Rising ocean levels and the near-ubiquitous response across design fields to solve this issue with an intervention to the urban fabric introduces a unique and topical design space. Should architecture combat or greet rising waters? Is flooding a disaster or source of beauty? Is waterfront property abandoned, or clad in durable materials?
The Ark proposes a reactive architecture that attempts to preserve urban fabrics at risk of flooding while simultaneously expanding and exciting existing spaces. The concept is simple. Create a bridge that expands under gravity when water levels are low, creating valuable public space; and folds closed under high tide water pressure, preserving passages of movement.
A protoype of the Ark is sited in Hamburg, Germany, a former industrial port city that still remembers the fatal damage of the 1962 North Sea Floods. The Ark in Hamburg directly connects the waterfront Elbphilharmonie by Herzog de Mueron with the developing mixed-use HafenCity project along the Elbe river, formerly separated by a large shipping port. The Elbe is tidally active and prone to flooding, with a differential in water height of up to 9 m from low tide to the 100-year flood condition.
The bending of the bridge is a promising ground for formal design. The central axis plunges towards the water while the edges rise towards the sky, mimicking gentle waves. Variations in profile enable access to the water for ferries and families at low tide, and as the waters rise, the bridge folds over the walkway in a protective embrace. Bending occurs primarily around the central axis, and as the bridge constricts, it becomes a sinuous curve in plan. Below, the bridge is loaded and structurally analyzed to form find and determine member forces (blue = tension, red = compression).
Complex behavior is enabled by an assembly of flexible parts and unique expansion details, raising construction to an art form. The primary ribs consist of kerfed laminated beams sandwiching a carbon fiber plate. The combination provides flexibility, rigidity, and the ability to lock extreme shapes as wood kerfs fully close. A tensile membrane is sealed to the carbon fiber plate edge, providing the necessary waterproofing. Wood steps at variable rotations are introduced on sliding dowels between ribs, offering seating and a variegated façade system.
Thus, the Ark is ready for its voyage, taking port in Hamburg and preserving the vitality and connectivity of Hafen City. Visitors and new residents can meander to the opera house and engage with expanded public space. The bridge reacts to water as people react to the bridge, and a delicate and shifting relationship between nature, form, and experience is established.