Les Cèdres Footbridge in Chavannes-près-Renens over the Geneva-Lausanne Motorway, Switzerland

<p>The pedestrian and bicycle footbridge of Les Cèdres, at Chavannes-près-Renens (Switzerland), crosses over the A1 motorway running along the northern shore of the Geneva Lake and connects two highly developing districts located in the west part of Lausanne. The footbridge is in addition conceived to improve the urban landscape and to represent a new landmark. Its structural concept aims at minimising the visual impact and allowing for a fast construction sequence, with the lowest possible interference to the motorway traffic. To achieve these goals, a slender arched-shaped frame was built, with a rise-to-span ratio equal to 1:16. The structure is constituted by a main span and two lateral spans, leading to an integral footbridge with a clear distance equal to 56.50 m between pier bases.</p><p>This paper aims at describing some relevant features of the structure and its construction, and a synthesis of the secondary elements which have required a thorough analysis during the design and construction phases. It also explains the evolution from the original design of the competition (a stress-ribbon) to the actually built structure. Some considerations on the dynamic response of the structure are finally presented.</p>