genstorf-windisch footbridge, gebenstorf, competition

project owners:

gebenstorf and windisch councils

programme:

pedestrian footbridge

dates:

competition 2020

collaboration :

dr. lüchinger +meyer bauingenieure ag, zürich

integration into the site

The site is marked by the strong presence of the hydroelectric installations that have shaped the place and provide a spectacular multi-sensory experience: the impressive sight of the mass of water, the deafening noise of the waterfall and the coolness of the spray coming from it.

The footbridge closely related to the site and is integrated into the hydroelectric setting by the use of its language codes: repeated massive concrete piers connected by a long, lightweight metal deck.

On the north bank, the former Spinnerei factory buildings, from which the bridge takes its name, form the most prominent built environment around the bridge. The green space with its gazebo offers walkers a transitional element between the urban environment and the natural surroundings of the river. 

Location

The layout of the new footbridge is slightly modified to fit the context more effectively

On the north bank, the abutment is moved westwards compared to the existing bridge, freeing up a dedicated space around the protected gazebo, allowing it to express its full merit and enabling the footbridge to connect smoothly to the wooded park.

On the south bank, the footbridge is naturally located at the foot of the access road (on the existing bridge site), leaving the lower passageway free for the boats of the pontoon boatmen.

The arrival points on the banks have been raised due to flood levels, and the footbridge spans the riverbank walls to get support just behind them. The continuity of the existing walls is restored, thus offering a clear distinction between the built elements and their corresponding periods.

User experience

The footbridge provides a fast, functional route for pedestrians and cyclists... but not just that!

Different areas are created to offer a more rewarding experience to those users who take the time to appreciate the place. The two massive piers provide small spaces where people can sit in the middle of the river and enjoy the water show in peace. On the island, the riverbank has been upgraded with small urban amenities (benches, picnic areas, etc.) to give passers-by the opportunity to stop and admire the site from this magnificent wooded area.

Structural design

The footbridge structure has been designed to disappear into its surroundings, with no visible structural elements above the walkway level permitting a sweeping view of the surrounding area.

Like a springboard, the footbridge curves in its centre and rests on massive piers which is reminiscent of the hydraulic structure facing it.

The load-bearing deck is a very slender steel structure, with a static height of 1/75th of the central span, and with side edges bevelled downwards to minimise its impact.

The structure's thinness is made possible by integrating dynamic dampers in the deck to limit the movement of the footbridge. This ensures user comfort and greatly reduces the amount of steel used in the structure.

Materials

The massive, stone piers are similar to riverbank walls. Their massiveness is a bulwark against the river's caprices and the impact of tree trunks.

Despite its lightness, the footbridge is delicately curved and made of steel. Its anthracite grey colour, and its marked contrast means that it disappears into its own shadow.

The railings, made of thin galvanised steel tubing, give a high degree of transparency to the whole.

The asphalt surfacing creates an optimal riding surface for cyclists. 

Light

The stopping points located on the piers are intermittently lit by a street lamp, making this friendly, unusual spot stand out from the traffic lane as a pace offering peace and rest.

To minimise light pollution on the river, the footbridge is lit only on the downstream side, with an LED ribbon below the handrail directed directly towards the carriageway.