COOS BAY — Monday marked the start of a construction project by Oregon Department of Transportation on the Isthmus Slough Bridge that will continue through fall 2019.
The Isthmus Slough Bridge is a draw bridge that connects Coos Bay and Eastside just beyond where U.S. Highway 101 splits off to Newport Lane.
Problems with the bridge include extensive cracking, exposed rebar on the deck of the westerly approach spans, pack rust in the truss elements, broken welds and missing bolts. The age and wear was noticed during some other replacements to the Isthmus Slough Bridge six years ago. A plan was made back then to address the current issues in a later project.
“Back in 2011, we had a project where the timber pilings holding up the east approach to bridge were replaced,” Project Information Officer with ODOT Dan Latham said.
Construction crews will be repairing the deck and drains of the bridge. Expansion joints will be reconstructed and cracks on the concrete surface of the bridge will be sealed. Workers will also repair welds, replace bolts, remove rust, and replace the draw bridge’s electrical system.
ODOT sent out 2,600 letters notifying Eastside residents of the new construction project. They also spoke with accepted input from local businesses.
“With the earlier project we actually had to close the bridge for two weeks and everybody was detouring down Olive Barber Road. That’s about an eight- or 10-mile detour around. That was a major impact for the all the business and people who lived out there so we kept that in mind when we were planning this project,” Latham said.
ODOT plans to keep both lanes of the bridge open during daylight hours. There will be lane closures at night and around 10 times throughout the project. The bridge will be closed overnight. Lane and bridge closures will last from around 8 p.m. to 6 a.m.
“We’re trying to focus on having the impact at times where people aren’t really driving across the bridge very much,” Latham Said.
Built back in 1931, the Isthmus Slough Bridge has most of the original electrical equipment installed when the bridge was built. One of the repairs unique to draw bridges are the steel grates that raise and lower when a boat comes through.
“We are replacing the steel grates, and the contractor thinks they can do at least one of those grates a night when those bridge closures do happen. If you’ve walked along the bridge, you’ve probably seen the office where they have the draw bridge operator. There’s a lot of really old equipment in there that we’ll be replacing,” Latham said.
Cost of the construction is estimated to be just under $9 million. The bid for the project was awarded to Hamilton Construction Company. Hamilton Construction was contracted for the previous repairs to the Isthmus Slough Bridge.
The Isthmus Slough Bridge has about 8,700 vehicles travel over it every day. The draw bridge opens up to maritime traffic a couple of times a year on average.