Bump on Knik River bridge joints is a permanent snowplow safety feature

 What you need to know:

• A connection joint between the Knik River bridge and the highway will remain rough because it’s part of the permanent design. The joints sit just below the road surface to protect them from snowplows. 
• An additional bump, created by faulty new asphalt near the bridge, will be smoothed out as part of adjustments scheduled for after the state fair.
• The Knik River bridge project is expected to be completed before snow flies. A similar project is scheduled for the Peters Creek bridge next year.

PALMER — A section of the Knik River bridge that some drivers expected to see fully smoothed after recent upgrades will remain rough as part of the project’s permanent design, state officials said Tuesday.

Some drivers feel a jolt while traveling over the metal connectors between the bridge decks and the roadway because the joints sit about half an inch below the road surface, Alaska Department of Transportation project manager Jason Lamoreaux said in an interview. 

The placement is designed to make sure snowplows don’t catch on them, an issue that can damage both the road and plow blade, he said. 

“There have been other instances where we’ve had a similar joint that was essentially flush, and within the first winter, it was torn up and needed to be replaced again,” he said. “So we’re avoiding that by having it set down so the plows don’t hit them.”

Drivers who notice a dramatic bump may actually be feeling a combination of road conditions, Lamoreaux said, including a section of pavement slated for a redo about 20 feet away from the joints.

That asphalt is designed to create a smooth approach to the joints but didn’t lay well and needs to be fixed, he said.

“I have a feeling people are not differentiating between that whole section — they are maybe not recognizing there are multiple things happening as you’re going from the existing roadway where we didn’t do anything,” he said. “There’s always going to be a bump and movement there because you’re going from a rutted surface to a flatter surface.”

Repairs to the pavement before and after the bridge work zone are included in a major 33-mile Glenn Highway overhaul expected to be completed in three stages between next year and 2031.

Repairs on the roughly 200-foot sections are scheduled for after the State Fair and will include some lane closures, he said.

Both bridge spans reopened to travel in early July while officials continued final work through the summer. That included placing a polyester-concrete overlay on the bridge decks that will prevent rutting over time, he said.

Crews also dug out a series of paved median crossovers used to detour traffic over the course of the project.

Project officials initially planned to leave those in place for future use during emergencies or bridge repairs but ultimately removed them because they could lead to water pooling on the highway, Lamoreaux said.

Crews will next shift work south to the Peters Creek bridge, where a similar project is expected to temporarily close bridge spans for refitting next summer.

-- Contact Amy Bushatz at contact@matsusentinel.com

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