Leister Process Technologies interviewed Urs Streuli of Sika Bau AG, regarding the New Rail Alpine Crossing (NEAT) construction in the Gotthard Tunnel. For more from the project, see Christophe von Arx and Norbert Tholl’s article “At High Speed through the Heart of Europe: The Gotthard Base Tunnel.”
The NEAT construction site is dominated by difficult climatic conditions. What does this mean for the machinery and equipment used?
Temperatures of up to 82°F and an air humidity of over 90 percent predominate in the tunnel. A clean weld seam preparation is therefore essential. It is also important to store all machinery cleanly after use in order to prevent unnecessary corrosion.
What are the most important measures for complying with the processing quality?
Clean work in general, as well as clean weld seam preparation. What is more, the welding must not be too fast and must never be performed in water.
How do you monitor the processing quality?
Every weld seam is subject to a visual inspection with the screwdriver; dual seams with a test channel are “inflated.” Peel tensile tests are also carried out regularly. The latter, either in the Sika laboratory or by Tecnotest AG. A control weld is also conducted when starting work.
What are the most important advantages of Leister devices from your point of view?
We work exclusively with Leister devices and depend on their reliability. They correspond exactly to our requirements. We have been working with Leister equipment for as long as I can remember…
Sometimes the spaces are very confined on a tunnel construction site like the one here with NEAT. How effective does the Leister machinery prove to be?
TRIAC Drive and TWINNY S are practical and lightweight welding machines. That makes them ideally suited for use even in very confined spaces like here. Even overhead welding work does not pose any problems.
Are you happy with the support provided by the Leister Sales and Service Center?
Yes, we are satisfied with the service of the Leister partner responsible. If one of the devices needs a service, it is soon ready for use again afterwards.
Does Sika Bau AG also work with Leister equipment for other major projects? If yes, which ones?
We only work in Switzerland. Sika Bau AG uses Leister devices exclusively in all tunnel projects here, for example on the bypass tunnels in Zurich, Lungern and Olten, and in the Ceneri base tunnel (part of the new flat rail route through the Alps).
Download a PDF copy of the Gotthard Tunnel article and interview with Urs Streuli here
Lesiter Process Technologies: www.leister.com
