Performance And Failure Behavior Of Prestressed Concrete Beams Strengthened With Multi-Layer CFRP: Experimental And Numerical Investigation

This study presents a comprehensive experimental and analytical investigation into the flexural behavior and sustainability implications of reinforced prestressed concrete (PC) beams strengthened externally with Carbon Fiber Reinforced Polymer (CFRP) laminates. The research aimed to evaluate the synergistic effects of varying prestressing force levels (150 kN and 200 kN) and the number of CFRP layers (one, two, and three) on structural performance and long-term durability. Seven full-scale beams were tested under a four-point bending setup. The results demonstrate that CFRP strengthening significantly enhanced the ultimate load-carrying capacity. The experimental work shown increases ranging from 35% to 106.4% compared to the unstrengthened control beam. A corresponding rise in post-cracking flexural stiffness was also observed. However, this substantial gain in strength was accompanied by a significant reduction in ductility, shifting the failure mode from ductile concrete crushing in the control beam to brittle CFRP rupture and interfacial debonding. CFRP strengthening contributes positively to sustainability as it uses less material, reduces the frequency of maintenance, extends the service life of the structure, and decreases carbon emissions compared to conventional retrofitting. Apart from addressing the fundamental trade-off between strength and ductility, the research highlights that further refinements in the application of CFRP will enhance structural efficiency and improve the sustainability of building designs.