ECONOMIC VIABILITY OF STRUCTURES WITH FRP REINFORCEMENT AND PRESTRESS

Most of the technical problems associated with the use of FRPs have been addressed; they offer a good technical solution to the problems of corrosion of reinforcement. However, apart from the use of glued-on CFRP strips for flexure, FRPs are not finding their way into mainstream use. The reason is economic, since the first cost of the materials is higher than steel and the discount rates used to produce NPV mean that future repair costs have negligible effect now. Industry's perception is that FRPs are uneconomic for newly-built structures, so they are not used. In this paper the true cost of steel corrosion is addressed, using realistic models for chloride and water ingress, traffic delay costs and realistic repair costs; an appropriate discount rate is also discussed. These models are applied to the survey of 257,000 bridges in the US and predictions are made for the money that could be saved if future bridges were built using non-corroding FRPs. Unlike present calculations which (conveniently for the politicians) show that cheapest first cost is also the cheapest whole-life cost, the results show that additional money spent now on improving the durability of structures is a very sound investment.