Bad Zurzach eastern bypass: easing congestion in a historic town centre
Around 8,000 cars drove through the middle of Bad Zurzach old town every day. . The new eastern bypass reduced traffic, noise and pollution in the historic town centre. Basler & Hofmann supervised the infrastructure project as overall manager and witnessed some spectacular moments on the construction site.
Kanton Aargau, Abteilung Tiefbau, Departement Bau, Verkehr und Umwelt
A cut-and-cover tunnel in creep landslide
The bypass of the historic ‘Flecken’ district made Bad Zurzach a more attractive place for local residents. Basler & Hofmann supervised the project as overall manager from 2013 through to commissioning in early June 2023. For the bypass in the eastern part of town, an approximately 1 kilometer long new dual carriageway was created. This diverts the north-south traffic from the town centre. On the Southern end, the bypass starts nears Bruggerstrasse. As the route is situated on a sidehill cut, a permanently anchored tie-back retaining wall had to be constructed over a length of just over 100 metres. The core of the project starts after the retaining wall in the shape of a 527-metre long cut-and-cover tunnel, which is also located in the creep landslide. The top-down method was chosen to construct the tunnel. Overall, 1,143 in-situ concrete bored piles are used as excavation support and as walls for the tunnel. An around one-and-a-half metre thick tunnel ceiling, prestressed transversely in parts, was built on the bored piles. The tunnel could be excavated within the ‘protection’ of the ceiling. A shared space with paths for pedestrian and cycle traffic was created on the tunnel.
New rail bridge lifted in just 54 hours
Travelling from the northern portal of the tunnel takes you to the Glocke junction with the connection to Zürcherstrasse. The junction had to be lowered due to the elevation of the route. This called for modifications to various service pipes and construction of various new retaining walls as well as the replacement of the existing SBB bridge. In a spectacular manoeuvre, the new trough bridge with a span of 17 metres was replaced while the railway line between Rekingen and Bad Zurzach was closed for 54 hours over the weekend. A 650-tonne special crane lifted the two anchors that had been prefabricated on-site. Then came the moment that drew the hordes of onlookers to the building site: the crane lifted the seemingly featherlight 210-tonne bridge deck slowly, placing it over the two anchors with centimetre accuracy. The manoeuvre was completed successfully so that at 4.30 in the morning the first train was already running over the new bridge.
Overall management and project management in the disciplines of geotechnical engineering, civil engineering, road construction, tunnel construction and service piping from project planning through to tendering and implementation including client surveying.