Bridges

The Bruce Highway Upgrade project is a $932m highway improvement scheme between Caloundra Road and Sunshine Motorway (CR2SM) on the Sunshine Coast in Queensland. The project involves the widening of the existing highway to 6 lanes over a heavily trafficked 9km length highway. The project incorporates two major interchange upgrades as well as multiple creek and river crossings. The purpose of the upgrade was to provide a safe, high-volume and flood immune section of highway between Caloundra and Sippy Downs. The northern interchange at the Sunshine Motorway removed signalised intersections to provide free-flowing grade separation between the two motorways.

The southern interchange at Caloundra Road incorporates Australiaís first Diverging Diamond Interchange (DDI) utilising two new bridge structures to carry Caloundra Road over the Bruce Highway. The DDI replaced the existing interchange and reduced the project footprint adjacent to the Beerwah State Forest without the need for significant additional land-take. The project included the integration of a local service road parallel to the Bruce Highway which acts as an alternate route for local traffic and short-distance commuters.

Twenty new bridges comprising of prestressed concrete girders and deck-units were employed along with three new box-culvert type structures for active-transport links. Twelve structures cross rivers and creeks where peak flow velocities of up to 6m/s can occur during major flood events. All bridges were founded on cast in-place piles which were socketed into the underlying rock. This paper discusses some of the bridge solutions adopted to provide resilient and durable structures. Discussion on the merits and benefits that DDI interchange design offered the project is also provided. The paper also reviews some of the technical challenges associated with the construction of the upgrade while maintaining live traffic operations as well as addressing some of the techniques undertaken to ensure efficiency during construction.