Construction World March 2015

PROJECT PROFILE – STEEL CONSTRUCTION

INGENIOUS Such was the quality of the steel structure at the Malapa Fossil excavation site, which was the overall winner and winner of the Association of Steel Tube and Pipe Manufacturers of South Africa’s Tubular category at Steel awards 2014, that Steel Awards convenor, Spencer Erling, was prompted to say: “It is surely the first time since I have been managing the Steel Awards process that the overall winner has INNOVATIVE, INVISIBLE,

ticked so many boxes as to why this project represents excellence in the use of steel.”

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The reason for the project

Design Architect Krynauw Nel says: “If we want to work with the environment, let it teach us its lessons. Bio-mimicry is the process of design where forms and processes found in nature serve as a design model. The design is inspired by natural site forms: leaves, insects and spiders and particularly by the Sediba fossils first discovered i.e. the clavicle and scapula. “Our proposed structure was to have no concrete footings (due to possible fossils in the ground), and removable, should it ever be required – leaving minimal traces. It was clear that some steel structures would be the answer. Tubular steel and bone motifs seemed an obvious match and circular sections could be curved to deal with site restrictions. “Particularly challenging was that final rock positions for the leg footings would only be identified during construction, prompting a solution in which legs could pivot and even ‘bend’ to accommodate these positions. This was a special solution that proved useful during construction.” The main structural element is the oval curved space-frame or ‘Toblerone’ truss onto which the roof is constructed and fromwhich

What is also known is that the fossils have been reliably proven to be about two million years old. Initial difficulties Built environment professionals are in some respects used to solving challenges that stand in the way of progress. And if ever a project presented obstacles to get underway this surely must rate among the toughest. The Cradle of Humankind is a World UNESCO heritage site. Before anything can be done in the area permission must be obtained from SAHRA (South African Herit- ages Resource Association). Even for something as important as this dig is, permission to disturb the ground needs to be obtained. Any develop- ment whether it is a farmhouse for a farm owner or a temporary cover over the dig needs a permit. The farm upon which the site is located is privately owned. Wits needed to put a land owner agreement into place which provided access to the researchers as well as permis- sion to erect a structure to protect the site itself. In this respect the landowners have been great supporters of the work being done at the Malapa site.

In 2008, Professor Lee Berger of the Univer- sity of Witwatersrand (Wits) was using Google Earth to look for possible fossil deposits in the Cradle of Humankind. What caught his eye was a near circular ring of trees, some- thing that would indicate a possible cave entrance or potential fossil deposit. While the full nature and extent of the dig have not yet been resolved, and might still take decades, what is known is that this is a significant find from a paleontological point of view. The site of Malapa has yielded two partial skeletons, a juvenile male and an adult female of a new species called Austra- lopithecus sediba . While there are several other sediba individuals from the site there are also remains of the animals that occurred alongside these remarkable hominids. From geological studies it is known that the cave roof (which has since eroded away) stood 30 – 50 m above the current deposit. Indicating that the hominids and animals collected in what is known as a ‘death trap’ situation. The animals would fall into the cave and then die on impact or not be able to get out, leaving behind full body remains.

CONSTRUCTION WORLD MARCH 2015

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