The Steel Awards 2015 celebrates world-class steel structures. Here are some of the winners.
“We are going through very tough times in the steel construction industry, yet in spite of this, we are able to produce world-class work – an indication that the future is bright,” said Spencer Erling, awards convenor for the Southern African Institute of Steel Construction (SAISC), during the Steel Awards 2015 function held on 3 September.
This year’s awards saw a new category for cladding being added, which is the brainchild of Dennis White, director of the Southern African Metal Cladding and Roofing Association (SAMCRA), as well as a record number of light steel frame building (LSFB) project entries.
With excellent quality displayed across the board, the Steel Awards 2015 was again a celebration of world-class steel structures.
Winner: Multichoice City
The use of steel, including the mechanised glass louvres, ETFE cushion roof and dramatic cantilever “peak cap” roof, play a vital role in emphasising the filigree steelwork detail of the new flagship building for Multichoice.
Inside, the volumetric atrium features detailed steel staircases and an elegant tubular-strutted arch structure that spans 24m, formed to resist uplift wind forces, which supports air-inflated ETFE cushion cladding.
Structurally, the roof comprises fabricated box girders tapered in section cantilevering generally 12m (maximum being 13,5m). The closed box form is further stabilised by a tubular bracing network.
On the front facade, tubular steel arms cantilever out from the slab behind to support a curvilinear tubular member that supports the active glass louvres and mechanical actuators.
Winner: “Peak cap” at Multichoice City
The underslung cladding to the “peak cap” feature on the new Multichoice City is to a 12m cantilever, which follows its structural shape requirements tapering from width at the support end to an extremely narrow tip.
The project team and judges respectively acknowledged the challenge of hanging unblemished underslung cladding, especially due to the length of the sheet and the hidden fixing type cladding in this instance.
Specialised flashings were incorporated on the edges of the canopy between the roof and the underslung sheets, each with a unique individual radius due to the complex design.
Category: Light steel frame building
Joint winner: House De Clercq and Cottage
Praised for being a perfect example of what LSFB methods are meant for, the judges liked that the light steel frame (LSF) house didn’t try to look like a brick home, but featured exposed LSFB construction that was finished in black paint with some areas left in its original galvanised look.
Other features include hot-rolled steel in H-sections that form the structure of the centre living area, main facade and three patio areas, as well as large glazed openings. To achieve maximum clear views, LSF joists were doubled up and plated with 1,0mm thick galvanised sheet and L-headers.
Joint winner: Mediclinic, Midstream, Centurion
In order to reduce the total load on the supporting structure of this building, Graceland Architects opted for an LSF roof structure, which ended up costing 25% less than timber trusses and 30% less than what welded heavy steel trusses would have cost.
The Ultra-Span® light gauge steel roof truss system, designed by MiTek and fabricated by Hi-Tech Nail Plate, covers 9 100m² of the roof structure and weighs almost 68 tons, just below 7,5kg/m², including purlins, which is extremely light considering some of the roof trusses span 19m with considerable live load and bottom chord loading requirements.
Category: Light steel frame building
Commendation: Kuruman Casino facade
The 300m² Kuruman Casino facade is supported on a light steel framed structure which was factory built. Sheathing comprising oriented strand board (OSB) was fixed to the frame and covered by a vapour-permeable membrane and expanded polystyrene (EPS) insulation boards. The external insulation prevents condensation on the steel frame, adding to the durability of the structure.
According to the project team, the External Thermal Insulation Composite System (ETICS) provided the flexibility to create the intricate features of the architects’ design with attractive durable finishes.
Winner: Zinkwazi Beach House
The judges commended the innovative, yet functional use of steel finished off by skilled and neat fabrication on this project, which is located on steep eastward facing slopes.
To match the functional aspects of the spaces, the enclosed areas are built in concrete and masonry, while the open or transparent spaces, including the glass window walls, are framed by an exposed structural steel structure.
Situated at the coast, special consideration was given to coatings, which is why steel with a high specification duplex paint coating system was used, while the balustrades are fabricated from stainless steel.
Commendation: De Clercq House
Intended to be as open as possible, the large living room, encompassing the kitchen, dining and lounge area, opens to the patio and a wide “stoep”. I-section beams and columns enable the open plan and the cantilever “stoep”, while carrying most of the storey above.
The structure for the first floor is made of cold-formed lipped channels and the walls and roof of light steel frame construction. The roofs are clad with concealed fix sheeting.
The balustrade of the staircase comprises 4,5mm thick, unpainted steel plate, supporting the wooden handrail. The two parts of the house facing the street were covered with 2mm thick, unpainted commercial quality steel. These sheets have now rusted to a dark, reddish-brown colour.
Winner: The Watershed at the V&A Waterfront
A driving force in the redevelopment of a historic warehouse was the need to visually connect the spaces on the various levels, and structural steel proved the ideal material to achieve this.
Alterations involved opening the gable ends of the building and re-routing pedestrians through the warehouse to create an inside-out/outside-in space, with two new floor levels to house an Innovation Hub, exhibition hall and retail tenancies.
The ground floor space has been converted into an undercover street with the upper floors flying over. The existing craft market stalls have been re-constructed as moveable timber units, which is why it was necessary that the 23m wide central area was column-free.
Category: Factory and warehouse
Winner: Value Logistics Distribution Centre
The installation consists of two warehouses of about 13 000m² and 7 000m² respectively, as well as support facilities.
These massive warehouses feature a substantial clear height with columns spaced far apart and the double-pitched Klip-Lok roof supported on light transverse roof trusses, which in turn is carried by long-span longitudinal lattice girders between the columns. In this instance, the lower sections of the columns are made using tilt-up concrete columns.
In addition, the office building is a detailed structure with exposed steel extending to the glass-fronted reception area with ponds and aesthetic decor.
Other winners include the Kirstenbosch Canopy Walkway, “The Boomslang”, which won the Bridge category, and the Medupi Power Station-Air Cooled Condenser, which won the Mining and Industrial category.
Taking top honours, the Tubular category winner, the SKA Africa Radio Antenna Positioner, walked away as the Overall Winner of the Steel Awards 2015.
Full thanks and acknowledgement are given to the Southern African Institute of Steel Construction, who provided the information for this article.