After the Seikan Tunnel in Japan and the Channel Tunnel between France and Great Britain, the 35 km long passage through the Lötschberg Mountain is the third-longest tunnel in the world. 20% of the excavation work was carried out using tunnel boring machines and 80% was blasted resulting in nearly 16 million tonnes of rock being removed. From the fi rst blasting to initial rail tunnel operations, only an eight-year construction period was available to the contractors.
Rentable standard components formed the basis for the formwork carriage construction, providing efficient construction sequences for both operating centres at the Mitholz base. The tunnel formwork carriage was moved on rails using chain hoist equipment and served fi rst to form the arched side walls and included brackets required for the subsequent fitting of crane tracks on the side as well as the crown bar. Concreting forces were safely transferred via the load-bearing system sub-structure. Two hydraulic cylinders on each side allowed simple and fast striking of the foldable fi ller element for the crown bar.
Concreting the calotte took place in a second stage i.e. the arched slabs. After disassembling the side formwork, the formwork carriage was retracted into the starting position and the calotte formwork for the arched slabs could then be installed on the carriage. Lifting and lowering the formwork carriage was comfortably carried out by four hydraulic drive components which had already served as height adjustment units for the arched side walls.
Albin Matschek
Supervisor
“The flexible and customised PERI modular construction system with pre-mounted units easily fulfilled all requirements.”
