Mechanical Technology January 2015

⎪ Special report ⎪

The first LSFB McDonald’s outlet was in Goodwood, Cape Town and the entire shell of the building, including internal walls and exterior painting, was completed in two months. Roadworks and the installation of kitchen equip- ment took a further month, giving a total construction period of three months. A comparable double-storey building us- ing conventional masonry construction would have taken at least seven to eight months to complete. The Mining and Industrial category winner was the Bakubung Platinum Mine headgear. “This is a structure with thousands of bolts, all fitting without modification and tightened to specification, which is testimony to 3D detailing using Tekla and the accuracy of fabrication. What a pleasure to see and experience the exceptional quality and final presentation of the steel work,” said Erling. In the final award of the evening, the Rosh Pinah Zinc Corporation (RPZC) in Lüderitz, Namibia, won the Factory and Warehouse category for its zinc and lead storage warehouse, a 90 by 67 m building surrounded on four sides by buttressed concrete retaining walls. The challenge was how to sup- port the arch roof across an area that spans 65 m using steel that could be fabricated and erected in Lüderitz, well known for its strong onshore winds and corrosive environment. Square hollow sections (SHS) for all the truss members were the natural choice for reason that included: ease of fabrication; internal members can be cut by saw; no special developments are necessary for connections; the perimeter of the SHS is big enough to permit straightforward fillet welds for end connections; and, by keeping the members straight, the curvature for the roof can be created using different purlin lengths. In addition, no wasting of top and bottom chords is incurred as would happen had the members been curved; and tubular profiles are ideal for dealing with the prevailing winds. Erling says that each year the ability of South African architects and engi- neers to build aesthetic steel structures becomes increasingly apparent. “The quality of the entries improves each year and 2014 was no different. I con- gratulate the winners and all those who entered,” he says. q

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ronmental costs. Structural steel was chosen as the ideal material to prove the above and the inaccessible, deep gorge provided the ideal situation for the engineer. The final design consists of four suspended cables supporting a row of steel Y-frames, which in turn support a 1.2 m steel deck, with the suspension portion of the bridge structure consisting of two equal spans of 60 m. The Corporate Office Building cat- egory was won by 30 Jellicoe, a building situated in the heart of the Rosebank CBD. The judges said that the slenderness and proportion of the tapered tubular steel columns give the building an elegant aesthetic that sets it apart from its neighbours. “The ripple that is created by the louvre blades adds another level of detail that finishes off the overall concept,” they reported. In the light steel frame building (LSFB) category, McDonald’s was declared the winner for its entry of seven fast food outlets: Goodwood, Rustenburg, Silverlakes, Somerset West, Epping, Tembisa and East London. These buildings not only displayed excellence in the use of light steel framing but also clearly demon- strate why 500 000 m² of LSFB floor area has been built in the past year. McDonald’s chose LSFB because it could meet its energy efficient building goal and because speed of construc- tion is one of light steel framing’s main advantages. By using LSFB McDonald’s not only reduced material waste by 30% and transport costs by 80% but also the insulating layers reduced the building’s energy requirements by 17 to 20%, compared to conventional building designs.

1. The Malapa fossil excavation site took top honours at the Steel Awards 2014. 2. The Waterfront Silo Development, Architectural category winner, used struc- tural steelwork to provide slender support to the facades, walkways, bridges, lifts and feature stairs. 3. The Tugela River Pedestrian Bridge (KwaJolwayo), Bridge Category winner at the Steel Awards 2014. ning the heritage silo and buildings constructed in the 1920s was a great challenge to the structural engineers and contractor. No.1 Silo has been awarded a six- star rating by the Green Building Council of South Africa and is the country’s lat- est and largest green office building. It is only the second office building to be awarded this rating in South Africa and the first in the Western Cape. In awarding the Tugela Pedestrian Bridge the top spot in the Bridge cat- egory, the judges agreed with the project team that this bridge “merits an award in view of its portrayal of the benefits that technical solutions and efficient design using structural steel can bring to rural communities.” This 134 m structural steel suspen- sion bridge over the 8.0 m deep Tugela River at KwaJolwayo, upstream of the Tugela Ferry in the Msinga area of rural KwaZulu-Natal, has resulted in a life-changing, safe crossing option for communities on both sides of the river, enabling them to access commercial and educational opportunities that were previously inaccessible, particularly dur- ing the summer months. The design focused on the fact that the lower the mass of a structure, the less material is required, with cor- respondingly lower capital and envi-

Mechanical Technology — January 2015

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