Analytical prediction of the linear and nonlinear behaviour of steel beams rehabilitated using FRP sheets

The importance to rehabilitate ageing and deteriorated existing steel structures has motivated researchers to develop simple and efficient rehabilitation techniques. One of the currently developed techniques involves bonding Fibre Reinforced Plastic (FRP) sheets to the flanges of steel beams. This paper presents an analytical model to predict the linear and nonlinear behaviour of steel beams rehabilitated using this technique. The model is based on the solution of the differential equations governing the composite behaviour of a rehabilitated steel beam and includes representation of the peel and shear behaviour of the adhesive material. A bending test was conducted on a W-shaped steel beam, with glass FRP sheets bonded to its flanges, and the experimental results were used to validate the model. The model predictions for the failure load, failure mechanism, midspan deflection, steel strains, and FRP strains were found to be in excellent agreement with the experimental results. The model was also used to predict some parameters that were difficult to evaluate experimentally. This provided a better understanding of the behaviour of the rehabilitated beam.