Weekend closures of SR 107 bridge in Montesano

Bridge closures

The State Route 107 bridge over the Chehalis River in south Montesano was closed to all traffic starting at 6 p.m. Friday, the first of three complete weekend closures as contractors work to rehabilitate the 60-plus-year-old bridge.

The first closure marks “a key milestone” in the $23.7 million project, said the state Department of Transportation’s Christina Werner. “In order to reach that milestone, travelers will want to plan ahead for a total bridge closure and adjust travel plans.”

The bridge is scheduled to be closed from 6 p.m. Friday, Sept. 25, to 6 a.m. Monday, Sept. 28. Two additional weekend closures will be announced as they are scheduled. Travelers will be detoured via Highway 101 through Cosmopolis, a roughly 10-mile detour.

Contractor crews working for the Washington State Department of Transportation will close the highway approaching the bridge to switch traffic onto the newly constructed portion, reconfigure concrete barriers and make adjustments to the temporary traffic signal.

The move to the new bridge portion on the east side of the bridge requires traffic to be completely off the roadway, away from heavy machinery, said Werner. Emergency response vehicles will not be able to pass through the construction zone.

The bridge rehabilitation project, which has been underway since spring 2019, replaces deteriorating timber that supports the roadway leading up to the bridge, installs modern safety rails and repaints the entire steel structure to protect against corrosion.

Construction on the $23.7 million bridge project began in May 2019. Rognlin’s Inc. crews have been removing the old timber pilings and replacing them with 6-10-foot diameter concrete supports sunk deep underground. When completed some time in the spring of 2021, the 713-foot concrete structure will have 36 concrete girders, more than 2,600 linear feet of new railing, a new roadway surface, and a higher archway at the south end of the bridge.

Blue Slough Road remains closed for its paving and straightening project and is scheduled to reopen by late October. On 101 at Cosi Hill, the highway shrinks to one lane of alternating traffic regulated by a stop sign since last winter’s slide wiped out one lane.