Attractive crossing

Through the centre of the Wallonian town of Verviers in the Belgian Ardennes winds a small river, the Vesdre. There are bridges, but they are quite a long way apart and when a new shopping centre was built, an attractive footbridge was needed between the high, steep banks.

Architectural studio ZJA produced an unusual design to meet this apparently simple need. Part of the task was to make a direct connection between the low riverside walkway on one side and the high walkway on the other, rather than simply linking the riverbanks on one level. It might seem obvious to cross the 25 metres with three separate bridges, one of them performing the function of a flight of steps from one level to the other. This design by ZJA is radically different, however, since the footbridge is a single composite sculptural body, self-supporting and completely symmetrical, making four connections between the banks. It does so in a way that is clear and light, without being massive in volume.

Four decks, one load-bearing structure

The footbridge can best be described as a single whole with two horizontal decks, one above the other, and on either side paths like staircases linking the high and low riversides, one high on the south bank, the other high on the north bank. What is exceptional is that all these decks are connected in one and the same load-bearing structure. This is made possible by the use of 40 differently shaped steel frames, which spread the forces across the symmetrical whole. In keeping with the walkways and a landscape known for its high-value rock, the steel bridge is dressed with natural stone.

Parametric design of unique frames

Seen from a distance, suspended above the water, the footbridge looks like a cross between the skeleton of an extinct giant animal and a scene from an Esscher drawing, with decks and steps weaving past each other. Its symmetrical character, its surprisingly lightweight structure and the light that plays through the cut-away volume make it a visually attractive object. Moreover, crossing the bridge is a remarkable spatial experience. Those using the steps on either side in particular are presented with a view of the water, the banks and the body of the bridge that changes with every step. You make your way through a small structural miracle.

The elegant and intriguing image created by the footbridge is the logical consequence of bringing together functional demands and a structural principle. Every element has been separately designed for its position and function in the whole, and adjusted in its shape and volume accordingly. The distances, the orientations, the sizes and the forces at play each find their optimal form in this design. A perfect synthesis of image, function and structure. This is made possible by the parametric design of the 40 unique frames, each of which takes the lightest, strongest possible form for its position, giving the bridge its unique but symmetrical and natural shape.

Architect: ZJA
Engineer: SBE
Year of design (not built): 2010

Project: #640