Project Location: Washington, DC
Contract Amount: $24,500,000
This project involved the construction of a new finished water pumping station with twelve new pumping units. The structure included a lower level area, pump room, operations room, electrical room, battery room, generator room, and toilet rooms.
The project also included the construction of a new electrical substation and new underground feeder ductbanks. The substation included new diesel storage tanks.
Major work items included:
• Sheeting and shoring
• Underground utilities
• Cast-in-place structural concrete
• Structural steel and miscellaneous metals
• Synthetic slate roofing
• Process mechanical
• Maintenance of traffic
• Dewatering system
• Site demolition (removal of concrete and structures)
• Temporary support of excavation (driven cantilevered soldier piles and hardwood lagging
Mechanical work included:
• Horizontal split case centrifugal pumping units
• Fuel storage tank removal
• Fuel storage tank and accessories
• Meters and instrumentation
• Venturi Meters
• Control panels and enclosures
• PLC input/output subsystem
• Bridge cranes
• High performance butterfuly valves; crane valves; surge relief valves; pressure reducing valves
• Underground yard piping, individual tie-ins and chlorinator (24" and 30")Temporary line stops
Sequence of Construction and Outage Limitations:
The work on this project was scheduled and proceeded in such a sequence as to avoid interference and delays to normal DC WASA operations.
In order to keep to a minimum any interference with proper operation of the existing facilities, disconnections and reconnections were made only at such times and in such a manner as approved by the Engineer in writing. At times, we operated on a 24-hour per day basis.
We submitted an overall shutdown schedule. This schedule included a summary description, shutdown time and date and a time scheduled sequence of tasks, including identification of critical stages in the project where a decision to abort the operation would be made if satisfactory progress were not being made or unforeseen conditions would likely result in excessive out-of-service duration.
At least five (5) days prior to the interruption of service, we submitted a shutdown request.
In addition to other scheduling and sequencing needs, we met the following phasing requirements:
A. Complete work in and round Minnesota Avenue, SE at the following locations prior to a particular date:
• Linestop installation on Low Service Main at Minnesota Avenue and 18th Street
• Installation of 30" by 24" tee on Low Service Main (Location "A") and new Low Service/Suction Interconnection Main across Minnesota Avenue
• In-Line thrust block on Anacostia First High Service Main in Minnesota Avenue
• Installation of 24" by 24" tee on Low Service/Suction North ("Location B") and new Low Service/Suction North Main along R Street.
B. Complete interconnections at the following locations after a particular date.
• Low Service and Anacostia First High Service Connections at Location "C", Location "E" and Location "G".
We provided a flushing connections and circulation through any "dead end" resulting from the required sequencing. Circulation rate needed to be adequate to replace the volume in water in each section once every 24 hours and was maintained as a continuous flow.