Architect and Builder Magazine South Africa Dec 2017 / Jan 2018 - Page 25

This Northern block is expressed in a grid of steel structure and finished in a corrugated cladding. This and the south-light saw-tooth roof structure refer to the historical grain-delivery track shed at the Silo itself. The roof provides an even spread of light over the primary training area and pool, deep into the building. In additional to the entrances to the apartments and the gym, the ground levels of both buildings include retail units that provide amenity and emphasise the urban, public nature of the public realm. A restaurant spills out from below the gym and a florist and audio shop below the apartments. assistance of cantilevering concrete walls and an intricate supporting structural steelwork system to deal with the corner cantilevers. The external fire escape stairs, gym walkway bridge, feature liftshaft and pop-out structures are predominantly lightweight steel structures that are transferred at podium level. Post-tensioning was tricky on this project due to select off-shutter slab edges, exposed concrete soffits, cast-in slab edge steelwork and other limitations on positioning of live ends and stress boxes due to congested cast-in services, fa├žade mullion fixing positions and balustrades. Structural and Civil Engineering Engineered by Sutherland, Silos 3 & 4 structure are made up of 3 individual towers consisting of 8, 10 and 12 suspended levels constructed above a retail podium level and 2 levels of basement parking. The basement is encompassed by a 400mm wide reinforced concrete sheetpile lateral support wall with a significant drainage system to cope with the water ingress as the structure is approximately 13m away from the sea wall with the lowest basement level situated 2m below mean sea level. Concrete mix designs, steelwork galvanising and paint specifications on this project were driven by exposure to severe marine conditions and were impacted by the Greenstar requirements. The make-up of the gym and residential structure is typically 280mm flat soffit unbonded post-tensioned slabs spanning internal structural grids of 7.5x8.5m, flat soffit balcony slabs varying in thickness between 220mm and 180mm spanning the 8.5m structural grid and cantilevering 3.8m over the Silo public realm below with the No 3 & 4 Silos 25