In the heart of the Southbank precinct, on one of Melbourne’s busiest intersections, work has commenced on a revolutionary project. In what will be one of the world’s tallest CLT projects, a 10 storey vertical extension engineered by Vistek is taking place at 55 Southbank. It will more than double the height of the existing structure.
The worlds tallest timber vertical extension, made possible by CLT
When completed, the CLT structure will top out at a height taller than Brock Commons – currently the world’s tallest timber building. The final structure, designed by architects Bates Smart, will be the tallest timber vertical extension in the world. It will demonstrate to building owners and developers a whole new opportunity in creating value from existing property assets.
The original building had been designed so that a vertical extension would be possible. However, if it was executed in steel or concrete it would not have been commercially feasible. The mass of conventional building would have limited the additional floors. With fewer floors, the extension would not yield enough additional square metres to justify the cost. CLT is much lighter than traditional materials such as concrete and steel. This allowed for a total of ten additional habitable floors, adding the required floor space to make the numbers stack up.
CLT’s speedy and low-impact building process also make it ideal for building in such a congested location.
The design process
Vistek are playing a key role in this project by providing the design services for the CLT structure. This involves computer modelling to analyse the complex behaviour of the structure subjected to seismic and wind loading.
Our role also extends deeply into the build methodology. Vistek are currently working closely with the builders Atelier and CLT suppliers KLH (Austria). Working together, the team has addressed the intricate construction sequencing required on such a tight inner-city site. In addition, we have ensured that the design fully exploits the potential schedule and cost savings that the CLT approach to building presents.