The Hilltop Water Tank Rafter Repair scope of work consists of: 1) remove and replace twelve (12) c-channel upper rafters; 2) repair the remaining rafters; 3) recoat all rafters, interior roof, and appurtenances with three (3) coats of epoxy; 4) inspect and patch the interior coating as needed; 5) install a new cathodic protection system to prevent corrosion; 6) install new seismic valve actuator; 7) install new target and float; 8) reuse/replace seismic cross bracings; 9) replace 200 steel fasteners; 10) replace all gaskets; and 11) lower the overflow three (3) feet for seismic mitigation. The expected completion date is 120 consecutive calendar days after receipt of the Notice to Proceed. If you discover any error or omission in the plans, specifications, or proposal, or have
any question concerning the bidding documents, please contact:
Ramona Mejia, Assistant Engineer
Ventura County Waterworks District No. 8
Department of Public Works
2929 Tapo Canyon Road
Simi Valley, CA 93063
Telephone (805) 583-6795 The 1 MG Hilltop Water Storage Tank is a welded steel above ground cylindrical tank.
The tank is approximately 85 feet in diameter by 24' high, providing a nominal capacity
of 1 million gallons. It is the only tank on site.
The tank shell has three (3) courses connected to a pitched roof. The roof plates are
supported internally by a structure consisting of a column, a ring girder, and beam
rafters. The beams rest on welded shell clips, the girder, and a center dollar plate. The
tank has one (1) center roof vent and one round shell manway. There is one (1) interior
and one (1) exterior ladder, each leading to a roof access hatch. The roof has multiple
roof hatches. The tank rests on grade within a grand band, which sits within a paved
site. The tank does not have any anchoring. The overflow has a funnel and screened
air-gap. There is an internal cathodic protection system associated with this tank.
The tank was recoated in 2014, but there is advanced corrosion in the form of dark rust
and scaling (CSI Corrosion Grades 2 and 4) on the lower and upper flanges (lips) of the
rafters and girders. Further, although many of the roof support structure fasteners are
free of any corrosion, there are some locations where the fasteners were found to have
dark corrosion (CSI Grade 2). The total amount of corrosion on the roof was rated to be
approximately 0.1 percent of the total roof surface. Questions about the proposed project will be accepted no later than May 30, 2023 at 5:00 pm.
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