Fear of cracks

The S-Link as an acid test for Salzburg’s old town

An expert commissioned by 22 homeowners around Lederergasse has warned of damage to the historic houses in Salzburg's old town.

(Bild: Tschepp Markus)

The fact that two tunnels are being dug under historic buildings in Salzburg's old town for the planned extension of the Salzburg local railroad - known as the S-Link - has put building owners on alert. An expert commissioned by them warns of cracks. The Monuments Office relies on strict conditions. 

"The planned construction of the S-Link endangers the existence of the historic old town; at the very least, considerable, irreparable damage to the building fabric is inevitable," explains Wolfgang Zipperer, civil engineer for civil engineering, in his expert opinion. He was commissioned to do this by 22 house owners in the right-hand side of the old town.

Excavations in the notorious Salzburg lake clay
Although the final route of the partly underground local railroad extension has not yet been determined to the exact meter, current plans call for two tunnel tubes to be dug under the buildings in the Lederergasse area at a depth of around 15 meters in the notorious Salzburg Seeton. Some of the houses affected are 800 years old, have no cellars and no foundations. The streetcar ceilings lie loosely on the walls.

"Even with modern construction methods, these historic buildings cannot be made safe. The tunnel tubes will cause subsidence, which will inevitably lead to damage," warns Zipperer. Even safety measures would endanger the houses.

The S-Link company is reassuring: the subsoil has been thoroughly explored. The risk of subsidence and ground deformation is minimized.

(Bild: S-LINK)

S-Link company relies on state-of-the-art technology
The S-Link company naturally sees things differently and points to state-of-the-art technology. So far, 103 pressure soundings and 81 test drillings have been carried out from Mirabellplatz to Salzburg-Süd. The subsoil explorations are currently being completed. The submission plans for the second, affected section are expected to start at the beginning of next year. 200 specialist planners are at work on the S-Link.

"The top priority is to minimize subsidence and ground deformation and to ensure the stability and safety of the existing buildings," explains S-Link specialist planner Manfred Eder. The project company refers to the upcoming environmental impact assessment procedure, which will also take into account the protection of historical monuments.

The old town houses must be preserved and I assume that the S-Link company is planning in such a way that the risk is minimized or no longer exists.

Landeskonservatorin Eva Hody

Bild: Gerhard Schiel/GERHARD SCHIEL

Strict conditions to protect the old town
State Conservator Eva Hody relies on particularly strict requirements to protect the old town. "From as-built surveys and documentation to structural safety - everything has to be agreed with the heritage authority. The old town houses must be preserved and I assume that the S-Link company is planning in such a way that the risk is minimized or no longer exists," says Hody. 

If historic houses are actually at risk, the company will have to react. This does not reassure local residents. They are calling for a geological and geotechnical feasibility study, including a risk analysis.