Construction World March 2015

PROJECT PROFILE – STEEL CONSTRUCTION

The proposed structure was to have no concrete footings), and removable, should it ever be required – leaving minimal traces. It was clear that some steel structures would be the answer.

sarily round, from which would hang the viewing platform and hoisting structure. So, introduce a Toblerone profile compression ring at lower and upper levels of the roof. Attach the upper parts of the columns to the compression ring in a manner that would allow them to rotate in plan, make them also Toblerone in profile with curved upper ends (like those shoulder parts). Make the lower columns out of big tubes, whose final length and shape of the ‘dog’s leg’, which kink near their tops, and would be finalised on site after erecting the roof (on tempo- rary supports) based on the positions of the bases now drilled and welded into position. Excellent use of steel The detailing and fabrication of a tubular structure like this takes a special team. Spiral Engineering, the steel contractors on this project, is one of a few companies with the skill and dedication to build such a complicated structure. Project team • Developer: The University of the Witwatersrand School of Geosciences • Architect: Krynauw Nel Associates • Structural engineer: Peter Fellows Consulting • Quantity surveyor: Crane QS • Project manager: Craig Harrison PM • Main contractor: Omni Struct Nkosi • Steelwork contractor: Spiral Engineering • Detailer: KRU Detailing

The original brief: • The structure must protect the fossil bearing deposits from elements – particularly rain and falling debris and must prolong working hours on site for the scientists. • The structure must act first and foremost as a platform for research. • The structure must be able to accommodate tourism, or group visits of up to 48 people, but must separate these visitors from the research activity. • The structure must be able to lift rocks weighing around one metric ton The accuracy of the detailing and the dimen- sional accuracy of the fabrication was tested during a trial assembly on temporary supports (thus emulating the actual erection procedure) at a local rugby ground. Erection To reach the site, one has to cover the 7,5 km farm track road, which runs partly through a river bed. Special trucks with limited capacity were used on the farm. After four unsuccessful tries, finally a 30 ton all-ter- rain crane made it to site and had a long enough radius and capacity to reach without damaging the trees and the bush. Once the roof structure was erected on the temporary scaffolds and the upper columns were hung, only then could the final site-made dog’s leg kinks be done, leaving the beetle standing on its own legs.

and move these rocks to a vehicle loading point. • The structure must not have a significant foundation and be as close to free standing as possible. • The structure must not make contact with the ground within the anticipated 10 year excavation goals. The structure must be, due to the nature of the environment, temporary as it will almost certainly be there for many decades it must be permanent in nature (thus a temporary-permanent structural design). • Due to the sensitivity of the environment VIP visitations, the structure must be impressive when one is within it and reflect the importance South Africa holds for these World Heritage objects. • The structure must tell in its architecture the story of the site and the discoveries made there. • The structure must be fire and animal resistant. • The structure must be low maintenance. • The structure must be flexible for placement when on site. • The structure must allow for expansion of the excavation in the future. • The structure must be, where possible, manufactured in South Africa and use environmentally friendly materials where possible. the structure sits within, it must be as near as possible ‘invisible’ within the environment. • Due to the importance of the fossils it protects and the projected tourism and

27

• Cladding: Cupric Tectonics • Painter: Mzekizeki Painters

CONSTRUCTION WORLD MARCH 2015