FRP materials for the rehabilitation of tubular steel structures, for underwater applications

Tubular structures have become increasingly popular for economic and aesthetic reasons, yet member deterioration and fatigue-cracking of connections is often reported. Therefore, measures for structural upgrading and repair have become imperative. Fibre reinforced polymers (FRPs) have been used widely for the repair of concrete elements, but their application to steel structures has been so far minimal. An encompassing literature review is presented herein relative to the behaviour and use of FRP materials in civil infrastructure, with application to steel. The suitability of such materials to rehabilitate tubular steel members and the structural behaviour of the resulting composite system were investigated experimentally. The programme was tailored primarily to the offshore industry and techniques associated with underwater repair methods. The strengthening process was effective as all composite members exhibited improved structural performance; hence the current research study has proven the feasibility of rehabilitating tubular steel members with advanced composite materials underwater.