| Hollow Core Produces Economies |
| October 2000 | |
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Success in business increasingly depends on speed of response to new opportunities. CGA Developments recognised the importance of speed in providing new office buildings for two of its important clients MYOB and Motorola, in the rapidly developing Tally Ho business park area of Burwood, 17 km east of Melbourne's CBD. CGA Developments' architect, Millar Watson, and consulting engineer Bonaci Group chose hollow core plank construction for both office buildings, currently being constructed by Hollow Core Concrete P/L for Abigroup Contractor P/L. MYOB's building has five floors and Motorola's three. In the sequential, stepwise construction of the five-floor MYOB facility, the erection of two complete five-level bays of 8*30m, took just 15 days with the entire shell of 1500m2 area per floor, scheduled o be completed in seven weeks. The Motorola shell construction of three floors, each 1440m2, was completed in four weeks. The rapid construction of the jobs is attributable to the combination of prefabricated hollow core planks, beams and columns, supplied by Hollow Core Concrete of Laverton North, Victoria. Hollow core also offers flexibility in the provision of mechanical services, gas and electricity, and new tenant requirement. In office layouts in reduces the number of columns. The Motorola building has planks spanning 11.7 metres, while in the case of MYOB, the span is 8.5 metres. The resultant open space configuration offers flexibility, is adaptable for future tenant requirements and maximises undercover car parking space. The MYOB two-level parking area has an H-Frame construction to provide structural rigidity. With mechanical services, the use of hanging beams, for example, (used in the Motorola building) permits low profile venting. In addition, large sections of hollow core planking can be cut out to accommodate service shafts, and stairwells that may be required with a change of tenancy. The load spreading characteristics of hollow core planks are excellent. For example, a plank, that is part of a 10m span plank floor with screed topping, to which a point load is applied bears only 23% of that load. The two successive planks on either side bear respectively, 21% and 17.5% of the load. The Motorola building uses 300mm thick planks, and the MYOB building, 200m planks. In both instances, the plank floors have an average screed applied of 60 mm on F72 reinforcing mesh. The hollow core system has cost efficiencies by eliminating form work and scaffolding. This in turn, allows access by multiple trades, as well as providing the opportunity to complete the building in a step-wise manner. As an estimate, savings can be 15% of on site concrete pour costs. Overall building costs can be typically improved by 3% or more. |