The overall winner and the winning projects in each of the different categories of Steel Awards 2011 reflect the outstanding quality of the steel construction industry in all its diversity. Dr Hennie de Clercq, executive director of the Southern African Institute of Steel Construction (SAISC), said at the awards ceremony, “We congratulate the winners and, at the same time, emphasise the exceptional quality of all the entries, which augurs so well for the future of our industry.”
The Steel Awards, hosted by the SAISC, with the Aveng Group as the main sponsor, were staged simultaneously in Johannesburg, Durban and Cape Town on 15th September 2011.
The unique Protea Court rooflight which forms part of the design-changing revamp of Sandton City was announced the overall winner in Steel Awards 2011.
According to the judges, the unusual excellence of the Protea Court rooflight left them in no doubt as to its worthiness of top honours in the awards programme. “In terms of excellence in the use of steelwork architecturally, structurally and technically, there is no doubt that this project can proudly take its place among the many brilliant winners of past Steel Awards,” the judges said.
In a first for South Africa, the Protea Court rooflight joins a number of international projects – such as the water cube in Beijing and the Eden project in Cornwall – in using EFTE plastic bag-like roof cladding, which is kept inflated with compressed air.
Regarding the structure, the judges noted that in plan it looks quite simple. How difficult could it be to construct the spokes of two wheels, each of different diameter, one within the other, but having different origins? However, add a third – vertical – dimension, angle the base of the outer support circle, and curve each of the spokes in elevation, and the structure becomes a significant challenge.
The outer circle is 44m in diameter, in plan, and the whole structure slopes at 11°, which results in eaves’ heights that vary by more than 8.5m. The roof beams are at 30° to each other, are made up of tapering plate girders and are supported internally on a reinforced concrete tower and externally on a latticed box girder. The boxed girder is supported on 12 bifurcated column heads.
The judges noted further that even the secondary tubular members between the rafters are curved, “making every single piece of steel its own masterpiece”.
The judges cited the superb cooperation among the steelwork teams, the meticulous detailing, the accuracy of manufacture and trial assembly in the yard before dispatch to site, plus the accuracy of erection, all as factors which ensured that this most challenging plan came together successfully.
Protea Court Rooflight, Sandton City
Project Team
Developer/Owner: Liberty Properties
Architect: MDS Architecture in association with MMA Architects
Structural Engineer: AKI (now part of Aurecon Group)
Quantity Surveyor: MLC in association with Crane QS
Project Manager: GHC Bryden Project Management
Main Contractor: Sandton City Joint Venture: GLTA & WBHO
Steelwork Contractors: Tass Engineering, Cadcon
Detailer: 3D Struct
Erector: Onpar Steel Erection Works
The Moses Mabhida Station was the winning project in the Architecture Category. Although it may be dwarfed in size by its iconic neighbour, the Moses Mabhida soccer stadium, the station more than holds its own in design excellence and the judges saw it as a worthy winner in the architecture category.
They said, “The design sets a new standard in transport architecture and brings dignity to South Africa’s neglected public transport network. It has been many years since we’ve seen an inspiring train station in South Africa, but this one is certainly inspirational.”
The use of self-weathering Cor-Ten steel defines the striking character of the building and resonates with Durban’s marine and industrial context.
It was noted that “by day, sunlight enlivens the juxtaposition of the materials and steel structure, creating diffused woven shadows along the concourse. At night the station transforms into a glowing woven lantern.”
Moses Mabhida Station, Durban
Project Team
Developer/Owner: PRASA
Architect: Arup
Structural Engineer: Iliso Consulting
Quantity Surveyor: LDM Consulting
Project Manager: Arcus Gibb
Main Contractor: Grinaker-LTA Building East
Steelwork Contractors: Impact Engineering Durban
Detailer: Precise Structural Modelling
Cor-Ten steel cladding and roofing, balustrades, handrails, gate:
MJ Cheater, Rebcon Engineering
The Royal Bafokeng’s Lebone II College in the North West Province won a commendation in the Architecture category. Inspired by Bafokeng King, Kgosi Leruo Molotlegi, Lebone II College is a new school campus with classrooms, administration-cum-civic buildings and accommodation for staff and students.
According to the developers, the design of the college represents a microcosm of a village-city plan and includes a range of structures, from civic-scale to the smaller living units for staff and students.
The judges commended the excellent steel structural forms and the extensive use of exposed steelwork. They noted particularly, “The tensile canopy structure, which takes centre court, is designed without welded connections, transmuting traditional weaving crafts with steel technology.”
One of the unique features of the steelwork was inspired by a recurring African production theme of assembling an element from smaller pieces that one person can carry, with the whole being assembled solely by manpower. The art of weaving, so integral to traditional African culture, was also an important influence on this structure.
“Apart from their obvious aesthetic success, these ‘traditional’ principles employed by the design team also enabled an efficient, sustainable and environment-friendly use of materials,” the judges said.
Lebone College II, North West
Project Team
Developer/Owner: Royal Bafokeng Administration
Architect: Activate Architecture & Afritects Architects – in association
Structural Engineer: WSP & Asakheni – in association
Quantity Surveyor: De Leeuw Group & MMQS – in association
Project Manager: Bigen Africa + Pro Arnan - in association
Main Contractor: JST Construction & Stefanutti Stocks
Steelwork Contractors: Lewis Levin Architect (tensile structure & screens)
Central Welding Works (tree-column & general steelwork)
Mosaic Communications & Projects (tree-column & general
steelwork)
Detailers: KRU (Tree-column structures)
Lewis Levin Architect (Tensile structure & screens)
The winner in the Bridge Category was the Buitengracht Pedestrian Bridge in Cape Town, a project whose apparent simplicity belies the creativity and engineering ingenuity that it took to build it.
The judges considered the bridge, technically, a representation of excellence in the use of steel of the highest order.
The site was particularly challenging: the bridge is founded partly on top of a buried parking garage and partly on land reclaimed from the sea, which required some innovative thinking for the foundation design.
Having to integrate the bridge into a narrow corridor between two of the city’s main hotels and then to cross a five-lane highway also influenced the design outcome.
A structural steel asymmetric box girder was not an obvious choice of structural form, but it offered a number of specific benefits. The use of structural steel significantly reduced the dead weight of the bridge, which had to be four metres wide. A closed box section with an up-stand beam on one side enables pedestrians to access the bridge along its length. The lift shafts – providing access for the disabled – and additional access staircases could then connect directly onto the open side of the bridge deck.
The main challenge in fabricating a closed torsion box is the assembly and welding sequence and ensuring that all the required welds can be accessed. The team noted too: “Building a bridge next to the city’s two busiest hotels also meant that all construction activities had to be monitored continually to reduce dust and noise. The use of a prefabricated steel structure assisted greatly in minimising the construction impact.”
Buitengracht Pedestrian Bridge
Project Team
Developer/Owner: City of Cape Town
Architect: GAPP Architects and Urban designers
Structural Engineer: Vela VKE Consulting Engineers
Project Manager: Vela VKE Consulting Engineers
Main Contractor: Vusela Construction
Steelwork Contractors: ADM Engineering
The All Africa Games Athletes Village in Maputo won in the Light Steel Frame Building Category. The judges saw the Athletes Village as exemplifying a number of the advantages of LSFB, which enabled the project to meet very tight project deadlines and produce a high-quality end product.
In April 2009 Mozambique took over the hosting of the 10th All Africa Games from Zambia, which had been forced to pull out because of the global financial crisis. Consequently, Mozambique had only two years to prepare, instead of the customary four.
The judges noted that the most spectacular feat was the speed with which the project was completed. “The village of 27 four-storey buildings, providing 848 three-bedroom apartments, was completed in a little more than seven months! That’s one four-storey apartment building every eight days. This truly remarkable speed of construction could not possibly have been achieved with conventional concrete and masonry building,” they said.
The project team also highlighted that the framing system used incorporates innovative time-saving techniques, resources and engineering, which helped produce a quality structure on the scale required.
The Athletes Village housed most of the 6 500 athletes from 48 African countries who competed in the All Africa Games. It is now to be converted to residential housing.
2011 All Africa Games - Athletes Village
Project Team
Developer/Owner: COJA - Comissão Organizadora dos X Jogos Africanos
Architect: Mota-Engil, Engenharia e Construção, SA
Structural Engineer: Worthington Construction Group
Quantity Surveyor: Mota-Engil, Engenharia e Construção, SA
Project Manager: Michael Whitticar of Worthington Construction Group
Main Contractor: Mota-Engil / Soares da Costa Consortium
Steelwork Contractors: Worthington Construction Group, Cosira Group, Mema Metalúrgica
da Matola
Cold Form Steel supplier: Vela Steel Building Systems and Worthington Construction Group
Lining & Insulation supplier: Saint-Gobain
The world’s tallest steel headgear at Gold Fields South Deep Twinshaft Vent Shaft won the Mining and Industrial Category. With 5 000 torqued bolts – all fitted, innumerable welds – all passing the most stringent non-destructive testing, and minimal distortion in spite of all the welding, the overall fabrication quality of this project contributed significantly to its winning the award.
The completed structure stands 87m tall and has a mass of about 1 900 tons. It is the tallest steel headgear in the world and is expected to extend the life of the mine by up to 60 years.
The judges considered the structure “especially impressive for two main reasons: steel was the only viable construction medium that could satisfy the complex, constraint-dominated client requirement and, exceptional technical and project management expertise was required to execute the work successfully in accordance with these requirements”.
They also recognised this project as a great story for structural steel, as the material played a pivotal role in helping the mine to make its decision.
The project team explains: “Extending the height of the existing concrete headgear was not possible as its foundations were not designed to accommodate the additional mass. Since the existing headgear was still operational, destroying it and rebuilding the headgear was also not an option. The only viable option was to construct a new headgear from steel and erect it over the top of the existing headgear.”
The main framework consists of hollow-section structural boxes welded up from plates typically 45mm thick. The plates are welded together with complete joint penetration welds. Each 10m section needed two kilometres of pre-heated, submerged arc welding runs.
New headgear for Gold Fields South Deep Twinshaft Vent Shaft
Project Team
Developer/Owner: Gold Fields Shared Services
Structural Engineer: Hatch Africa
Project Manager: Gold Fields
Main Contractor: Steel Services and Allied Industries
Steelwork Contractors: Steel Services and Allied Industries
The Tubular Steel Category was won by the Saxon Hotel Skywalk, a walkway bridge that winds its way through the heavily wooded grounds of the Saxon Boutique Hotel in Sandhurst, Johannesburg.
The skywalk was constructed using 27 tons of tubular steel which frame its sleek, smooth, flowing lines.
According to the project team, the use of tubular steelwork for this project was a given due to its ‘strength-to-slenderness’ capability. “The brief was to provide an unobtrusive, elegant means for guests to move safely between the hotel and the villas while being able to enjoy the ambience of the location, and this was achieved,” they said.
The skywalk is fitted with timber flooring, glass handrails on both sides and a canvas roof canopy fitted to thin tubular rafters welded across the top chords of the bridge. It spans 76m from lift shaft to lift shaft and has five intermediate supports hidden in the forest.
As the skywalk curves horizontally and vertically along its length, it was impossible to fabricate its spiral ‘diagonals’ using fully rolled spiral tube. They were rolled in partial circular segments instead.
The judges said, “This project represents exceptional use of tubular steel as it snakes through the forest, seemingly unsupported, and at night it gives the impression of a fibre-optic cable floating in mid-air.”
Saxon Hotel, Skywalk Bridge
Project Team
Developer/Owner: Saxon Hotel
Architect: Len Lategan Architects
Structural Engineer: MVW Consulting Engineers
Quantity Surveyor: Brian Heineberg and Associates
Project Manager: SIP Project Managers P/L
Main Contractor: GIP Builders P / L
Steelwork Contractors: Impact Engineering Gauteng
Detailers: Precise Structural Modeling
Industrial Painters: Dram Industrial Painters
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