us army corps of engineers building strong ® ft leonard wood area office ft leonard wood area...

US Army Corps of Engineers

BUILDING STRONG®

Ft Leonard Wood Area OfficeWater Tower Lift

18 September 2015Dale Bleckman

Resident EngineerNorth Resident Office

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AgendaThe Water Tower Extension

• What happened• Options Considered• The Lift• Architect-Engineer Liability• Questions

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What Happened• 500,000 gallon water tower near vet clinic finished in

late 2014

• After completion it was determined that water pressure was about 14 psi too low.

• Research indicated that the tower was designed 33.8 feet low

• Error was due to surveyor software glitch

• Architect-Engineer accepted responsibility for the design error

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Options Considered• Use pump

Additional maintenance Additional cost

• Raise the tower 33.8 feet Use a jacking system Use cranes

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The Lift• Water Tower weighed approx 225,000 pounds

• Three cranes used (550 ton, 450 ton, 210 ton) and 150’ man lift

• 13 tractor trailers required to move one of the big cranes – over 500,000 pounds of counterweights

• New 33.8 foot, 53,000 pound section added to extend tower from 122’ to 156’

• Prep for lift started at 0530 hrs, 18 Sep 2015; tank was standing on its own by 1730 hrs same day

• Weather was one of the main controlling factor

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THE LIFT

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Architect Engineer Liability

• Design error was due to software glitch with surveyor’s program

• Designer accepted responsibility and re-designed tower

• Designer is responsible for re-construction cost but is not responsible for the additional 33.8 foot section

• Re-construction costs paid from project $s; AE Liability $s, if any, will go to US Treasury

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Questions