03 December 2018
Mainline Demolition and Georgiou Group
Old Mandurah Traffic Bridge Replacement
Erith Contractors (United Kingdom)
Priestly Demolition (Canada)
“The project showed fabulous innovation in both equipment and technique”
With the Civils Demolition Award, the south of England monopoly was broken in the most dramatic way possible with Mainline Demolition emerging from a high quality field to take first prize for its work on the Old Mandurah Traffic Bridge in Western Australia.
Of all the 14 categories presented in Dublin, this was the only one to feature the award of a Highly Commended – Erith Contractors almost continuing its run of successes – but Mainline narrowly won out.
The contractor, which continued a tradition of companies from Australia and New Zealand putting forward World Demolition Awards entries, made a point of naming the Georgiou Group, the civil construction company it had worked with on the project, in its entry for 2018.
Using numbers to illustrate the size of a demolition job is not new, but even by this measure the Old Mandurah Bridge – a 23-span structure measuring almost 200 m (660 ft) – was dramatic.
But it was far from the whole story. Mainline’s entry called it “a multiple-challenge opportunity in a live waterway environment. The aged structure, the rapid, variable tidal flows of the estuary, the live traffic and active inner urban shorelines presented many operation challenges.
“The project required constant management of water traffic, the public, and interface with the responsible authorities.”
Mainline described its key innovation as the airbag technology used on the project, with the team using airbags to capture and transport the concrete piers from bridge to shore. The headstock and column group ranged from a four- to a seven-column arrangement, weighing from 14 to 51 t. Mainline’s systems eliminated high-risk lifting of non-specific weights on water and onshore, leading to more efficient transport and disposal and reducing demolition costs by around 40%.