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The Living Staircase is a dramatic centrepiece for the newly-refurbished Ampersand Building in London’s Soho district. This 12.5m high, 5m diameter spiral stair is unlike any other, designed by artist Paul Cocksedge with structural engineering by Arup.
Paul Cocksedge’s vision was to offer a lush and calm environment for reflection, reading, impromptu conversations and small meetings as well as a home for hundreds of plants. – In response our structural engineers developed a design that removed the central, load-bearing pillar allowing for the creation of three circular spaces within the stair itself.
Structurally, the staircase has a 5m free cantilever from the edge beam of the three floors that open onto the stairway within the atrium. Constructed of steel and clad with a thin oak overlay, a back span located within each floor supports the stair, allowing the staircase to appear as a pure sculptural form with no obvious means of support. The balustrade is home to hundreds of plants, including herbs that can be picked by staff and used to make herbal teas.
The design brief called for a staircase that could provide more than just a means of moving from floor to floor. The result is a stair unlike any other.
A primary challenge for our structural engineers was the need to minimise vibration effects resulting from footfall. We deployed specialist in-house tools and software to analyse the human-induced vibration impacts of a series of design options.
This led us to develop a design featuring a hollow section formed from the soffit plate and stair riser, stringer and stair-top plate. The hollow section provides sufficient bending and torsion stiffness to maintain low vibration effects, whilst also being tapered in sections to give as thin and light an appearance as possible at the exterior edge.
