October 2, 2020

New pedestrian bridge opens in Everett

Photo by Adam Hunter/LMN Architects [enlarge]

The 75-foot-tall concrete and steel bridge carries major utilities.

The 257-foot-long Grand Avenue Park Bridge opened Aug. 26 in Everett, creating a sequence of new civic spaces and connecting the park with the city's growing waterfront district.

LMN Architects said it is the first pedestrian and utility bridge it designed in partnership with KPFF Consulting Engineers.

The asymmetrical weathering steel truss spans from a hillside to a vertical concrete tower. In a press release, the architect said the 75-foot-tall concrete and steel bridge solves a complicated sequence of grade-changes and utility needs in an unlikely new form that weaves pedestrian ramps and stairs above, around, and inside a sloping truss, presenting an inviting new crossing from the park to the district.

The bridge carries major utilities while navigating a network of existing electrical lines, a five-lane highway and the BNSF train tracks at the base of an 80-foot-tall steep slope, preserving views from the park above. In part, the views are kept by having a unique entrance onto the top of the bridge such that most of the bridge structure is below Grand Avenue Park, the architect said.

LMN said the bridge's paths, stairs and spaces create a variety of views beyond and within that make it a place of discovery.

The truss form recalls traditional railroad trusses found in the Pacific Northwest. LMN said the structural elements are constructed of weathering steel, a raw form of steel, which uses rust to form a protective layer, providing corrosion resistance and enhancing the bridge's maintainability over time. Wrapping around and running through the truss, a shining, lacey guardrail also serves as the bridge's de-facto wayfinding system, contrasting with the raw character of the rusted truss.

The guardrail features a perforation inspired by the forms of the surrounding natural environment. LMN said the varied density of perforations was designed to enhance reflectivity of the artificial lighting, improving the performance of the integrated linear lights at the top of the rail while minimizing glare and light pollution.

Each aluminum panel is unique, responding to the geometry of the bridge, views beyond and varying guardrail requirements, the architect said.

The overlay of large-scale truss elements and small-scale perforations creates a dynamic experience of view, light and shadow along the walking path. A tall concrete elevator and utility core serve as the western abutment, its concrete walls blasted with the same perforation pattern and wrapped in a staircase that leads to the pedestrian-level waterfront promenade.

The total project cost was roughly $20 million, according to the city of Everett.

(Editor's note: This story has been changed to include the total project cost from the city of Everett.)

KPFF was the prime consultant and structural, civil and plumbing engineer.

The team also included Interwest Construction (general contractor); McMillen Jacobs Associates (civil engineer); Tres West Engineers (mechanical engineer); Stantec (electrical engineer); The Greenbusch Group (vertical transportation); Landau Associates (environmental engineer); Ott Consultants (constructability review and construction scheduling); KBA (construction management); Everett Parks & Recreation (landscape); Horton Lees Brogden Lighting Design; and HWA GeoSciences and Landau Associates (both geotechnical).

The project follows a decade of planning and coordination between the city, Port of Everett, BNSF Railway, Snohomish County Public Utility District, Washington State Department of Transportation and Everett's Northwest neighborhood.