10 - Flexural strengthening application of fibre-reinforced polymer (FRP) plates

Abstract

The use of externally bonded Fiber-Reinforced Polymer (FRP) composite systems for flexural strengthening of structures is the most common application of FRP composites in the civil infrastructure worldwide and has received the greatest amount of research attention. The first uses of externally bonded FRP composite systems for flexural strengthening were on reinforced concrete; however, FRP composites are increasingly being used to strengthen cast iron, modern steel, timber, and masonry in flexure and, in limited cases, wrought iron and riveted steel structures. Most applications of FRP composite systems for flexural strengthening use unstressed FRP plates manufactured in the factory and adhesively bonded to the substrate, mainly due to the relative lack of research and more complicated installation procedure for prestressing technology. This chapter discusses the application of unstressed FRP composite strengthening systems and the current prestressing technology. The chapter focuses on the stages most closely associated with application of FRP strengthening; specification of materials and workmanship, contractor experience, application methods and sequence, site supervision and final inspection, with reference to current guidance and standards. In addition, case studies are used to highlight the practical issues involved in each step.