SPRAYED FIBER-REINFORCED POLYMERS: FROM LABORATORY TO A REAL BRIDGE

Abstract

A new method of repair for bridges and other structures has been developed that uses sprayed glass fiber reinforced polymer (GFRP) coatings. This technique involves the spray of polymer and short, randomly distributed fibers concurrently on the surface of the concrete to be repaired such that a two-dimensional random distribution of fibers is obtained on the application surface. This article describes the spray process and compares the laboratory performance of GFRP sprayed full-scale bridge girders to those retrofitted with FRP wraps. Results from the laboratory tests show that both retrofit techniques increase member stiffness, but the sprayed GFRP technique produced a 96% increase in ultimate load carrying ability, while the fiber wrap produced only a 33% increase. The sprayed GFRP technique also increased energy absorption to peak load by 195% while the wrap technique increased it by 174%. The specimen with the sprayed GFRP retrofit also showed the greatest ability to strain-harden. The sprayed GFRP technique was applied to a bridge in British Columbia to enhance the shear resistance of its girders, and results of a load test after the bridge was reinforced indicate that the technique was successful.