About Bridges: Retrofits, repairs, and construction for this critical infrastructure.

• Author: Simonelli, Isaac Stone
• Position: CONSTRUCTION

With about 365,000 miles of river and thousands more miles of streams and other waterways--not to mention 6.640 miles of coastline--bridges are vital infrastructure for keeping Alaskans moving along the state's roadways.

"You've got to understand the geography of Alaska: to get from point A to point B, there are rivers, streams, and creeks. Everything that is fish-bearing and things of that nature has to have a bridge over it," says Bud Courtright, a senior project manager for Swalling General Contractors, which specializes in bridge building. "In the old days, they drove across them; 1 think we've finally grown out of that mindset."

And while some smaller, fragile stream systems might have once been crossed without a bridge, there are many water crossings in Alaska where such attempts are unimaginable without a bridge--or a boat.

More than $80 million has been spent on bridge retrofits, repairs, and construction in the Last Frontier since 2019, explains Richard Pratt, chief bridge engineer for the Alaska Department of Transportation & Public Facilities (DOT&PF).

A number of bridge projects will be under construction in 2021, including the replacement of two bridges along the Chena River, the replacement of the bridge on Old Sterling Highway over Anchor River, and the replacement of five bridges on the Seward Highway.

"Replacements are typically condition and cost-based decisions," Pratt says. "If we have a bridge within the limits of a highway rehabilitation project, we wilt compare the life cycle cost of rehabilitation versus replacement. We also include some consideration of improving the anticipated performance of a bridge designed to meet current standards versus a lower cost rehabilitation strategy."

A new bridge--instead of a replacement--is often required due to expanding highway systems.

"For example, we need new bridges on the Sterling Highway because we're constructing several miles of new alignment for the Cooper Landing Bypass. We also build new bridges to improve safety such as replacing an at-grade railroad crossing with a grade separation structure," Pratt says.

Cool--But Not Record Setting

The new Juneau Creek Bridge for the Cooper Landing Bypass Project on the Sterling Highway, which has been more than forty years in the coming, sits at about 30 percent design as of March, with expectations that geotechnical exploration will provide the necessary information to take it to 75 percent by the fall.

The bridge, which has...