Construction of the $2 billion Sydney Westfield flagship project in the city’s Pitt Street Mall has made history with its 72 hour erection time frame. In this industry, time is money and development delivery can make or break a project.
Taking place over two weekends in the dead of night so as not to disrupt one of the city’s most expensive and busiest retail strips, the shell of this four-storey building was erected in just three days, with a goal of being fully completed by Christmas.
How is it that a world-class development could be erected in just three days, when even the project manager of Cerno Management, Paul di Cristo attests conventional methods of construction on a project of this caliber generally takes three to four months?
Through the use of precast materials.
Specialist precast builders Baseline Constructions worked succinctly with project management and the precast manufacturer, both members of the National Precast Concrete Association, in order to deliver a 100 per cent precast structure. In delivering in this manner, the time frame surrounding the erection process was cut by months, ensuring maximum efficiency in regards to both timing and budget.
The structure itself has a gross floor area of 180 square metres, with floor-to-floor heights of 4.5 metres. In order to make the most of the floorspace, architects the Buchan Group excluded interior columns, meaning key walls would be load-bearing. Frameless glass windows have also been included for maximum transparency and stock exposure.
The entire structure encompasses 69 wall panels at thicknesses of 180 mm, 200 mm and 220mm. Welded steel connections cast into the concrete precast structural units provide the building with stability under lateral loading.
While precast offers a speedy and efficient delivery process, there is a major challenge associated with this type of delivery that is often forgotten – working with ready-made elements leaves zero room for error.
“We manufactured the wall and floor components to the tightest specifications after extensive consultation with the architect and builder,” says Chris Parsons, of Hanson Precast. “This significantly reduced labour, materials and other costs and wastage associated with a conventional build of this style. There was no room for error on the project, and no second chances.”
This precision extended to the planning controls, strict time frame and the crane-hoisting of elements, the last of which also posed a serious challenge. The tight location of the development meant that vehicular access was an impossibility and the craning process had to be almost surgically assessed and addressed in order to correctly assemble the structural elements.
In undertaking all of the above processes with a critical focus on precision and communication, the team was successful in delivering a record-breaking development.
“This project represents the future of inner-urban construction and is testimony to a whole host of factors – but especially the close teamwork involved,” says Nicholas Bettar, managing director of Baseline Constructions.
Precast delivery is only as efficient as the team that implements it. When undertaken correctly, with the meticulous accuracy necessary, the full potential of this delivery technique can be unlocked, allowing for the completion of world-class developments that are on budget and on time.