While it was closed for repairs, citizens of Brisbane, Australia, missed the Brisbane Riverwalk. During the original bridge’s short tenure of seven years, about 3,000 pedestrians and cyclists travelled across the bridge each day. After a flood decimated parts of the Riverwalk in 2011, the Brisbane City Council looked for ways to repair the bridge and make it stronger. The council chose an FRP solution to give the new and improved bridge a better foundation.
The Brisbane Riverwalk, a half-mile bridge along the banks of the Brisbane River, connects a park on one side to wharves on the other. The damaged bridge closed following the flood, and renovations commenced in April 2013. The city shifted priorities for the repair project: Brisbane’s Lord Mayor Graham Quirk told The Brisbane Times in May that construction of the original Riverwalk prioritized sticking to a deadline, while this time the focus was on building a resilient structure.
One step in the renovation project consisted of restoring 18 bridge piles. The piles were renovated last May using QuakeWrap’s PileMedic™ repair system, which uses FRP jackets to repair and strengthen bridge piles. The system impressed the Brisbane council so much so that Mo Ehsani, QuakeWrap’s president, says the city had another repair process in the works, but changed plans after hearing about PileMedic.
Tony White, business development manager at Building Solutions Brisbane, which is the official PileMedic agent of Queensland, says that the city council selected PileMedic for several reasons. First, it provides an impervious barrier preventing moisture and air from entering, which eliminates corrosion. Second, the FRP jackets are an economical solution: Contractors can work in water without divers, the PileMedic jacket can be fitted quickly and the pre-manufactured FRP jackets are cut on-site, reducing waste and manufacturing and shipping costs. The latter is particularly important when considering the expense of shipping materials from the United States to Australia. Ehsani also notes that applying FRP jackets to a concrete pile makes it 50 percent stronger.
So how does the system work? The PileMedic repair system uses biaxial glass or carbon fabric sheets laminated with a vinyl resin layer on each side of the fabric. The pre-manufactured sheets are cut to size for the project on-site, then wrapped around the bridge pile twice and sealed with QuakeWrap’s own epoxy at the end. The jacket is temporarily secured with ratchet straps or shrink wrap while the annular space between the jacket and the pile is filled with grout or resin.