The Green Point Educational Dome
The Green Point Educational Dome is the brainchild of Lindie Burskie from the City of Cape Town’s Environmental Management Department.
The first of its kind to be built in South Africa, this unique and impressive structure and surrounding gardens are the result of a significant contribution of trusted city contractors, including Derek Kock Architects, HHO Consulting Engineers, Terra + Landscape Architects and Entsha Construction.
The dome’s final design, manufacture and construction was completed Marks Engineering Works Association (MEWA) which specialises in the customised engineering of steel and timber. The dome’s various elements were manufactured in the MEWA factory in Darling and are being assembled on site in Green Point Park.
Almost all the materials used have been locally sourced; the timber of choice being South African poplar due to its hard-wearing properties. The poplar was sourced from the Karoo, cut to size and air dried.
Poplar is unique in that it gets harder over time and is an exceptional timber for curved laminated beams. To confirm its quality and mechanical properties, MEWA had the timber tested by the University of Stellenbosch’s Forestry and Wood Science Department.
The dome is made up of 20 8.5-metre laminated beams that come together in a massive ring of timber at the top. These beams are slotted into the centre timber ring with dovetail joints, each radiating outwards to align with the base brackets which are anchored into a polished cement base.
The top ring is a work of craftsmanship in itself, made from 20 concentric circular layers of poplar, with each layer being crafted out of 20 separate segments cross laminated to one another for strength. The beams are glued and jointed, bolted through the ring and finally bracketed to the centre ring.
The dome is unique in that the engineering methods and designs employed in its construction have been developed specifically for this purpose. No handbook or documentation exists on how to engineer and manufacture such a structure, which was prebuilt and preassembled in the MEWA factory.
One of its more unique aspects is the use of 16 three-dimensional concentric ring beams each spaced around 600mm apart and laminated to follow the curve and angle. These beams are the base mold for three-dimensionally curved marine ply.
While curving sheet material in two dimensions is common, curving ply in three dimensions has not been attempted on this scale before. MEWA developed a technique to bend ply in three dimensions and cross-laminate it for strength. This technique has worked well, and the ply will give the dome a perfectly shaped surface, alongside new timber engineering technology.
Steel sheeting on top of the ply will also be curved in three dimensions and will be fitted in a perfect spherical geometric pattern. This will look like a mosaic of brown tinted steel sheeting designed to resemble skins that would have covered a dome-shaped hut. These sheets are made from 3CR12, a unique South African product.
Substantial input by Grandi Manufacturing, a Cape Town-based engineering company, has solved many of the dome’s more complicated steel-related aspects. Three-dimensional gutters have been developed to blend into the steel sheeting and at the same time divert rainwater away from the doors.
A skylight molded from three-dimensionally curved 1 900mm glass will be the final roof on top of the centre ring and was also developed by MEWA.
The garden designed by Terra + Landscape Architects will be filled with timber sculptures, curved beam pergolas and floating benches with a garden full of plants to smell and touch.
The dome has captured the attention of six local and two international universities, numerous engineers, and architects from around the world. It has also garnered the attention of global government institutions seeking new engineering techniques for sustainable housing.
Technology, engineering, and manufacturing techniques have been carefully documented and photographed over time to make this information accessible.
Source: MEWA
