The staircase is located in a restricted space which led to a cylinder shaped geometric design, comprising a central stainless-steel lattice drum supporting the steps and the landings made from Ductal® organic fibre ultra high performance fibre-reinforced concrete. The pre-fabricated fibre concrete parts were assembled on site through local pre-stressing which enabled the mechanical and geometric continuity of the stair string to be reconstituted A set of parts forming the exterior fittings complete the layout and make the system globally stable.