Keller Group, a UK-based geotechnical solutions specialist, has laid the foundation for Australia’s tallest building on Queensland’s Gold Coast.
The building, dubbed Spirit, is being developed by Chinese company Forise. It will be an 89-storey beachfront high-rise with almost 700 luxury apartments. It will also include three levels of retail space and a six-level basement.
At 297m, the AUD1.2bn ($945.24m) residential skyscraper will be among the country’s tallest structures.
Keller was appointed as principal contractor for the foundation work after beating stiff competition.
The scope of works includes site investigation; site clearance and setup; bored piles with precast plunge columns; a 250m diaphragm wall 45m deep to form the basement; and 53 barrettes for the core foundations.
Twenty-six of the barrettes have steel plunge columns weighing up to 43 tonnes, enabling a top-down construction method, which allows the tower to be progressively constructed above ground at the same time as the basement floor slabs are laid.
The 37m long steel plunge columns for around half of the barrettes were sourced from Luxembourg, the only mill that manufactures the size of column needed for this type of project.
The concrete precast columns for the bored piles, weighing 25,000kg each, were installed using in-house designed frames. The project set to complete in March.
Keller project director John Spence said: “Working closely with the client, their consultants and our Diaphragm Wall Global Product Team, we were able to design a scheme that met all the requirements for the extremely high loads imposed by a structure of this size.
“We were also able to redesign the proposed barrettes, reducing their size and complexity and the need for out-of-hours working, all saving the client money.
“We opted for a diaphragm wall for the basement because of the onerous water tightness criteria specified by the client. In order to found it in the argillite rock, we decided to invest in a Bauer cutter from Germany.”