated through both numerical and analytical analyses, demonstrating close agreement. The results indicate that the application of CFRP laminate or fabric increased the ultimate load in flexural strengthening applications by approximately 40–60%, particularly when CFRP was bonded to the bottom soffit with CFRP U-jacketing placed at both ends. Furthermore, placing a 50 cm CFRP U-jacket at both ends of RC beams, critical in flexural and strengthened using a CFRP laminate at the soffit of the section, led to a 120% increase in load capacity with elastic behavior.