Road bypass Weyer – Tunnelling in loose soil beneath existing buildings

The small town of Weyer is located in Upper Austria on the B121 Weyerer Straße. The B121 leads through the historic market square of Weyer, which is characterised by confusing bottlenecks that can only be passed in one lane. For decades, these bottlenecks have caused congestion, mainly due to heavy traffic. For residents, the burden of air pollution and noise is high. The roads department of the Upper Austrian Government has been planning the construction of a bypass for many years. Construction finally started in the summer of 2022. The Weyer bypass construction lot is 1.2 km long and includes the construction of two NATM tunnels, a vertical escape shaft, a bridge over the river Dürnbach, two roundabouts, and one traffic junction. The tunnel construction works are carried out in urban areas, in loose material with little overburden and partly under existing buildings. These boundary conditions make the project a challenge for all involved at every stage.