Marr’s unique challenges to remove Australian TV tower
10 September 2021
A special crane solution was provided by Marr Contracting to dismantle a 233 metre television transmission tower in Australia. Alex Dahm reports
Standing a tower crane more than 200 metres tall with some guy wires and no lateral ties is no mean feat. It was the solution proposed by Australian crane company Marr Contracting as the best way to dismantle a 233 metre disused television transmission tower.
Working with partners, The Men From Marr’s had already removed the top section of the former TCN-9 TX transmission tower at Willoughby, Sydney by the time of writing this in late August 2021.
‘Sydney’s Eiffel Tower’
Back in 1965 Marr helped build ‘Sydney’s Eiffel Tower’, one of three towers known as the Artarmon triangle. They broadcast for major media companies before being decommissioned in February 2021.
Mirvac acquired approval for residential redevelopment and put together a team to dismantle the steel lattice tower. Australian and international engineers and contractors for the job included Marr, Robert Bird Group and Kordia, a critical infrastructure expert.
Challenges were presented by the tower’s size and its location.
“At 233 metres this tower is equal in height to a 77-storey building which posed a number of challenges. So, Mirvac approached us to see if we could come up with a solution, using our tower cranes and bespoke equipment, as an alternative to more traditional methods of deconstruction,” explained Simon Marr, Marr Contracting managing director.
“As the decommissioned tower was not structurally sound enough to attach lateral supports, the challenge from a craneage point of view was to find a way to get the crane hook height above 233 metres without the need to build expensive and complicated temporary structures to support the crane.
“We spent 12 months working with multiple stakeholders, including our lead engineering consultants, Robert Bird Group, to initially assess what was structurally feasible with our existing equipment before designing a unique approach involving the introduction of guy wires to laterally support the tower crane and allow it to climb to the required height to dismantle the tower.
“We helped build the TCN tower back in the 1960s so we were determined to find the best way to bring it down,” Marr added.
More than 200 metres of tower
The first of two tower cranes to be used on the project Is a Favco M310D luffer. It was erected on more than 200 metres of tower and supported by four guy wires anchored to the bedrock via foundations. With 16 tonne winch and 60.5 metre radius boom an M310D will lift 11 tonnes at 20 metres radius and 2.4 tonnes at full radius.
With the smaller and lighter top sections removed the M310D will be climbed down to freestand at 90 metres. At that point the crane will be replaced by a much larger M1280D Favco luffer. This 100 tonner can lift its maximum to a radius of 25 metres and still 13 tonnes at 80 metres. Over the next nine months it will remove the rest of the TV tower in sections weighing up to 60 tonnes.
From his point of view James Hiley, Marr design manager, commented, “From a design perspective, this has been one of the most complex and unique projects that I have ever been involved with. A key ingredient of the success achieved to-date has been the harmonious engagement of multiple stakeholders to produce the best outcome for the client.”
From Mirvac, Clancy Sprouster, senior development manager – residential development, said, “Mirvac has an industry-leading reputation for upholding the highest standards of safety and our design team comprises experts in their field. Partnering with Marr as our craneage experts means we know we are in safe hands.”
Marr said it expects completion by early 2022.