Infra Tunnel relies on the alkus^® formwork panel for the "H10 - Tunnel de La Clusette" project

 

The alkus^® formwork panel made of solid plastic was used in the construction of the safety tunnel for the “Tunnel de La Clusette” in the Swiss canton of Neuchâtel. The construction company Infra Tunnel SA used the alkus^® GM6 on the tunnel carriage from Rubrika and partly also in the tunnel formwork from PERI. With success: the alkus^® provided the required flexibility and delivered the perfect finish. 

After 50 years of operation, the one-kilometre-long “Tunnel de La Clusette” no longer meets the required safety standards. As part of the "H10 - Tunnel de La Clusette" project, it will therefore be renovated from 2021. In addition, a safety tunnel will be built parallel to the road tunnel so that it can be evacuated in the event of a fire. The project is scheduled for completion in 2026. The client is the "République et canton de Neuchâtel". The contract to build the safety tunnel, including the connecting tunnels to the main tunnel, was awarded to Infra Tunnel, a Swiss construction company specializing in underground construction work. 

The right formwork for high requirements

A perfect concrete finish was required, therefore the choice of formwork facing played an important role in the project. In addition, a formwork panel had to be selected for the curved special formwork that would adapt to the shapes without any problems. The project managers therefore decided to use the glass fiber-reinforced solid plastic panel alkus^® GM6 for the formwork work on the safety tunnel and, in part, on the connecting tunnels. The six-millimetre-thick formwork panel supplied by alkus AG from Liechtenstein is flexible, yet at the same time rigid and easily meets the high standards of surface quality. In addition, thanks to its robustness and durability, it eliminates the need to replace the formwork facing, which is particularly time-consuming in tunnels.  

Rubrika formwork carriage riveted directly to the alkus^® panel on site

The alkus^® GM6 with the tunnel carriage from Rubrika was used to build the safety tunnel. "Rubrika has been a satisfied alkus customer for years and was therefore already familiar with our products and their advantages and application," explains Michael Tschenett, Managing Director of alkus AG. The Rubrika formwork carriage was riveted directly on site with the alkus^® GM6 and not welded but joined directly. Those responsible also riveted the panels in a tight grid to prevent concrete from flowing in - which in turn would have impaired the desired surface result.  

Matt formwork panels for the perfect finish

PERI tunnel formwork was used for the connecting tunnels of the main and safety tunnels as well as the parking bays and - on the initiative of the client and Infra Tunnel - the alkus^® GM6 formwork panel made of solid plastic was also used in some areas. A team from alkus AG supported PERI Switzerland at the site in Ohringen near Winterthur with the formwork: “We attached the alkus^® to the PERI plywood formwork carriage, welded it and then matted it in order to achieve the required perfect finish for the concrete,” explains Michael Tschenett.

alkus^® delivers with perfect results 

The results are impressive: By covering the special formwork with the alkus^® GM6 formwork panel, the desired results could be achieved in all cases without changing the formwork facing. “We are very satisfied with the feasibility of the GM6 panel and also with the excellent results,” says Fabian Epiney, Head of Special Formwork Construction at PERI Switzerland

Press release