Monitoring Mass Concrete at Hydro Station
Switzerland: Imagine the energy carried by the water rushing 1833 meters downward to the three massive turbines at Bieudron power plant. A ring pipe at each turbine directs the water into five jet nozzles where it exits at a velocity of 690 km/h and hits each of the turbine buckets 35 times per second with a force of 57t per jet.
When the turbines were installed in the underground powerhouse in 1996, Geotrade SA was asked to place vibrating wire embedment strain gauges in the mass concrete surrounding the ring pipes. The embedment strain gauges were used during testing to verify that the design performed as expected.
The complete system was brought on line in May, 1998, doubling the capacity of the Grande Dixence power scheme. The Bieudron power house sets a record for the maximum net head (1844m) and the size of the turbines (three 423 MW Pelton turbines, each powering a 465 MVA generators. The total excavation volume was 7 million cubic meters for the galleries and the underground powerhouse.