Schiffli bridge - Linking Man-Made Order and Natural Chaos

This pedestrian bridge over the Sihl River (near Zurich, Switzerland) is to provide access to a naturally forested hiking area. Existing buildings on one side of the bridge contrast with undisturbed vegetation on the other. Within this context, the bridge design is aesthetically pleasing, unobtrusive and easily recognizable as a functional river-crossing.

Design constraints are both environmental (flood, pedestrians) and architectural (aesthetics). Five design alternatives were investigated. A clamped truss framework over a span of approx. 37 m – environmental constraints disallow supports in the river – was deemed most aesthetically fitting and simultaneously cost-effective. The truss bridge consists of two loaded planes made of hollow steel sections, leaning slightly away from one another and fixed between concrete panels. The abutments are supported on micro-piles. Static and dynamic analyses were carried out on the truss, deck, abutments and piles in turn, and are described in this paper.

The construction procedure is complicated by the fact that only one side of the bridge is accessible to construction vehicles. The chosen construction procedure is described, as well as the cost and time allowed for the project.