RELIABILITY OF RC MEMBERS STRENGTHENED WITH CFRP LAMINATES

Strengthening of concrete structures in flexure with externally epoxy- bonded carbon-fiber-reinforced plastic (CFRP) laminates is becoming an increasingly popular retrofit technique among researchers and enginee rs worldwide. A reliability study of such structures is the topic of t his paper. First, considering the statistical character of the design variables (geometry, material properties), the effect of changes in th ese variables on the flexural capacity of CFRP-strengthened members is established. Variabilities in concrete strength and CFRP failure stra in and area fraction are most influencial on flexural strength. Next, strength reduction factors are derived, with the aim of achieving a un iform reliability index of about three over a broad spectrum of design conditions. A general strength reduction factor phi = 0.80 is propose d. Finally, the effect of each design variable on the reliability of t he system is examined and quantified in terms of the reliability index .