Hängemattenbrücke (Hammock Bridge)Design, 2017
The proposal for Hängemattenbrücke, completed Digital Structures researchers, simultaneously achieves two design goals for a span across the Spree River in urban Berlin: connecting the bordering neighborhoods in a way that encourages efficient movement between Brommystraße and the East Side Gallery, while also creating a public space for gathering and viewing the river in addition to crossing it. The design accomplishes both objectives by recalling the history of the site, referencing an existing pier, and reinterpreting the historical concrete arches of the original bridge with an updated structural system.
In reconnecting the neighborhoods and replacing the functionality of the existing viewing platform, the bridge itself becomes a place of both movement and stasis, where pedestrians can cross on the way to the train, or pause and relax on the informal amphitheater and rebuilt pier deck. The cables of the bridge compare visually to the lines of a hammock—for the most adventurous pedestrians, the configuration offers the opportunity for lounging on the cables themselves, with the assistance of a fine mesh.
The structural system of the bridge takes advantage of its natural curvature in plan, while expanding on an idea pioneered by Schlaich Bergermann & Partner that relies on three-dimensional forces and a mixture of tension and compression. Hängemattenbrücke is a cable-stayed bridge, but the single pylon leans away from the deck, and the main cables stretch both horizontally and vertically rather than simply hanging, as in more conventional cable bridges. The cables attach to the inside of the curved deck, while the rest of the bridge cantilevers out from these supports. When tensioned, the cables pull the deck both up and in, which causes arching action to develop on the inside of the main bridge curve, which is thicker than the outside to take the compression. The amphitheater tapers in concrete from the two arches towards the main path of the bridge, and the deck continues this taper out towards its free edge in steel.