Kraftwerke Oberhasli AG | December 5, 2021
Since the foundation stone was laid in June, construction work on Lake Grimsel has been proceeding according to plan. The Interlaken filmmaker Christoph Frutiger captured the highlights of the third construction season in an impressive manner.
The third construction season of the replacement dam Spitallamm has been successfully completed. The construction site has been in hibernation since mid-November. Work on the construction of the new dam is expected to continue in May 2022. The highlight of the past construction season was the start of the actual concrete work. The client Kraftwerke Oberhasli AG and the construction workers of the Arge Grimsel celebrated the laying of the foundation stone for the new wall on June 23rd. Since then, the building of the century has been growing as planned.
400 concrete stages in four years
The new dam on the Grimsel is a so-called double-curved arch dam with a volume of around 215,000 cubic meters of concrete. The wall will be built in concrete stages with an average width of around 15 meters and a height of three meters. In the first phase of concreting, the main aim was to improve the processes, that is, to develop a routine, to become faster and still remain precise. The work in the high mountains is demanding, and the demands on concrete quality, material management and transport logistics are high. Around 35,000 cubic meters of concrete had been built by the end of the 2021 construction season. Around 16 percent of the wall has been built. In total, around 400 stages will be necessary for concreting the wall over a period of four years.
Key data replacement Spitallamm dam
Submission of planning application: May 2017
Start of building: June 2019
Construction time: During seven construction seasons, from May to October until 2025
Type: Double curved arch wall
Concrete volumes: 220,000 cubic meters
Costs: 125 million francs
Stauvolumen Grimselsee: 94 million cubic meters
—
The 2021 construction season in pictures
Spitallamm construction site in June 2021 before the start of the concrete work.Photos: David Birri
–
Delivery of the two construction site cranes on the winding Grimselstrasse.
–
The two construction site cranes will be assembled using a 500 tonne mobile crane and a 150 tonne mobile crane.
–
The cranes on the Grimsel are around 90 meters high and the booms up to 75 meters long.
–
Preparations for the foundation of the new dam wall in the 20 meter deep excavation.
–
The largest concrete bucket holds seven cubic meters of concrete, the same amount as a concrete mixer truck.
–
The laying of the foundation stone on June 23, 2021 with representatives of the Arge Grimsel (Frutiger AG, Implenia Schweiz AG and Ghelma AG Baubetriebe) and the client (KWO).
–
The new dam wall grows upwards in individual concrete blocks.
–
The new Spitallamm dam is being built directly in front of the old one.
–
The concrete is placed in so-called climbing formwork.
–
The new wall will also be built in two shifts during the evening and morning hours.
–
The concrete in the formwork is distributed and compacted with several excavators.
–
The wall will be built in blocks in three meter high stages.
–
Long shot of the major construction site – in the foreground the concrete plant and the two cranes, in the background the first stages of the new, double-curved arch dam.
–
– .