• Project

SR 411 Cowlitz River Bridge – Replace Bridge Deck

Project overview

Beginning in early 2023, contractor crews will install safety improvements and work to extend the useful life of the almost 60-year old bridge. The concrete bridge deck will be replaced and widened, to allow for a new, wider sidewalk on the north side of the bridge, new pedestrian and bicycle-friendly traffic barriers, and a new waterline.

Feb. 2023 - Jan. 2024
Project status

What to expect

Beginning Monday, Feb. 20, contractor crews will start work to replace the existing SR 411 Cowlitz River Bridge deck. 

Once bridge deck replacement work begins, travelers can expect year-long intermittent, alternating single lane closures as well as occasional full bridge closures. Most closures will take place during the daytime hours, however, some nighttime and weekend closures will be needed. Nighttime closures are tentatively scheduled to occur between the hours of 10 p.m. to 7 a.m. 

To keep travelers moving, crews will install a temporary traffic signal on either side of the bridge that will operate similar to a stop light, alternating vehicles one at a time through the construction zone. Once activated, the temporary traffic signal will operate around-the clock throughout the duration of the project. Flaggers will periodically provide traffic control through the area as needed through various phases of construction. Delays of between 15-20 minutes are expected throughout the duration of construction.

During the full bridge closures, travelers will be encouraged to take alternate routes to gain access across to and from the City of Castle Rock and surrounding areas. Travelers along northbound SR 411 can continue on to use SR 506 to I-5, and travelers along southbound SR 411 can continue on to use Lexington Bridge Drive to I-5. Travelers will be notified seven days in advance of each full closure through travel advisories, news updates, and reader boards posted near the project area.

Full bridge closures will be needed during concrete pouring to allow time for the concrete to set and cure before drivers can travel across the new bridge deck surface. When possible, crews will schedule work overnight to reduce traffic impacts.

Travelers living or working nearby the construction area should expect construction noise and some slight disruptions to the way they travel through the area. WSDOT is working with the school district to reduce and minimize delays during peak school travel times. 

Beginning in Feb. 2023, the existing bridge deck along the SR 411 - Cowlitz River Bridge, in Castle Rock, WA, will be removed in stages and replaced with a new, widened bridge deck that meets current bridge standards for safety and accommodates all modes of travel.