35 Wellington Street, East Perth WA
Vibe on Wellington
Campion Design Group
No. of Panels:
533 (Austral Deck) 736 (Wall Panels) 75 (Upstands) 28 (Staircases)
Gary Peters, Douglas Mark Black, and courtesy University of Western Australia
The speed and convenience of precast with the structural integrity of a slab. That’s the claim for Austral Deck. But does it stack up?
Lighter. Faster. Safer. Flexible. Economical.
Those are the five key advantages offered by Austral Precast’s Austral Deck flooring system. So what is the Austral Deck system and how does it work?
Conventional suspended concrete floor slabs are cast in situ on a formwork base, sometimes timber or often a metal ‘tray’, which is supported at frequent intervals by a forest of props. The formwork is then fitted with reinforcement mesh, and concrete poured and screeded to the finished height.
It sounds simple and basic … and it is. It’s also very slow, and time is money, no more so than on a large commercial or multi-residential project.
The Austral Deck system however combines the speed of precast elements with the considerable structural qualities of a monolithic floor slab.
Here’s how it works. The Austral Deck elements, let’s call them concrete planks, are precast in lengths up to 12 metres and a standard width of 2.5 metres. Thicknesses vary from 60mm to 75mm and 90mm, to suit the required loading specification. Like all precast concrete products, each unit is custom made, with dimensions to specification.
The plank is reinforced and also has multiple rows of triangular truss reinforcement (steel lattice girders) following the length of the plank. These are embedded into the precast plank and significantly increase both the strength and the unpropped span of the Austral Deck.
Cast-in items such as ferrules, conduits, and other service fittings and penetrations can be incorporated during manufacture. The system also allows for void formers to be placed and secured on top of the planks to reduce the concrete required for the in situ pour, typically by 30 percent.
After curing, the Austral Deck planks are then transported to site and craned into position, instantly creating a strong, safe working surface that will easily carry the load of trades and their materials. This means work on routing floor services can begin immediately.
A layer of reinforcing mesh is then positioned and tied, and a layer of concrete poured and screeded to the finished height. The result is a strong, composite floor slab with the structural benefits of a conventional monolithic slab.
To get a better idea of the product from a users perspective we spoke to a leading Perth builder, Rodney Naef, about the use of Austral Deck on an eight-storey apartment building as it approached the end of its structural phase. The project, Vibe Apartments, is located in Wellington Street, East Perth close to the restaurant and cafe life of this newlyregenerated inner suburb.
Once completed in early 2015, Vibe will have sixty apartments, mostly one- and two-bedroom, including five two-storey penthouses, as well a gym, pool, two levels of parking (one below grade), and even a rooftop garden, outdoor theatre and viewing deck.
Rodney Naef of Ren Construction is an old hand when it comes to building in precast, both walling and flooring, and his enthusiasm for the Austral Deck system is undimmed.
“It’s quick,” he says, “very quick.” Rod describes the preparation required for a conventional in situ monolithic slab as “time-consuming”. “Basically, we’d be up there for three weeks trying to deck it out.”
How does this compare with the Austral Deck? “With the Austral system we ‘d be backpropping for a day, maybe a day-and-a-half, and the next day you’ve got a whole level covered !” According to Austral Precast, an average of ten Austral deck planks covering an area of 150 square metres can be installed per hour.
Rod adds that “You’ve got a nice, clean, safe working deck straight away for everybody to start working on.”
So how quick is quick in the real world? “On this job we have floorplates of about 900 square metres each and we are doing a floor level basically every eleven working days. So it goes in fast.”
Rod was caught by surprise when we asked about any downsides with the Austral Deck system. “Do you know what, I can’t tell you any, to be honest!” He says it’s a little more costly on a material per square metre basis than a conventional in situ slab but this is quickly recouped in time and speed. “So I can’t really give a negative on the system.”
As well as supplying 533 Austral Deck planks, Austral Precast also manufactured 736 precast wall panels for this project, 75 upstands and 28 precast stairs. “The stairs are craned in off the truck, lowered straight in,” to the fire–rated stairwells made from precast panels, of course, “and there’s your access immediately,” he says with enthusiasm.
As we talked to Rod, the final level of the Vibe Apartments project was being poured and the structural phase was all but complete.