Project Overview

The Westlink M7 is a major connecting road between north and south-west Sydney, with an average of 180,000 motorists daily. Towards Hoxton Park and Prestons, the M7 provides motorists with easy access to the M5 South-West Motorway and key connections across Sydney’s wider southwest. In the north, it provides motorists with easy access to major arterial roads including Great Western Highway and Richmond Rd, as well as the M4.

With a successful track record of working with John Holland Group on previous projects,  Ozcast was selected as the precast concrete supplier to supply solutions at two key motorway segments:

1. Parapets for the widening of the Hoxton Park Bridge, the longest bridge along the M7’s stretch across south-west Sydney and a major infrastructure upgrade as part of the M7-M12 Integration Project.
2. Panels across a network of over 40 traffic and pedestrian bridge structures across the project, including at the Bernera Road exit, at Prestons.

Both were live-road projects, with Ozcast responsible for manufacturing, delivering, and installing hundreds of precast parapets and panels – all within a tightly constrained delivery sequence while keeping traffic moving during construction.

Scope

Carrying the M7 across a 700m stretch over Cowpasture Road, Hoxton Park Bridge was widened by 3.5m to accommodate one additional lane in both directions. Ozcast supplied 872 traffic parapets: 655 installed along the new southbound lane and a further 217 along the new northbound lane. Together, they create a robust safety edge critical to reduce the consequences of a vehicle leaving its intended path.

138 panels were also used for most of the 40 traffic and pedestrian bridge structures, including the Bernera Road exit in Prestons. With each having its own unique geometry and architectural design, and no on-site storage, the project created a range of complex manufacturing, installation, and logistical challenges. Ozcast collaborated closely with all project stakeholders to coordinate the design, production and delivery of each panel.

Two factors were key to the successful installation of the panels. Firstly, each panel had to be custom-designed. From accurate 3D models and consultation with John Holland Group to creating new moulds and matching the shape and geometry to each bridge’s existing architecture (with multiple iterations), this was not a one-size-fits-all approach; it required careful, considered planning.

Secondly, the casting and installation of the panels had to follow a strict construction sequence. Ozcast developed a detailed strategy to guide Leviat – responsible for all lifting and bracing of the panels on the underside of each bridge – and Borger Cranes, the installer, through all project requirements and procedures to overcome unforeseen challenges e.g. requiring alternative machinery and installation methods to suit tricky bridge height clearances.

Just-in-Time (JIT) manufacturing also became a key production strategy due to the lack of on-site storage, working with various lead times from 24 hours (where panels were installed straight off the truck) to one week.