Development of (FRP) anchorage systems for strengthening box girder bridges in shear and torsion: the case of the West Gate Bridge

Many existing box girder bridges are presently being retrofitted with fibre composite materials in order to achieve greater flexural, shear and torsion strength and to meet the demands of today's escalating traffic loading. The technical challenges involved with such bridge retrofit projects are investigated herein though a case study of the West Gate Bridge project which is one of Melbourne's most iconic and important transportation infrastructure linkages. Innovations in FRP conceptual and detailed design involving FRP anchorage technology, implementation, testing and monitoring have resulted in world class practices in the area of large scale FRP implementation. Efficient FRP anchorage solutions developed specifically for this project, involved the use of unidirectional and bidirectional fabrics together with mechanical substrate strengthening. These solutions have resulted in increased fibre utilization levels, largely attributed to an enhancement of FRP-to-concrete bond strength and a distribution of fibreadhesive stresses over a greater area of concrete.