Studio: ARGE Negrelli
Authors:
10:8 Architekten GmbH - Architect, www.10zu8.ch
Conzett Bronzini Partner AG - Structural Engineer, www.cbp.ch
Diggelmann + Partner AG - Structural Engineer, www.dig-ing.ch

Zurich, Negrelli Bridge and the dense railway network. Together they emit a remarkable inviting charm, despite its cold industrial character. One term comes to mind - industrial warmth - dirty old town.

Is the bridge a place to be? Why not. A sunset on the bridge is just as spectacular as in the Swiss Alps. You just trade the mountain backdrop for a variety of concrete facades and the view of trains accelerating through the onset of dusk, as if trying to escape the darkness and catch up with the dissolving day.

INTRO
The two area developments Zollstrasse and Europaallee densify Zurich’s city centre along the edges of the railway track field. As a path across the open track area, the Negrellisteg provides unobstructed views and a superordinate orientation within the urban fabric. The Negrellisteg links the network of paths between city districts 4 and 5, while at the same time offering a unique opportunity to experience the crossing of the tracks as a brief pause for breath and a view against the backdrop of a remarkable urban panorama. The bridge is a further landmark in the track field, which emphasises its symbolic nature through its clear design amidst the flickering of the numerous railway installations.

SIGN BETWEEN BUILDIGNS
Both bridge exits set landmarks in the urban space. The lateral bridge brow is seamlessly integrated into the curved cheek of the spiral staircases: In this way, the fine bridge arch stretches to the foot of the bridge at city level and symbolically connects the two sides of the city. The gentle arch shape, which culminates in the centre of the bridge, reinforces the presence of the footbridge.
The sweeping curve geometry around the round lift tower formally frees the bridge walkways from the cubic boundaries of the neighbouring buildings. The result is the maximum open space that the urban spaces on both sides allow. The design language focussed on movement supports the unique position of Max Vogt’s sculptural signal box building.

TEXTILE BALUSTRADE
The parapet accompanies pedestrians continuously and on both sides. From the inside, it provides the necessary protection from the track, while strong end elements support the curved line of the bridge from the outside. A dense metal mesh is woven through the supporting posts between the two linear elements of an upper and lower chord. It gives the parapet a textile effect. The lift towers become light and visible cylinders in the space thanks to the fabric-like panelling.

DISTINCTIVE SUPPORTING ELEMENTS
The underside of the bridge - with a central girder - is continuous to the foot of the bridge in terms of the overall shape and load-bearing behaviour. While the spiral staircases assume a resilient function in the supporting structure, the lift towers are detached from it. The bridge girder is supported by two double columns, each of which relates to the wall flanks of the two descending railway ramps. Due to the increasing static height of the central girder and to ensure functional drainage, there is a slight incline towards the centre of the bridge. The flights of stairs open up to the urban space as much as possible as they widen downwards. The steps are kept flat and allow for comfortable strolling.

CONDUCTIVE LIGHTING
In favour of economical operation, the same lighting measure is proposed for the basic lighting and the «Plan Lumière». Thanks to the undulating shape of the balustrade, the light integrated into the handrail can alternate between inwards and outwards. The internal luminaire distributes the light asymmetrically over the walking area and thus achieves uniform illumination with warm light. The external luminaire has a grooved look and prevents glare for train traffic, but subtly illuminates the undulating parapet band in the evening hours.
An external grazing light on the lift towers also ensures a long-distance effect in the neighborhood and an overall harmonious light image of the footbridge.