Subtle symbolism
The symbolic character of the building can be seen from the air: the photovoltaic panels on the roof and the layout in plan of the upper three office storeys form the shape of a stylised dove of peace. From the viewpoint of a visitor on foot, the rounded contours of the building and its curving facades make reference to the undulating movements in sports such as free-style snowboarding. The most spectacular symbol is not accessible to the public but forms the linchpin of the employees’ interaction and communication: the centre of the building opens into a 16 m diameter atrium in which a circular staircase links all five storeys together. Looking up from the bottom, the undersides overlap one another like the five Olympic rings. The timber-clad hollow box steel girders were craned in three segments into the atrium space, where they were site-welded and connected to the circular steel beams along the floor slab edges.
To prevent smoke from rising into the atrium in the event of a fire in the floors below, hardly visible acrylic glass smoke curtains are attached below the ceiling slabs. By installing a fire detection system and sprinklers, the fire resistance requirements could be reduced from R 60 to R 30.
Maximum flexibility
The building services equipment with cooling and heating ceilings is modular and based on a 0.90 × 0.90 m grid, which is apparent from the ceiling layout. Nine of the ceiling bays arranged in a square give a grid module of 2.70 m, based on which partition walls can be flexibly repositioned. However, an orthogonal column grid is nowhere to be seen: in the centre of each of the four wings of the building, a cylindrical reinforced concrete core carries most of the vertical load and stiffens the structure. 194 columns per office storey run along the double facade at 1.35 m centres. The columns are inclined parallel to the slope of the external glass panels, which is a maximum of 30 degrees outwards or inwards. This means every column has a unique geometry. The fire engineering calculations were complex because the columns were to be left exposed to view. Most of them consist of hollow steel sections that were, in some cases, filled with concrete. Others are made from solid steel sections. Despite these differences all the columns look the same.
