Mt. Elbert Pumped Storage Trashrack Failure

Todd, Robert V.; ,

Mt. Elbert Pumped Storage Trashrack Failure

by Robert V. Todd, Bureau of Reclamation, Denver, United States,

Document Type: Proceeding Paper

Part of: Hydraulic Engineering

Abstract:

The failure of three trashrack sections for unit 2 at the suction-draft tube intake occured after one year in service. However, the trashracks for unit 1 had five years of service with no sign of fatigue damage. Both units are rated for 100 MW, but were designed and built by different contractors. Because it was not practical to dewater the intake area, the trashrack redesign was restricted to include minimal underwater work. The redesign included new features allowing longitudinal movement, but preventing vertical movement of the trashracks. Hemispherical bearings were located between the trashrack sections, and holddown fittings were located on the upper section. The middle section was instrumented with strain gages and accelerometers, and all three sections were installed. The unit was operated through its full generating range and data collected. There was minimal periodic response, but random response was significant. Histograms of random stresses were developed and the fatigue life of the trasrack was determined to be in excess of a 50-year service life.

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