Interviev project A9 2021: cut and cover tunnel Raron

Highway A9

cut and cover tunnel Raron – A project of the century in the south-westernmost canton of Switzerland (Valais)

Project facts:
Construction time: 74 months
Bored pile wall concrete: 63’500 m3
Excavation pit (solid, incl. bored piles): 450’000 m3
Reinforcement (incl. bored piles): 20’000 t
Concrete (excl. bored piles): 106’000 m3
Formwork: 107’000 m2
A total of 2‘844 piles, of which 2‘240 were a secant pile wall Ø 1300 mm

Facts special civil engineering piles:
5‘900 t steel, 76‘000 m3 concrete
2‘240 pcs. secant pile wall Ø 1300 mm
total of 2‘844 piles:
2‘240 pcs. Ø 1300 mm
294 pcs. Ø 1000 mm
170 pcs. Ø 880 mm
140 pcs. Ø 750 mm
Total pile lengths 61 km
Execution of pile production; Ghelma AG
Connecting reinforcements 26 Stück each Ø 30 mm x 1.5 m
Pile breaking with Brextor; Theler AG
Excavator Komatsu PC290

A project that not only connects the whole of Valais, but also brings added value to the population, trade and tourism.

31,8 km of motorway for the Upper Valais! As part of the completion of the Swiss motorway network, the canton of Valais is building the remaining section of the A9 highway in Upper Valais between Sierre and Brig. The project is being managed by the Service for National Roads Construction (DNSB) based in Brig-Glis (Gamsen). The Federal Roads Office (FEDRO) is responsible for supervising the construction of the A9 highway.


The project is explained in more detail here in an interview with Egon Studer (Department of Mobility, regioanl development and Environment (DRMU), Service for National Roads construction (DNSB)), who is managing and supervising the construction site in both structural and technical matters.

Mr Studer, what were the construction challenges of the project?

The Raron cut and cover tunnel (GERA) is located south of the Rhone in the Turtig district of the village of Raron. The double-track SBB railway line runs parallel to this to the north of the project, at varying distances. The smallest distance between the centre line of the secant pile wall and the centre line of the southern track is around 4.30m. Furthermore, on the south side, the structure is close to the buildings of the internationally active company Jabil, whose production facilities are sensitive to vibrations. For this reason, all necessary construction work is geared towards minimising deformations and vibrations. The excavation pit end is one of the key components in terms of risk (defects in the pile wall). An essential part of the safety concept for the excavation pit is its comprehensive monitoring and the neighbouring area. The purpose of monitoring is to recognise hazards at an early stage and to ensure that measures are taken to prevent damage.

Can you tell us how planning has changed as a result of using Brextor?

Thanks to the efficient working method and workflow achieved by using Brextor, follow-up work is easier to plan. The work output per day is quickly calculated. This means that follow-up work can be planned quickly and precisely.

How would the project have gone without Brextor?

As the client, we are convinced that with a conventional method of pile breaking, the planning for subsequent work and, above all, the quality of the pile head would not have been as optimal.

As a client representative, where do you see the greatest added value of Brextor?

  • Performance per day
  • Precise
  • Flexible
  • High quality (level concrete pile head, no cracks, no damaged reinforcement, etc.)

How do you rate the quality of Brextor compared to previous processing methods?

The rotating chisels always create a horizontal surface. No vertical forces act on the pile head.

“Uncontrolled spalling and cracks in the pile head area can be prevented with the system.”

Work can also be carried out with centimetre precision. Apart from cleaning, no further work steps are required.

How much time and how many resources can you save by using Brextor?

We can only judge how much time is saved compared to the pre-tests. Here we can assume savings of around 50-70 per cent.

Do you also see advantages in working with Brextor in the current situation with COVID19?

In my opinion, there are advantages to the work process. On our construction site, this work is carried out by two employees. One is the machine operator in the excavator and the other one is a construction worker. They have no physical or close contact during the work process.

In your opinion, what are the special features that distinguish Brextor from traditional pile breaking methods?

“In particular, the care and precision with which the pile breaking – or lets say milling – to the height is a speciality of Brextor. In addition, the work can be planned, which is extremely important for follow-up work.”

Made in Switzerland, how important is this label to you?

Switzerland is known for its high standards. With the product, this segment can be taken into account. In this way, we not only maintain quality, but also secure innovation and jobs.

How do you personally see Brextor’s chances of international success?

Personally, we see huge potential for international success with Brextor.

“Brextor stands out from conventional pile breaking methods thanks to its performance and quality.”

The demand for expected and maintained quality alone should speak in favour of international success.

Will you be using Brextor again for future projects?

Yes, we will include this reference to Brextor in the tender text.

Will you recommend Brextor to others?

Yes, definitely. Based on our experience, we can recommend the product at any time.

Thank you Mr Egon Studer for your openness and for answering our questions.

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