Awards

Earning a commendation at the Concrete Society’s 2019 Fulton Awards, the building achieves architectural and engineering accomplishment in concrete design and detail as daylight streams into the large open plan offices from the exterior and through the 5-storey atrium between the two wings of the building.

This feat was achieved through the creative and environmentally friendly use of concrete. To minimise the impact of concrete manufacturing on the environment, the team used a reduction of ordinary Portland cement content throughout all concrete in the building. The architecture would not have been possible without the use of concrete and extensive workshopping by the team, resulting in a modern, functional and impressive new building. The economics, versatility, strength and durability of concrete, together with the available skills in the construction industry, makes concrete as a construction material a natural choice.

However, selecting concrete as a material for feature elements takes this choice to the next level. Concrete not only adds to the natural strong base required in the architecture but also exhibits the architecture in a more economical and durable way by means of managing the finish and crack control. The durability of concrete will allow for lower future maintenance costs while the versatility allowed flowing patterns to be created cost effectively. The cost-effective use of concrete as floor slabs and for shear walls and its characteristic resistance to seismic events are well document, hence it needed no additional motivation as the building material of choice. In addition to the above, developments in concrete mix designs over the last few years have increased the environmental consideration of concrete use, specifically relating to incorporating slag in the concrete mix. The concrete contained a high slag content, which is a by-product of steel production, is used to ensure the durability of the concrete and limit early thermal shrinkage/cracking of the concrete.

Special care was taken with both the mix design and the construction procedure. Pour breaks and construction joints were carefully considered to mitigate the impact of shrinkage and the erection and installation sequence of the construction. Casting of floor slabs was mostly scheduled to occur in cooler temperatures during late afternoons and early evenings to assist in reducing the effect of heat and cold on materials (thermal effects). Given that the construction took place as the City of Cape Town was experiencing a drought, snagging was offset using a combination of curing compounds, wet sand and hemp sheets for vertical members.