PENTAGON HEATING AND REFRIGERATION PLANT REPAIRS
Client: Washington Headquarter Services
Project Start: April 2015
Project Completion: August 2015
Marine Technologies, Inc. Key Personnel:
Project Manager: Luke Browning
Project Superintendent: Dave Capino
Owner's Representative: Helina Germoson
The New Intake Structure consists of a rake house which is split into two separate trash racks between the east and west side. They are designed as the primary defense against large obstructions and foreign objects entering the intake system. The east side trash screen is missing entirely. MTI furnished, fabricated and installed a temporary screen in this location until the permanent replacement could be procured and installed for both the racks. Due to the extremely large size of the rakes, MTI required the use of a Grove Crane for removal and installation of the rakes through the existing roof-top access. The existing fiberglass, angles and bracing was replaced in kind with matching steel products to provide extra strength and stainless steel hardware was used to prevent corrosion. All steel angle bracing and new rakes received a marine coating to withstand the corrosive nature of the brackish water.
Debris was removed from the two slurry chambers of the Intake System. The slurry pits are 60' in depth and designed so the base of the shafts are 3' below the invert of the intake pipe to collect loose material. The debris filled the shafts so it was flush with the invert of the pipe and not functional. Large debris materials required the use of a small crane to lift it to the surface. Remaining smaller organic debris was loaded into 50 gallon barrels and pulled to the surface by the crane. The slurry and silt left over was pumped into a Geotextile fabric bag at the surface and sediment was separated from the water which allowed the clean water to return to the source. All sediment and debris was removed from the site and disposed of in an approved manner. Because the depth exceeded 50', the divers could not be on the bottom for more than one hour without decompression. MTI rotated divers frequently utilizing a large 16-man dive crew, and also provided a decompression chamber in case of emergency.
The motor, reducer and clutch were all replaced in Traveling Screen #3. All replacement equipment was supplied from the original equipment manufacturer (OEM), and installation was either supervised or completed by OEM technicians to ensure product compatibility for a fully functional traveling screen.
Repairs were made to concrete spalls located inside concrete structures identified within the Condenser Water System. The identified spalls were repaired by MTI divers using a two-part epoxy called Splash Zone. The divers cleaned the spall and surrounding area using a grinding wheel or wire brush, hand mixed the two-part epoxy and applied it to the surface area of the concrete structure. This product can be applied, troweled out by hand and smoothed in a submerged setting.