Deere & Ault staff (formerly with Engineering Science & Construction) was retained in early 2010 to respond to a dramatic penstock failure at the 5 MW Bear Creek Project in Northern California.
A buried portion of the 42-inch diameter penstock ruptured, as a result of external corrosion, followed immediately by negative surge pressures that collapsed an upstream portion of the penstock.
Deere & Ault staff prepared the Federal Energy Regulatory Commission (FERC) incident report, analysis of the failure mechanism and designed a repair that placed the project quickly back into power production.
In 2011 and 2012, Deere & Ault prepared the final engineering design, permitting, and required FERC engineering and pre-construction reports for replacement of buried portions of the penstock with 2,900 lineal feet of elevated penstock with working pressures up to 305 psi.
Among the many challenges on the project were active transverse slope creep, 35 inches of thermal expansion/ contraction in the penstock, and high thrust forces.
Client: Enel Italia North America