State officials intend to complete several projects on Interstate 5 in the Vancouver area next year before the Interstate 5 Bridge’s northbound span shuts down for trunnion replacement.
The Washington State Department of Transportation has scheduled an open house for 4 to 7 p.m. Wednesday at Vancouver Community Library, 901 C St. People can stop by anytime during the event to learn about four projects.
• Trunnion replacement: The I-5 Bridge’s northbound span will close for up to nine days, from Sept. 12-20, so crews can replace parts on the lifting mechanism that allows taller vessels to pass under the drawbridge.
The mechanism includes sheaves, or wheels, cables and trunnions, which are axles, 20 inches in diameter, that help turn the sheaves and lift and lower the span.
In 1999, a crack was discovered in a trunnion on the northbound span’s south tower, two years after the span was shut down for six days in September 1997 to replace a trunnion on the north tower.
The project in September will replace the cracked trunnion and other components used to lift and lower the bridge.
During the closure, drivers, cyclists and pedestrians will be shifted to the southbound span. A movable concrete barrier will provide two lanes for southbound traffic during the morning commute. Crews will move the barrier midday to allow two lanes for northbound traffic for the evening commute and move it again before the morning commute.
Four freeway ramps will be closed during the work:
• The offramp from I-5 northbound to state Highway 14.
• The onramp to I-5 southbound from Highway 14 and Washington Street.
• The onramp to I-5 northbound on Hayden Island in Portland.
• The onramp to I-5 northbound from Marine Drive in Portland.
Heavy congestion is expected on the Interstate 205 Bridge, Interstate 84 in Portland and on city streets near the I-5 Bridge on both sides of the Columbia River. If drivers do not alter their behavior during the closure, projections indicate there will be 16 hours of freeway congestion on and near the I-5 Bridge and backups as long as 4 miles on each side of the twin spans.
Estimated cost: $13 million. Webpage: interstatebridge.org.
• Ramp meters: This project includes traffic cameras, roadway sensors, electronic message and ramp meters.
Ramp meters are mini-signals used during rush hour and other peak travel periods to control the frequency of vehicles entering the freeway. Typically, ramp meters give alternate green lights to two lanes of vehicles queuing to get onto the freeway.
Ramp meters will be installed at 78th Street, Main Street, state Highway 500/39th Street, Fourth Plain Boulevard and Mill Plain Boulevard. The existing ramp meter at Highway 14/Washington Street also will be upgraded.
Other improvements will allow WSDOT to better monitor traffic flow at the agency’s Traffic Management Center in Vancouver. Electronic message signs over the roadway will provide information about weather, congestion or bridge lifts, and lane closures due to stalled vehicles, crashes, police activity or freeway maintenance.
Tamara Greenwell, WSDOT’s acting communications manager in Southwest Washington, said the project will require an overnight closure of I-5 south of 99th Street so crews can install gantries over the freeway.
“We can’t safety install them with traffic moving underneath,” she said.
Estimated cost: $6.11 million. Webpage: wsdot.wa.gov/projects/i5/sb-interstate-br-ne-78th.
• Bus on shoulder: To improve transit travel times, improvements will be made to the left shoulder of Interstate 5 southbound between 99th Street and the Interstate 5 Bridge so C-Tran buses can use the shoulder during congestion.
The bus-on-shoulder lane will be used during peak periods to maintain a reliable transit schedule. The project will be similar to WSDOT’s existing bus-on-shoulder lane along state Highway 14 and offer a lower-cost way to fully use freeway capacity and improve transit service.
Only licensed professional bus drivers will be allowed to use the bus-on-shoulder lane at low speeds to bypass heavy traffic. Transit drivers will be trained in the lane’s operating rules and how to make complex decisions while driving on the shoulder.
Estimated cost: $6.13 million, from a C-Tran grant. Webpage: wsdot.wa.gov/projects/i5/southbound-bus-shoulder.
• Mill Plain Boulevard corridor improvements: WSDOT intends to improve portions of Mill Plain Boulevard/state Highway 501, between I-5 and the Port of Vancouver. Currently, oversized freight traffic must divert onto city streets because of high points in the roadway and limited overhead clearance.
Planned improvements include reconstructing sections of the roadway, replacing traffic signals, upgrading pedestrian sidewalk ramps, and adding buffered bicycle lanes.
Two intersections on Mill Plain Boulevard, at Washington and Main streets, will be reconstructed. Traffic signals will be replaced at Broadway, Columbia and Main streets.
Estimated cost: $7 million. Webpage: wsdot.wa.gov/Projects/SR501/i5toportofvanimprove.
Greenwell said WSDOT intends to finish the ramp meters and bus-on-shoulder project, as well as substantial work on the Mill Plain corridor improvements, before trunnion replacement in September 2020.
Wednesday’s open house will feature stations so attendees can focus on one or more project. Short videos will be available for the trunnion replacement and ramp meter and technology project.