Money Zone is a structure of angles, folds and hidden spaces, a piece of origami made solid with steel and fabric. The only way Aran Chadwick and his team at Atelier One could fix the engineering was to design it as a three dimensional card and pin model.
'The architect wanted a ribbonscape with folding plates defining your route and creating unusual private spaces,' Chadwick explains. 'We could not have done it in two dimensions.
'The computer model was of a folded plate creating a ribbon which had no form or reality. But we did get node points and details of openings in the floor slabs. So I used that information on a model to position some fins and started to weave the ribbonscape.'
The result is a steel bridge which leads into a braced stiff box core to make the boundary of the Zone rigid. Triangular flying struts rise to the 8m high prow, echoed by random flying struts that tie back to nodes, creating the shapes the architect wanted.
As the steel strut lengths all differ and no two triangles are the same, Chadwick assigned each an individual indentitfication 'so you could build the Zone by numbers'.
Construction of the Money Zone was split into two phases. The flat slab concrete foundation and lower level steel up to 6m was done by William Hare using standard sections and full capacity connections. The much more complex upper steel was handed to Westbury. 'The model was really valuable for this,' says Chadwick, 'as we could explain how the structure works.'
Steel sections varied from 25mm diameter to 80mm diameter solid round sections, with 114mm CHS colums. Lengths ranged from 14m in the core down to 6m. Detailed drawings of each node connection were made to help the contractors put everything together. The fabric shapes for each panel were all different too. 'You could create the fundamental pattern but before the seams could be stitched Landiel needed to measure the steel (It's a bit like fitting a wedding dress),' Chadwick explains.
The only stomach-clenching moment came when Chadwick discovered just how close the prow of his design came to the cables of the Dome itself. 'We squeezed in by just 200mm,' he says.
Sponsors: City of London Corporation, De Beers, Royal Mint
Architect: Bob Baxter
Project manager: Fraser Randall
Engineer: Atelier One
Architectural steel: Westbury Steel
Other steel: William Hare