Construction World March 2015

PROJECT PROFILE – STEEL CONSTRUCTION

The structure also has a steel viewing deck capable of taking a maximum of 33 people. It is suspended from underneath the lattice girder and the roof using steel ties.

Innovation “The main body is very slender and was constructed from an oval shaped lattice girder, connected to the top of the eight legs and supporting rafters that span out from a central point of the roof. The top of the struc- ture is 11 metres above the ground,” says sructural engineer, Peter Fellows. “The structure also has a steel viewing deck capable of taking a maximum of 33 people. It is suspended from underneath the lattice girder and the roof using steel ties. A hoist is suspended from the viewing deck in order to assist in the removal of fossils from the site,” he continues. “The legs supporting this structure are connected using hinges allowing them to swivel horizontally. This is important as the exact location and level of rocks used to found them could not be determined at the design stage and were only determined once on site. The upper legs branch outwards at an angle and connect to a plate and then to a lower leg standing at a more vertical angle, creating a bend that resembles a ‘knee’”. Engineering The final shape, when viewed from above, is like a beetle with eight legs. It was decided that during construction, once positions were chosen, rods would be drilled into rocks around the site onto which would be welded base plates. That of course requires that the eight columns are adjust- able to suit the positions once identified. How was this achieved? The roof was to be ‘rondavel-like’ in shape but not neces-

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Themain approach walkway is slightly raised above the site but handrails are omitted in the main to facilitate movements of animal species over and under the walkway. “From the viewing platform, visitors will walk on the suspended walkway while being shown the excavation and education- about fossils, the site and the structure. The ‘suspended-from-the-roof-solution’ makes it possible to bring visitors much closer to the excavation than with more orthodox walkway solutions,” says Nel. Although it is envisaged that the struc- ture would remain in use for several decades, total removal would be possible leaving only a minimal footprint on the site. Changing seasonal colours are consid- ered and the bark-coloured structure will sit comfortably in both lush green summer and winter Highveld khaki. The unexpected white interior enhances natural light; aided by a small skylight.

“With stainless steel and chrome details, this creates a ‘modern laboratory’, while contrasting to – and visually illustrating – the economic simplicity of the main structure,” explains Nel. The on-site construction period was reduced by designing and manufacturing the structure in separate parts that could be erected for a trial period and testing off-site, dismantled into the eight legs with a section of the main truss attached, and then bolted together again on site in the eight pieces. “The rights of the environment are becoming increasingly important on an ever densifying and populated planet. Architects have to stand up for the environment and through actual buildings illustrate the possi- bilities of minimal impact on pristine sites. “This may be one of the most impor- tant contributions this structure can make,” he says.

CONSTRUCTION WORLD MARCH 2015