State expects seismic retrofit of Tanana River Bridge at Big Delta to start in mid-October

The Alaska Department of Transportation and Public Facilities expects to begin seismic retrofit work on the Tanana River Bridge at Big Delta in mid-October, according to the Northern Region's final construction newsletter of the season, released Monday.

The bridge carries the Richardson Highway over the Tanana River near Delta Junction. A seismic retrofit strengthens an existing bridge rather than replacing it. A 2012 department report calls Alaska the most seismically active state in the union and says the goal of the retrofit program is to prevent bridge collapse during an earthquake.

Big Delta is one of eight bridges in the project. The others include crossings of the Tanana River at Nenana, the Copper River at Chitina, the Klutina River at Copper Center and the Little Salcha River.

The Federal Highway Administration has obligated $3.64 million to the state for the work, federal spending records show. When the department put the project out to bid in April, its engineers estimated the cost at $5 million to $10 million, Alaska News reported in August. The bid documents call for construction to finish by Oct. 31, 2027.

The newsletter did not list lane closures or work hours for the bridge. Drivers can check Alaska 511 for current conditions.