Sango Brook Cofferdam and Trestle, Sango Brook, Labrador


HEC provided the full design for a multi-cell deep cofferdam in very difficult soil and water conditions to allow the contractor to install a water pipe to service the local community which had been without clean water.

The project had been previously abandoned by another contractor due to the difficult conditions including very unstable soils with almost no shear strength (Ka=1.0) creating very large soil pressures on the cofferdam structure. HEC completed a full design of a modular cofferdam to allow the contractor to install the pipe from a pumping station down to the water, design modification of a permanent steel sheet pile intake structure using the materials from the temporary cofferdam and the design of a temporary construction trestle to allow the contractor to complete the installation of the intake structure.

Client: Waterworks Construction Limited

Value: $7 M (Total Project Cost)

Year: 2009

Role: Detailed Engineering design of temporary cofferdam and trestle. Value Engineering of the Headwall of the permanent intake structure