Bridges

The Bunbury Outer Ring Road (BORR) is a new 27 km high-standard road connecting Forrest Highway to Bussell Highway, designed to ease congestion and provide a safer, more efficient traffic route for freight, tourists and locals. The BORR alignment primarily passes through greenfield sites and includes eight intersections and numerous structures, including twelve bridges, fauna underpasses, fauna rope structures, feature light poles, retaining walls, noise walls, and screen walls.

Tapered hammerhead piers constructed using reusable fibre-reinforced plastic moulds were adopted on the bridges forming the northern entrance to the BORR, while headstocks constructed using precast shells supported by columns that extend into the ground as piles were adopted for the river bridges. The BORR-Bussell interchange features a curved, highly skewed bridge, with Teeroff beams made continuous through an inline in-situ concrete stitch, integrated with the pier. Thermal control plans were developed for large concrete pours through heat of hydration modelling.

The bridges were designed to minimise whole of life and maintenance costs. Beam supply challenges were overcome through the standardisation of Teeroff beams and setting up a precast yard in Bunbury. Successful project delivery was achieved through collaboration with Alliance design and construction partners, Main Roads WA, and other stakeholders.

This paper provides an overview of the BORR project's key structures and discusses innovative solutions to overcome project constraints and challenges.