Blair Waterway Horizontal Directional Drilling
Location: Seattle, Washington
Owner: Port of Tacoma
Market: Power/Utilities
Construction Cost: $3.2 Million (Approximate)
Construction Start/End: 2004/2005
Jacobs Associates’ Role: Trenchless Engineering
As part of infrastructure improvements to accommodate the next generation of shipping container vessels, the Port of Tacoma developed plans to widen and deepen the Blair Waterway shipping channel, situated within the Port's Industrial Development District. First though, the Port had to relocate several conflicting utility lines running under the waterway—fiber optic and copper cable communication lines and a water main—as well as high voltage transmission power lines running overhead. All of these utility lines ultimately needed to lie underground beyond the limits of the future channel.
During preliminary design, Jacobs Associates evaluated several methods of construction, including horizontal directional drilling (HDD), microtunneling, and conventional tunneling methods. This work included establishing constructability requirements, evaluating construction staging areas, developing preliminary alignments and profiles, evaluating construction risks, and performing preliminary cost estimates. In the end HDD proved the preferred method used to relocate the utility lines, approximately 2,100 feet long each.
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