The Quail Creek Crossing BFV vaults, near Denver, Colorado, experienced two hydro test pressure failures. In 2005, GES Tech Group was tasked with determining the root cause and specifying a modified design. The basic design defects were identified and an extensive repair was specified and implemented in cooperation with the contractor. Installation of modified restraints was supervised by GES Tech Group and the final approved hydrotest was performed and documented under the supervision of L. J. Mott, PE. Final documentation included anticipated dial gauge readings due to axial loading of properly designed control rods.
Damage to the couplings and the 90 degree elbow nearby following the original hydrotest that revealed the design defect. Root Cause was a lack of adequate restraint for hydrostatic forces and misplaced restraint load paths.
(Photo credits: Hamon Infrastructure, Inc.)
