Challenging the Status Quo - An innovative approach to the structural rehabilitation of an existing box culvert

Abstract

Inspection and Level 3 Structural Assessment of a large twin-cell reinforced concrete box culvert beneath the Brisbane Corso found the southern cell was deteriorating and rapidly reaching the end of its structural lifespan. The deteriorated culvert runs beneath a high-volume traffic area on a bus route, also used extensively by large groups of cyclists and families. Its outlet is in a small, environmentally sensitive section of parkland alongside the Brisbane River. Long term closure of the Corso, while a new reinforced concrete culvert was constructed, would have been unacceptable. Consequently, rehabilitation with a structural lining within six months was considered a potentially feasible alternative. The liner would need to be structurally designed to take all load independent of the existing culvert. Its location close to the Brisbane River meant that the liner installation process would have to manage tidal effects as well as the passage of normal stormwater flows. With these constraints in mind, Council requested innovative design and construction options to minimise community and environmental impact while also reducing the time frame compared with RC solutions. Interflow worked with Council to consider options available both nationally and internationally to meet the technical design aspects of the project as well as the community and environmental aspects. After much consideration, Council accepted Interflow’s offer of Channeline, a bespoke manufactured GRP box-section solution, that was able to meet all the project requirements. This paper will provide details on the design process, the Channeline technology, installation, safety practices, environmental controls and how this choice met the substantial challenges faced while working beneath the Brisbane Corso.