| Summary: | Worldwide, a great deal of research is currently being conducted concerning the use of fibre reinforced plastic wraps or laminates in the repair and strengthening of reinforced concrete members. It has been shown that such techniques can be both effective and economical when compared to the existing practice of retrofitting with steel plates. One of the most significant advantages of such systems is the labour cost savings achieved through their ease of application. A novel technique which further simplifies the application procedure is to apply the fibre using a spraying process. By spraying the fibres onto the member surface concurrently with a suitable matrix resin, a two dimensional random distribution of discontinuous fibres is obtained. This work reports the first usage of a sprayed glass fibre reinforced plastic (GFRP) retrofit system on reinforced concrete beams. Using E-glass fibres embedded in a polyester matrix, it was shown that significant increases in load carrying capacity, member stiffness and fracture energy can be achieved with such a system. A comparison of results obtained from small scale specimens with those available from current literature was performed. The sprayed glass FRP procedure produced results similar to those obtained with FRP fabric wraps or plate bonding techniques for flexural strengthening. When used for shear strengthening, the sprayed FRP outperformed all of the other techniques. An analysis technique was developed to predict the ultimate load carrying ability of FRP retrofitted beams as well as their load-deflection behaviour up to failure. In the rehabilitation of large scale bridge channel beams, the sprayed FRP technique was found to be more effective than a commercially available continuous fabric system at upgrading structural properties. An economic comparison revealed that the material costs associated with the sprayed approach can result in a significant savings compared to that same system.
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