Fabrication of cofferdam template for lock system

  • Customer: U.S. Army Corp of Engineers (subcontracted by Durocher Marine, a Division of Kokosing Construction Company, Inc.)

  • Location: Sault Sainte Marie, Michigan

  • Duration: September 2009 – October 2009

  • Material: Steel

Moran Iron Works fabricated a template for a set of cofferdams. By definition, a cofferdam, sometimes called a coffer, is a temporary enclosure built in water that allows for an area to be pumped out, forming a dry environment for work to be performed. They are typically welded steel structures with cross bracing enclosed in sheet piling.

These cofferdams were built for the Soo Lock Complex, Sault Sainte Marie, Michigan, U.S. Army Corps of Engineers Detroit District. They were used to dewater the locks and allow maintenance and repairs to be performed during the annual lock closure.

“We picked the assembled template, set on floats, secured in position, set all 12 legs, removed floats, lowered to working level and installed most of the leg bolts.  Everything performed better than could reasonably be expected.  All of the Durocher and Moran dimensions match our intent within a fraction of an inch.  Actual center of template is within 0.1” of Corps design center so they had the lock walls located rather accurately too.

Circumference was measured within 0.25″ of theoretical from the Moran shop drawing.  This is in over 271 feet!  We probably had incorrect tension in the tape.

Thanks again for your creativity in the design phase and the excellent workmanship.”

– Stan Neff, P.E., Operations Manager, Durocher Marine, a Division of Kokosing Construction Company, Inc.