Bell Pier Cofferdam Form for the I-205
Columbia River Bridge
Cofferdams are temporary structures used in the water to allow dewatering of the work site and permit construction to be performed in the dry. Cofferdams are used to construct a variety of structures in the water, including bridge foundations, locks, dams, pipelines, and pump stations. They are also used to facilitate repair or modification of existing structures such locks, dams and ship hulls below the waterline while the ship is still afloat. Cofferdams can be constructed of interlocking sheet piles, circular earth-filled sheet pile cells, stiffened steel plates, earth embankments, thin-walled concrete shells or a combination of these elements.
The construction, geotechnical, and structural engineers of BSCE have experience in designing cofferdams for all of the applications listed above and are familiar with the use of various types of cofferdam systems. The BSCE engineers while working with Ben C. Gerwick, Inc developed and pioneered the use of pre-cast concrete float-in cofferdams for use on the Bath-Woolwich Bridge in Maine and the New Carquinez Bridge in California. This concept was later adapted for lift-in use on two major open-sea crossings off the coast of China: the 22 km Hangzhou Bay Bridge and the 32.5 km Donghai Bridge.

Float-In Cofferdam for the Bath-Woolwich Bridge


Float-In Cofferdam for the New Rocky Reach Pump Station
BSCE's cofferdam services include:
  • Cofferdam Alternative Studies
  • Detailed Cofferdam Design
  • Feasibility Studies
  • Dewatering Analysis
  • Constructability Reviews
  • Value Engineering Studies

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