Strengthening of Concrete Bridge Girders with Concavely-Curved Soffit Using Fiber Reinforced Polymer

Recently composite materials have been increasingly used in different structural engineering applications. The research reported here focuses on the performance of concavely curved soffit reinforced concrete beams strengthened by carbon fiber reinforced polymer (CFRP). CFRP composites used to strengthen reinforced concrete members with curved soffits generally try to straighten under load, resulting in normal tensile stress at the interface between the adhesive and the concrete. Therefore, these structural members may experience premature CFRP de-bonding due to the high concentration of tensile stresses generated by the induced curvature. Interfacial cracking followed by de-bonding is the dominant failure mode. The objective of this research is to study experimentally the effect of soffit curvature on de-bonding failure mode, deformability and load capacity of reinforced concrete beams strengthened with CFRP. A testing program including eight simply-supported beams 2.7 m length was conducted to determine the influence of concavity on the performance and capacity of these types of structural members. CFRP laminates and sheets were used for external strengthening, and all specimens were tested under three-point monotonic static loading up to failure.