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How top-down construction is speeding up work on Sydney’s tallest tower

Construction projects can be prone to delays. In commercial construction there is a tendency to assume that major deadlines might have to be pushed back.

So it makes sense to look at how we can speed up the entire building process, without impacting on safety.

Under construction right now, Crown Sydney will be the city’s tallest tower when it’s finished in 2021. Located in the former docks next to the central business district, an area known as Barangaroo, the structure is being built as part of a regeneration project, and will house a hotel and casino.

The tower is part of a $4.4 billion scheme made up of offices, shops, hotels, apartments and restaurants. In many ways it sounds much like any other mixed-use development. What is different about it is that the construction method used for the tower is an innovative one.

Unusually, this 271-metre (890-feet) tower is being built using top-down construction. It is a unique methodology, which will see construction happening in both directions from the established concrete slab on the ground floor.

In fact, the term “top-down” is a little misleading here, as what they are actually doing is building in two directions at once. Workers will simultaneously build upwards while the three basement levels are being excavated, allowing for a much shorter construction time-frame.

Advanced ventilation systems will allow teams to work in the basement, and they have developed a modified shipping container system to offload contaminated fill from the basement.

This highly efficient system sees a truck bringing an empty shipping container to the site, which is lifted off the truck using a gantry crane. A fully loaded shipping container is then immediately lifted onto the truck and taken away for safe disposal, in order to minimise journeys to and from the site.

With the site having been an industrial plant in its previous life, covering the footprint of the building before beginning excavation has made working at the site more straightforward.

Basement construction workers still need protective clothing, and an advanced ventilation system ensures their safety, but the contaminated soil is not exposed to the elements.

It’s a fascinating example of modern construction methodology being applied both to simplify and speed up a project, and I will be following it with interest.

Remember, if you need assistance with the structural element of an upcoming project, you can get in touch with me, or one of my team.

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