Northbound bridge to carry both directions of I-5 for about four months starting mid-July
ARLINGTON – The southbound Interstate 5 Stillaguamish River Bridge has served traffic on the West Coast for more than 80 years. Now, contractor crews have begun a project to replace the aging bridge deck and some of the steel framework that supports the deck.
To keep traffic flowing during the four-month renovation, contractor crews will reconfigure the three-lane, northbound Stillaguamish River Bridge to carry traffic in both directions of I-5. Speed limits will be reduced from 70 to 55 mph in the work zone.
By mid-July, the northbound bridge will be restriped to carry four 11-foot-wide lanes, two in each direction. Work should be complete in late October.
“This is a huge project, and we’re counting on drivers to work with us to make it a success,” said Lorena Eng, Washington State Department of Transportation Northwest Region administrator. “We know that summer is the busiest travel season, but it’s the only time of year we get the warm, dry weather to do this kind of work. By shifting two lanes of southbound traffic to the northbound bridge, we can keep this vital artery open while we’re restoring it.”
The bridges see an average of about 80,000 vehicles a day, which can increase to about 100,000 a day on a busy summer weekend. Drivers should expect congestion during this project, and delays of up to 35 minutes are possible during peak hours:
• Northbound I-5: 3 to 6 p.m. Thursdays and Fridays
• Northbound I-5: 11 a.m. to 4 p.m. weekends
• Southbound I-5: 4 to 6 p.m. Sundays
Drivers can help, Eng said, by planning to travel outside the busiest hours.
“The best way to reduce congestion is to reduce the number of vehicles on the road at peak hours,” she said. “Choosing to leave a little early or a little later could help make everyone’s trip easier. Depending on your destination, a better option may be State Route 9 to the east or the Pioneer Highway between Arlington and Stanwood to the west.”
WSDOT carefully considered how bridge work might affect other nearby routes, as well as the effect other closures, such as State Route 530, might have on this section of I-5 when making the decision to renovate the southbound Stillaguamish River Bridge this summer. On May 31, WSDOT opened one lane of SR 530 for cars and trucks of all sizes to pass at reduced speed, led by a pilot vehicle. The temporary solution reduces additional traffic on I-5 and the Stillaguamish River Bridge, as work continues to fully reopen SR 530.
Preliminary work on the $8.7 million bridge project started Monday, June 9. In mid-June contractor crews will begin building crossover lanes in the median north and south of the Stillaguamish River. This will require some single-lane closures in each direction of I-5.
When the crossover lanes are complete in mid-July, crews will reduce northbound I-5 traffic to two lanes across the northbound Stillaguamish River bridge and install concrete barriers along the bridge’s center line. When the barriers are in place, southbound I-5 will be reduced to two lanes. Traffic will use the crossovers to and from the northbound bridge, and the southbound bridge will be closed.
Then crews begin the labor-intensive process of replacing the entire 607-foot-long southbound bridge deck and some of the supporting steel framework. When the new deck is complete in early fall, traffic will shift back to the southbound bridge, and I-5 will return to three lanes in each direction.
The southbound Stillaguamish River Bridge is considered “structurally deficient” because of its cracked, rutted and potholed deck. When this project is complete, the bridge will no longer be structurally deficient and should last at least another 50 years.
The bridge renovation is almost entirely paid for by federal bridge preservation funds. WSDOT is providing about $350,000 in matching funds.
The southbound Stillaguamish River Bridge opened in 1933 to carry both directions of old US 99. When I-5 was built in the 1960s, the bridge became part of the interstate.
The northbound I-5 Stillaguamish River Bridge opened in 1971, and traffic shifted to separate bridges, improving safety and traffic flow on this section of I-5.