Ultimate response of RC beams strengthened with CFRP plates

Poststrengthening and retrofitting is a growing reality, as existing struct ures are required to meet the demands of modem society. Apart from the need to increase load capacity, upgrading of a structure may be necessitated th rough deterioration of the structure by corrosion or accidental damage, a c hange in the structural system, or to rectify initial design and constructi on faults. A commonly observed mode of failure for beams strengthened using carbon-fiber-reinforced polymer composite material plates is one due to th e plate peeling off prematurely and unpredictably at relatively low magnitu des of applied loading. End plate anchorages and long unanchored plate leng ths, which can add significantly to the overall cost of a strengthening sol ution, overcome this problem. This paper presents the results of flexural t ests on ten reinforced concrete beams strengthened with different plate con figurations. A strain compatibility and force equilibrium method of analysi s, coupled with an empirical rule derived from the test data, is demonstrat ed to be effective in predicting the ultimate response of simply supported beams in bending with and without end plate anchorages and irrespective of plate length.