Seattle Multimodal Terminal at Colman Dock Replacement
Washington State Department of Transportation
Seattle, WA

Completed: Design complete December 2016. Construction in progress, expected completion 2023.

Size: 100,000 SF

Cost: $350 million in funding appropriated for the project

The Washington State Ferries terminal at Colman Dock is the largest ferry terminal in Washington state.


The Colman Dock replacement is a major update to Seattle’s iconic waterfront that will address the age and seismic vulnerabilities of the Washington State Ferries’ largest terminal. In 2016, this high-traffic public facility served more than 9 million people passing through on their way to and from Bainbridge Island, Bremerton, and West Seattle via King County’s Water Taxi. The replacement project will be phased over five years to enable ongoing ferry terminal operations.

As part of a collaborative GC/CM team, Wood Harbinger provided electrical power, communications, and low voltage systems design. The Colman Dock team also interfaced with the City of Seattle Seawall project to coordinate key related elements and utility services.

The new Terminal Building is designed to be constructed in two sections and will resist the design-grade earthquake at each complete phase of construction. Our design included new electrical power, electronic metering, grounding, lightning protection, communications, fire alarm, electronic security, public address, and 800 MHz ship-to-shore and emergency response radio communications.

The new Colman Dock will also support passenger-only ferry (POF) service. For this portion of the project, we provided new electrical distribution equipment served from a new Seattle City Light service transformer; a new telecommunications closet; a dedicated fire alarm system; and a one-way public address system which will enable announcements from the terminal office to the interior and exterior passenger gathering locations.

The overall site electrical systems include normal power, stand-by power, temporary and permanent communication, grounding, low voltage public address and fire alarm. We also designed electrical power and security for the vehicle transfer span (the link for vehicles to load and unload from the fixed trestle to the vehicle deck of the ferry vessel) and the overhead loading (OHL) structure at Slip 3. We designed shore power connections at each of the transfer spans to provided utility power to the vessels during tie-up in the event either the shore ramp equipment needed power or the boat. The OHL will have a flexible Gleason track enclosed duct that will protect the electrical system cables while the OHL platform is in motion.

Additional power and communications systems connections were required for the terminal auxiliary facilities including the pedestrian bridge, the bicycle entry/toll booth, the view platform, and the elevated pedestrian connector level that provides a direct connection from the entry building to the terminal building.