Mitchell Freeway Northbound Widening

Dowsing Group delivered specialist concrete slipform safety barrier works as part of the Mitchell Freeway Northbound Widening project.

The project involved construction of multiple concrete safety barrier types while maintaining production efficiency, safety compliance, and asset protection within a live freeway and rail environment.

Works were undertaken along both the verge and median alignments, under constrained access and program conditions.

Scope of works included:

Concrete slipform barriers constructed to precise tolerances to meet performance and compliance requirements, while interfacing with existing pavement and drainage infrastructure.

Works were delivered within a restricted freeway corridor that limited plant movement and concrete supply access. This was mitigated through the construction of truck crossing bays to maintain pour continuity.

Slipform concrete on finished asphalt required refined placement controls to prevent surface damage, while median barrier works were subject to rail closure windows, requiring detailed staging and resource coordination to maintain program.

Earlier shift starts improved production and reduced traffic and temperature impacts. A custom drainage slot installation method eliminated post-installation coring and cutting, delivering time and cost savings. Mould modifications also enabled smooth-profile installation of the 1.27m barrier.

Barrier alignment, embedment and profile tolerances were consistently achieved across all barrier types. Surface protection methods minimised asphalt damage, and proactive logistics and scheduling controls sustained production despite constrained conditions.