Office Buildings, Business Parks

RAS Architects

Location: Cape Town, South Africa
Site Area: 3 500m²
GBA: 62 000m²
GLA: 40 000m²
Storeys: 47
Architectural Height: 192m
Market: Commercial, Hospitality

Cullinan Square

Located on the high-profile Site D, this tower is a design study of a mixed-use, high-rise development in the heart of Cape Town’s new business district. For this design study RAS Architects collaborated with structural engineers for the design of the tower, which at 47 storeys and 192m would be the tallest building in Cape Town and mark a shift from traditional development patterns in the country.

The design is highly efficient, both in terms of floor space and wind resistance, while including spectacular views of the ocean, city bowl, Table Mountain and the wider surroundings. The tower design is complemented by its ground level interface which focuses on public interaction by using only a third of the area for the footprint of the building. Surrounded by the barren facades of monolithic buildings, the rest of this city block provides 2 400m² to preserve the heritage of the site and encourage pedestrian traffic. A super-basement hidden below the virtually undisturbed ground level offers the desired parking bays, while also addressing the promise of a less vehicle-centric future where technological advances will reduce parking requirements and leave lettable upper-level parking floors unused.

The orientation and shape of the tower was generated to deal with the prevailing winds in an economic manner, whilst orienting the larger facades toward views of Table Mountain and the ocean. By limiting the surface area of the tower that faces the critical south-easterly wind and reducing the drag coefficient with an optimised building shape, the reinforced concrete core is smaller than typically expected in a tower of this height, reducing structural costs and increasing the GLA of the development.

A mixed-use development is proposed to promote public activity and diversify economic risk. The hotel component occupies the highest part of the tower, offering unparalleled views from each room, the sky lobby, restaurant, spa and observation deck at the top of the building. The ground level retail component promotes public activity and acts as an economic boost for the development. In addition to pedestrian access, the retail component is also supported by the basement parking levels, nearby public transport hub, surrounding office buildings, and the 20 levels of prime office space in Cullinan Square.

The proposed tower’s architectural height and slenderness ratio would make this the first skyscraper in Cape Town to comply with the modern definition of the term. The design showcases RAS Architects’ vision of how tall buildings in South Africa can be efficiently designed and result in visually appealing solutions that simultaneously address practical and socio-economic factors.