10. CFRP Strengthened Structure And Monitoring

Carbon Fiber Reinforced Polymer (CFRP) composite fabrics due to their strengths and ease of applications have been employed for repair and strengthening of reinforced concrete bridges. Conventional reinforced concrete elements are designed to fail in a ductile manner. Premature peeling and debonding of CFRP fabrics from the structural elements leads to brittle and abrupt failure of repaired structures.

The objective for this research was to investigate the mechanism of failure and peeling of CFRP fabrics. This was achieved through a detailed experimental program involving measurement of interface debonding of CFRP fabrics from concrete. Moreover a theoretical model was developed for prediction of failure due to peeling of CFRP repaired members. The results from this study are used for proper design of repair schemes for reinforced concrete members.

Fig.1 Reinforced Concrete Beam Subjected to Reverse Four-Point-Bend Loading

Fig.2 Load Versus Center-Point Deflection Response of the Retrofitted Beams

Fig.3 Typical strains in CFRP as measured by the 6-inch gauge optical fiber sensor

Fig.4 Peeling failure of FRP section

Fig.5 Placement of 8-sensing section of DFOS for beam fatigue test

Fig.6 Sudden shift in interface strain due to debonding of FRP from concrete under fatigue loading