Motorway N4/N6, Schaffhausen

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Between Bietingen and Herblingen, the north-south national highway connection N4-A81 has a gap. The two-lane city bypass through Schaffhausen already reaches its capacity limit during peak hours. The high traffic volume demands an expansion of the motorway and consequently a widening of the traffic area within a densely built and urbanistically sensitive settlement area.

Key design elements in addressing this bottleneck are the visible tunnel portals and safety tunnels, which are to be discreetly integrated into the existing environment through architectural and design measures. The northern tunnel portal focuses on the landscape integration into the settlement area and adapts to the existing dynamically curved portal canopy as well as the existing rectangular shape of the tunnel portal.

The southern tunnel portal is located between two railway lines in an urban context. The location and design of the southern portal call for an urban, clear formal language and unity with the existing structures. Additionally, the railway bridge in front of the two tunnel entrances is to be architecturally emphasized.

Main themes:
Synergies between settlement and traffic, overlapping traffic flows, expansion of the motorway in a densely built-up settlement area, urban and landscape integration of the infrastructure corridor, bridge structures and watercourse areas, enhancement of residential areas along the motorway, design of tunnel portals and safety tunnels, noise protection, planting.

Categorisation:
Street space, Town, Main road and junction, Motorway

Project title:

Studie Engpassbeseitigung Schaffhausen N04/06 Süd–Herblingen (2011–2012)

Team:

Gruner AG (lead traffic)
Gruner + Wepf Ingenieure AG (civil engineering)
Pöyry Infra AG (civil engineering, geotechnical engineering, tunnel construction)
Atelier CORSO GmbH (design, urban planning)

Client:

Federal Roads Office ASTRA

Next project:
Landstrasse, Wettingen