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November 23, 2020

Report: replacing Ballard Bridge could cost $1.5B, take 12 years

By BENJAMIN MINNICK
Journal Construction Editor

SDOT photo/flickr [enlarge]
Ballard Bridge is a 103-year-old double-leaf bascule bridge.

A report finished earlier this month by the Seattle Department of Transportation shows replacing the century-old Ballard Bridge could cost as much as $1.46 billion and take up to 12 years to plan, design and build.

The Ballard-Interbay Regional Transportation System study focuses on replacing or rehabilitating Ballard Bridge, as well as replacement options for Magnolia Bridge. The final report was given to the state Legislature, which last year earmarked $700,000 for the study. It also looks at future transportation improvements between Ballard and Interbay that involve bicycle and pedestrian facilities and keeping buses and freight moving.

SDOT said the report is a first step toward identifying transportation funding opportunities with the Legislature, and in the coming years the agency will develop a strategic management plan and proceed with the preferred alternatives for each bridge. To date, no funding has been identified for design or engineering of the bridges, much less construction.

Three options were originally considered for Ballard Bridge: a fixed span soaring 150 feet over the Lake Washington Ship Canal; a mid-level span that is movable for tall ships; and a low-level span similar to the existing double-leaf bascule bridge. SDOT dropped the high-level span after concerns were raised about multimodal connections at the north end of the bridge, its overall length of 6,435 feet, and a lack of intermediate exits for walkers and cyclists.

The 5,335-foot-long mid-level option would be 65 feet above the waterway with redesigned access on both ends. It would open on fewer occasions than the existing bridge due to its higher clearance. Its estimated overall cost is $680 million-$1.46 billion, with construction at $655 million.

The low-level replacement would have improved access on the south end for all modes of traffic. It would be a 3,035-foot-long lift bridge with a similar clearance, 44 feet, as the existing span. Its estimated overall cost is $330 million-$710 million, with construction at $298 million.

Both replacement options would take eight to 12 years to complete, including three to six years of construction. No specific schedules have been set because no funding has been identified to advance the design phase.

Two options for Magnolia Bridge include an in-kind replacement and a new alignment along Armory Way. The overall cost of the one-to-one replacement is estimated at $340 million-$420 million, while the Armory Way option is $200 million-$350 million. The report noted that the Armory Way option would increase travel times by an average of 12.7 minutes.

The Magnolia Bridge replacement options also would take eight to 12 years to complete.

The Seattle City Council and mayor will ultimately decide which alternatives to advance for the Ballard and Magnolia bridges. The report says the cost for either project “will far exceed the city's financial means without outside funding.”

Ballard Bridge's condition is rated as “fair.” It was built in 1917 and rebuilt in 1937. It's 2,854 feet long and connects Ballard to Magnolia, Queen Anne and downtown via Interbay. About 59,000 vehicles used it daily before the pandemic throttled traffic volumes.

SDOT says it performs regular maintenance and frequent inspections to ensure the bridge is operational and safe for both road and marine traffic.

“Due to the age of the structure, more significant rehabilitation may be needed to sustain its current level of operation,” the report says. “Since the structure is still in good condition today, we have an opportunity to plan ahead and look beyond just maintaining its current form and function.”

The 1930 Magnolia Bridge is one of five city bridges rated in “poor” condition, according to SDOT. It carried about 20,000 vehicles a day before the pandemic. It's a 3,600-foot-long truss bridge that was built in 1930. Parts of it were rebuilt following damage from a 1997 landslide and the 2001 Nisqually earthquake. It spans the BNSF Railway tracks and filled tidelands of Smith Cove to connect Magnolia and Interbay.


 


Benjamin Minnick can be reached by email or by phone at (206) 622-8272.




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