A Transformative Collaboration in Mixed-Use Architecture
The modernist tower of the Absa Precinct Building was constructed in 1970 and stands 140 metres tall – the 35th tallest building in Africa. In Johannesburg, with its rich history in goldmining, urban decay began to devour the city’s buildings in the 1990s. Many companies moved headquarters out of the CBD, some buildings were hijacked, or filled with squatters, and other buildings like this tower were mothballed. Rather than demolish or destruct, AMA Architects was called on by developers Atterbury and Divercity to give Towers Main a second chance – one that would make a lasting statement for the importance of urban regeneration in South Africa.
In the early 2000s, centres of artistic expression started to bloom, first with Newtown and the nearby Carr Street art and music scene, up to the present day with Maboneng, a vibrant new chapter for the art scene in Johannesburg. The building needed to link directly to these areas at a walkable distance, and so ‘Project Gloria’ was created — a rebuilding of the Absa Campus in the Johannesburg inner city. Towers Main was the largest structure in the campus, and required a transformation into a mixed-use building.
‘Project Gloria’ was framed around three key principles: Creating a successful workplace; attracting and retaining talent; and building physical and digital connectivity. The revamped building features ground-floor retail with a coffee bistro, modern business lounge, co-working office space, and an art gallery. Floors were re-envisioned and premium apartments were added. A sky garden made for a communal space, along with a ‘Village Park’ that activated public space, creating a new focal point for the Absa Precinct.
Towers Main is located to the South of the Central Business District of Johannesburg. It is nestled between two main road corridors that funnel traffic into and out of the city, to the East Rand, and to the West Rand of Gauteng. At the time of the project’s proposal, the city was in desperate need of suitable and safe mixed-use accommodation for all income levels.
AMA Architects committed to employing principles of successful mixed-use development to create a compact and walkable neighbourhood with activated street edges. By opening up the existing façade on ground level, livelier public spaces were created and movement across the site was improved, generating more interest and foot traffic for the retail stores through a connection to the well-developed Maboneng Precinct. The public space on the plaza and ground floor also introduces a pedestrian-sensitive, human scale to a previously vehicle-dominated environment, thus connecting people and places and encouraging public transport use. Urban furniture and ample landscaping offer an oasis within the harsh inner-city environment, while local sculptural art used throughout the space reflects characteristics of the local culture and identity. Opening the tower up at its base also reveals the grain of its inhabitants and simultaneously creates conditions through which the city can be appreciated from the tower.
For the residential façade, lightweight steel-framed panels were prefabricated to allow for 11 000 m² of ETICS façade to be completed within four months. The pixelated vortex pattern of the residential façade is a fresh urban addition to the Johannesburg skyline, bringing colour and vibrancy to it. It is reminiscent of the Johannesburg sky in the summer, full of clouds and colours.
Glass façades were also used which improved passive design strategies with regards to heat loss and heat gain. The residential façade was handled in a more economic manner, with the existing frame being kept and new glass with openings added as required. The internal walls were created using Hebel blocks, a lightweight autoclaved aerated concrete (AAC) which is a completely cured, inert, and stable form of calcium silicate hydrate. It is a structural material, approximately one quarter the weight of conventional concrete, composed of minute cells which give the material light weight and high thermal insulation properties.
SUSTAINABILITY, ENERGY CONSERVATION, & INNOVATION
Materials, design, and construction elements that reduce the building’s energy consumption were used, along with energy-efficient double glazing on the main and residential façades. The ETICS building system is also nine times lighter, four times faster to construct, and 12 times more thermally efficient than conventional brick construction. The Hebel AAC blocks’ enhanced insulation performance is five times that of brick of the same thickness. Used to build the residential inner walls, the thermal efficiency reduces the reliance on heating and cooling appliances and provides up to 60% reduction in costs. Because of the environmentally friendly and sustainable construction materials and techniques used, the Absa offices achieved a four-star rating from the GBCSA.