The backbone of a whale may sound like a strange place to draw inspiration for a spiral staircase, but nature often features forms that have evolved well to fit certain purposes (or porpoises, if you’ll pardon the wordplay).
Andrew McConnell conceived of this system as a modular set of components that can be deployed in a spiral, each element supporting the next – the only variation would occur in the top and bottom pieces that connect to landings.
And while the pieces may look (and be, for that matter) three-dimensionally complex, this is the age of 3D printing, and creating something repetitive of this kind could also be done using molds.
From the designer: “Inspired by the spine of a whale, the Vertebrae Staircase is not simply mimicry of organic form but an exploration in shaping structure. Much of the design work went into refining the single component, or vertebra, that mate with each other creating a unified spine running from floor plate to floor plate. These interlocking vertebrae provide a rigid structure for the steps, railing and its users. And the railing is reinforced by connections that help the staircase resist rotational forces caused by the cantilevered steps.”
“The outer surface is composed of multiple layers of a durable composite fibre material while inside are the key structural elements. The vertebrae are mated using steel fittings and locked together with steel pins. When all the connections are made, continuous structural spirals run through every vertebra at the hand rail and beside each step, reinforced by structural foam and a network of steel rods. “
“Steel plates connected to the slightly modified base and top vertebrae are anchored to the floors. Beyond this, there are no hidden supports as the Vertebrae Staircase is designed to act as one structural element, bearing the loads of its users and transferring these forces to the floor plates. And the pinned connections at the floor plates combined with the connections between vertebrae allow the staircase to successfully resist twisting and rotational forces that result from the cantilevered spiral and cantilevered steps.”