Construction World June 2019

The precast option allowed WBHO to manufacture the precast panels off site while in-situ concrete work was progressing on site.

The building is an expression of concrete, glass and timber with concrete being the primary element in both the finish and structure.

A total of 501 precast panels at a rate of 23 panels a week were manufactured, including window sills, flat external panels, external corner panels, patterned panels and capping panels.

all raw materials had to be stockpiled ready for use, with fly-ash and slag stored separately. The advantages of designing Norval Foundation with a precast concrete façade were many, including the flexibility of shape and form, and the variety of surface finishes which could be achieved. In terms of physical properties, concrete offered durability and low maintenance while providing good insulation against sound and resistance to fire. The precast option – in addition to speeding up the building programme – also allowed high levels of quality control and consistency in the finish; there was also no need for façade scaffolding. The precast panels went through a rigorous design process of testing and sampling in order to achieve the desired finish. To ensure that the precast concrete method was optimally applied, it was important that the right material was chosen for the patterned moulds, and that the correct stripping oil was used. The substantial weight of each panel was a challenge in terms of moving and placing, requiring the use of special lifting equipment. Panels would need to be cleaned of oil stains to ensure a consistent finish, and the edges of the patterned panels also sometimes needed to be repaired. The building is situated in an elevated position, shielding a wetland and creating a private space for a The Sculpture Garden. This wetland is one of the last known breeding sites of the Western Leopard Toad, an endangered species that is endemic to the area. The linear circulation spine of the building is positioned between a busy road and the wetland, with the galleries and public spaces facing the natural landscape and capturing framed views of the wetland, vineyards and mountains beyond. The triple-volume atrium creates a deliberate visual connection between these zones – one urban and the other natural – and provides a physical transition between these contrasting environments. 

AfriSam was the supplier of choice for all the concrete requirements for the precast as well as other structural elements.

A total of 7 500 m³ of readymix concrete was used for the Norval Foundation building.

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CONSTRUCTION WORLD JUNE 2019