Re-contouring flood plain for housing
PROPERTY developer Nifsan is re-contouring a Gold Coast flood plain into a massive public lake and boardwalk system, sport fields and golf course containing a high density apartment and housing development with water and golf course frontages. Called Emerald Lakes, the 210 ha site, formerly a rural flood plain had to be rezoned with stringent ground work conditions, water containment and public access applying. Hence 50 ha is golf course with watercourses, 37 ha is manmade public lakes and another 37.5 ha public open space and multi-purpose recreation. Building is limited to 31.5 ha or 15 per cent of the area.
Ground works started 10 years ago with an existing hill excavated out and used for pre-loading on the site, before reinstating at a greater height. The golf course was established and the lake system, which includes two residential islands, pumped out and connected to the Nerang River by pipes for tidal flow and full water flushing every 28 days. Acid sulphate soils had to be treated and the low lying site sculpted to hydraulically allow flood water dispersion in a man made waterways environment while preserving dry land access roads and housing precincts. All civil engineering design and construction works were done in-house.
Nifsan Constructions, the development’s building arm, is currently constructing Stage 4 The Village – section 4A which comprises three lakeside five-level apartment towers of 76 units, plus commercial area of restaurant, multi-use hall and retail, scheduled for completion in September this year. Construction of the one, two and three bedroom apartment towers is poured concrete floor slabs, stairwell and lift shafts, brick and timber frame exterior walls with internal CSR shaft wall system with CSR fire check sheets. Deep 1.8m x 6m wide balconies are a feature and glazing is a mix of sliding doors and stacker doors.
A basement car park 120m x 30m wide with a footprint of 5,000m2 is only 0.5m above the water table with some footings below water level so some dewatering occurred. Footings are a combination of pad footings, strip footings, driven piles and bored piers. Piles had to be driven around stormwater pipes and the podium slab, which acts as a transfer slab is suspended on perimeter strip footings and columns. Internal pad footings were placed for the columns. The podium slab is 1.7m thick in places and varies between 350 mm to 1.7m because of differing site levels. This meant horizontal concrete control joints were put in the slabs in buildings 1, 2 and 3 and split pours were used for the 4,500m2 podium slab. All slabs in the towers are suspended slabs bearing on internal and perimeter columns.
The Meva formwork system is being used for the concrete slab construction. This aluminium modular horizontal formwork system uses pans which sit on top of the frame and are designed to be manhandled and moved by hoist or crane from floor to floor. The formwork contractor is Pryme. The building works are scaffolded to the perimeter for five floors, decked out every 2m and fully surrounded with shade cloth and safety mesh. All concrete is being placed by a concrete boom pump with a reach of 36m to 52m.
Nifsan Constructions has placed a Comansa tower crane with a 70m jib, 42m tower supplied by Lindores on one side of the 6,000m2 footprint construction site and a Leibherr 71 EC tower crane with a 45m jib, 34m tower on the other. While cranage is sufficient to cover the site and building needs, Nifsan made all contractors responsible for their own materials handling for all horizontal movement and deliveries. Subcontractors came on site with their own small Manitou , Hiabs and telehandlers. Currently servicing all formwork is a 4WD Manitou 3.5t with 12m reach which takes formwork from the large lay down area to the cranage area and can reach out 8m and up to the third building level. A 20t Kato telescopic mobile crane with 31m boom is currently servicing loading bays to building 1.
The landscaping is irrigated from the lake. All towers face east/north east overlooking a vast expanse of lake to the distant cityscape and ocean. But there is a highly decorative surprise element to these units, not yet seen on the Gold Coast. The facades will be painted, trompe l’oeil style in vibrant colours to replicate Italy’s famous Portafino hillside town on the Amalfi Coast.
Source: Construction Contractor