Tata Steel’s Celsius® 355 elliptical hollow section was chosen for the bracing at NEO Bankside, a striking residential development in Southwark, London.

With echoes of the ground-breaking design for the Pompidou Centre in Paris, the four apartment pavilions at NEO Bankside display their structural steelwork on the outside. More than three hundred lengths of 200 x 400mm elliptical hollow section crisscross the building façades in a regular, diagonal pattern.

The ‘diagrid’ bracing is repeated on the same scale across the four apartment pavilions. Two of the pavilions stand at 12 storeys, a third is 18 storeys high and the tallest comprises 24 storeys. The buildings incorporate 217 apartments and penthouses along with triangular-shaped, enclosed winter gardens at each storey level. The diagonals of the steel bracing link the four buildings visually in the vertical plane. They also mirror the geometric ground plane of the pavilions which are constructed in the shape of elongated hexagons.

The decision to use elliptical hollow section for the steel bracing was prompted by aesthetics and considerations of structural efficency.

There was another very important reason for choosing elliptical section. The external steel bracing plays a crucial, structural role - enabling much more freedom in the interior layout of the apartments because it reduces the need for fixed, internal shear walls.

All of the lengths of Celsius® 355 elliptical hollow section were treated with epoxy micaceous iron oxide primer and coated with an acrylic urethane based architectural finish on site.

Each set of four bracing members radiates from a central fixed spindle, with each member terminating at a node embedded into the floorplate. Tata Steel 323.9mm Celsius® 355 circular hollow sections up to 16mm in thickness were used in the spindles. At ground level, the elliptical hollow sections are concrete-filled to resist impact.