Glenn Highway bridge to close for 45 days starting Saturday

What you need to know:

• The northbound Peters Creek Bridge on the Glenn Highway will close for major repairs starting Saturday, affecting more than 38,000 daily drivers between Mat-Su and Anchorage. The closure is scheduled to last 45 days.
• Traffic will be rerouted onto the southbound span using a movable barrier system that shifts twice daily to prioritize peak traffic flow.
• The project is needed to address significant wear on the aging northbound span. Officials said a similar detour setup last year during Knik River Bridge construction caused only minor delays. 

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A construction project set to begin this weekend will shut down a Glenn Highway bridge for more than a month, triggering slowdowns and some delays for thousands of drivers who travel daily between Mat-Su and Anchorage.

The northbound span of the Peters Creek Bridge between miles 20 and 21 of the Glenn Highway will close for about 45 days while crews remove about 2 inches of concrete, reconstruct the surface, and apply a smooth overlay, state transportation officials said in an interview.

The closure is scheduled to begin Saturday, with reopening targeted for early June, they said. 

More than 38,000 vehicles travel northbound through the area each day, according to state traffic data.

During the work, northbound traffic will be diverted into three lanes on the southbound bridge span. The lanes will be reconfigured twice daily using a barrier-moving machine to allow for two lanes of travel in the direction with the heaviest traffic flow. The barriers will be shifted early each day before the morning commute, and again around noon, officials said.

The closure and detour plan mirrors a system used during a related project last summer that closed sections of the Knik River Bridge in Mat-Su for about two months. 

Transportation officials planned for worst-case scenario traffic impacts during that project, but users instead found the work paired with the barrier moving system added mere minutes to most drives through brief delays or because of the speed limit slowdown to 45 mph through the work zone, travelers and officials said in interviews last year.

Unlike the Knik bridge construction, which included work on both northbound and southbound sections, the Peters Creek Bridge project affects only the more than 50-year-old northbound span. The southbound Peters Creek span is newer and does not need major repairs, said Alaska Department of Transportation construction manager Jason Lamoreaux, who is overseeing the $20 million federally funded project.

“The northbound bridge is significantly worse as far as wear and tear,” he said. “We’ve been doing Band-Aid fixes on it for a long time — new membranes, new overlays, patchwork here and there. It’s needed a significant overhaul for a long time. And this is our opportunity to do that.”

While the 156-foot Peters Creek Bridge is significantly shorter than the Knik bridge, which stretches 1,500 feet, the diverted lanes before and after the construction zone are longer than those used last year, Lamoreaux said. Hills and a curve leading in and out of the construction zone mean drivers need more distance to move safely through the detour, he said.

Project work will begin now instead of waiting for sunny summer weather so the long closure does not extend over a holiday weekend, he said. Drivers can help reduce backups by following merge signs and fully using open lanes until the closure point, rather than queuing in advance, he said.

-- Contact Amy Bushatz at contact@matsusentinel.com