Architect and Builder April 2017 | Page 30

Bridging the expansive, vertical volumes of Rosebank Towers’ three main atria, the sculpture - Transpiration I - echoes the organisational structure of the building pedestrian access through an inviting multi-volume entrance atrium. This five-storey street entrance atrium contains the first line of security in the form of a security desk which deals with both vehicular and pedestrian access. After the first security line, pedestrians take the shuttle lifts to the two main atria which distribute people to the different major tenants. All of the building’s entrances are mobility-impaired accessible, ensuring principles of universal access are carried throughout the building fabric. Vertical Circulation In section, the building comprises eight parking floors (one basement and seven above ground), one retail floor housing a popular gym well used by visitors and building occupants alike, and seven office floors. Once people have entered the building either via vehicles or on foot, they then travel up to the offices above. A separate lift lobby is provided for access to the gym floor. A feature set of glazed shuttle lifts transports users of the building, stopping at the street entrance lobby, all visitor parking levels, and the two atria levels of the building. The atria offer generous waiting areas at the points of departure from the scenic shuttle lifts that complement the energy of the movement of people up and down the building. The Atria Rosebank Towers is a multi-tenanted building, with two human-scaled office atria at different levels mediating between arrival, visitors’ common areas, and working spaces. The first four-storey multi- volume atrium sits nine floors above the street level, overlooking the Johannesburg and Rosebank CBDs and giving access to the first group of tenants. A further smaller three-and-a-half storey atrium, also with spectacular views, is stacked above, giving access to the higher floors’ tenant. The shuttle lifts stop at the bottom of each atrium. The building’s H-form is designed around the atrium space supported by the two courtyards. The central core of the building sits in the middle of the H-form, and houses lifts, stairs, service risers, and ablutions. From the street below, the glass link of the entrance atrium presents itself as a threshold to the views into the spaces beyond. The southern exposure ensures 30 that the atrium will never be over-exposed to sun, and can therefore have clear glazing overlooking the street and to the Johannesburg skyline beyond. This façade emphasises the open nature of the building to its surroundings. At the ground level of both atria, a canopy of trees mediates between the activity at the ground level and the open collaborative spaces on the office floors above. This vegetation brings an organic softness to the structured environment around it, and establishes a sense of a peaceful and productive environment around, that is in tune with the leafy neighbourhood of Rosebank beyond. Detailing in the bridges, balustrades, and the scale of material choice such as the timber backdrop of the reception, further enhance the feeling of belonging in a people-centric and appropriately scaled space. The Courtyards The main morphology of the building from the office floors and higher is an H-shaped configuration with wing depths of up to 12m in order to gain as much natural light as deep as possible into the floor plates. This configuration creates two open courtyards between the east and west wings of the building. The west courtyard will have long views all the way up to the Northcliff water tower. The indoor planting at the heart of the building and the external courtyards acts as a green lung to the building. It provides a space for contact and integration, and ensures that nature and a direct relationship with the environment is prioritised at the centre of the scheme. The Office Floors The office floors are organised around the central core and the open atria spaces. The lift bank is centrally located ensuring that