When AVM Constructions were tasked with delivering the new Bunnings Warehouse Rockdale site, they engaged InfraBuild Construction Solutions to supply BAMTEC® reinforcing carpet system for the massive 10,000 m2 raft slab.
BAMTEC® was essential in achieving the tight deadline for the new hardware store – especially when they experience unexpected ground conditions. Composed mostly of sand and silt, AVM Constructions had to drive more than 1200 hardwood timber piles, some of them up to 28m deep. The delay related to this additional groundwork required time efficiencies elsewhere to keep to the construction schedule.
BAMTEC® enabled AVM Constructions to place 400 tonnes of reinforcing with just four steelfixers and a mobile crane. This method reduced slab reinforcing from three months using conventional steelfixing to one.
Due to a combination of the difficult ground conditions on site and the high point loadings that the floor would be subjected to when the fit out was completed, the heavily reinforced concrete slab is 270mm thick. The slab was broken into 10 sections to simplify construction, with each section being poured in two halves. Continuous plastic bar chairs were placed to support the first two layers of BAMTEC® carpets, with custom-made steel bar chairs used to support the top two layers of steel.
A special feature of the BAMTEC® carpets, was the inclusion of different diameter bars at different spacings in the same carpets, to more accurately match the design requirements. Where the carpets passed over the driven piers, the centres of the rebars in the carpets reduced from 200-150mm and the weight of the carpets was kept under 1000kg for easy handling.
“Even though BAMTEC® carries a premium to normal rebar, and there was the extra cost of the mobile crane for a month, we still made an overall cost saving of around 10% on the reinforcement, so we couldn’t be happier!”
Vince Mamone, Managing director AVM Constructions
Article published on Thursday, 01 January 2015