The design for a new footbridge over the Rhine ties in with the intention of creating a park spanning both banks of the river. It will be located in a “Parc du Temps” where a key feature is the continuous circular pathways.
In keeping with the variety of pathways through the park, the footbridge design is for two bridges. It will lead the visitor in several directions, to the river-side route at one end or the higher ground at the other. There is also a resting and meeting point - a balcony overlooking the river.
Having decided on the dual footbridge approach, the task was to create a sufficiently rigid structure whose mass was compatible with the required span.
Very narrow decks (4 and 3 meters) form the covering of a variable beam (whose section changes) stretching almost 12 meters at the centre between chord and arch of each footbridge. This device provides sufficient stiffness to an otherwise excessively narrow deck, allowing it to withstand dynamic foot-fall stress and wind forces for a span of some 130 meters.
The curved profiles of the two separate decks lie on different planes. They are linked by a series of diagonal struts and tie-rods to form an “open” beam that does not block the view of the river.
The walkways have a cement flooring which acts as ballast for the whole bridge, offsetting any brusque movements from dynamic or asymmetrical loads. It also provides an essential non-slip surface for this damp environment.
The slender piers create no separation between the river and the sky. The equally slender lines of the two rounded decks crossing the river seem to pull sky and water into their gravitational fold.