Experience in using string systems as horizontal displacement meters during observations of deformations of hydraulic structures at the Sayano-Shushenskoe hydroelectric station

1. The systems of elongated triangles located at elevations 413, 467, and 344 m do not give reliable results, as a consequence of which they cannot be used as horizontal displacement meters. 2. The displacements of the ends of the adits recorded from the NET readings are a consequence of measurement errors. 3. The use of string systems as horizontal displacement meters of hydraulic structures can be used only with their complete protection from airflows, which is practically impossible to do. 4. The use of 3-m invar bars, used as meters of the small sides of the NET, for determining deformations of concrete and bank adits is possible.