Evaluation of bond design specifications for concrete girders strengthened with CFRP laminates

Externally bonded carbon fiber reinforced polymer (CFRP) laminates are a feasible and economical alternative to traditional methods for strengthening and stiffening deficient reinforced concrete and prestressed concrete girders. The bond between FRP and concrete is the key factor controlling the behavior of concrete structures that are strengthened with FRP composites. Several experiments show that debonding failure happens frequently before FRP rupture, and therefore the FRP strength cannot be fully utilized. For design accuracy, the FRP strength must be reduced due to the debonding failure. This paper analyzes the effect of the strengthening technique on the response and failure modes of RC beams. A non-linear RC beam element model with bond-slip between the concrete and the FRP laminates is used to study the reduction factor of FRP tensile strength of simply supported strengthened RC beams --Abstract, page iii