The Washington State Department of Transportation (WSDOT) yesterday announced an immediate, full closure of the U.S. 101 Simpson Avenue Bridge because of concerns about its structural integrity. The closure will remain in place until further notice.

“We’ve found severe degradation of piles in the easterly pier,” said Kevin Dayton, WSDOT region administrator. “We have no choice but to put safety first and keep traffic off the bridge.”

During the closure, motorists will detour onto the Riverside Bridge, which will be reconfigured to accommodate two-way traffic.

The 83-year-old bridge carries 15,000 vehicles a day over the Hoquiam River. Traffic increases noticeably between May and October as tourists visit nearby ocean beaches via U.S. 101.

“We recognize that closing the bridge creates a hardship for the community, and we will work with city officials and legislators to find a solution as quickly as possible,” Dayton said.

WSDOT hired divers on Tuesday to examine the bridge piers 35 ft underwater after WSDOT crews in recent weeks noticed unusual movement on the bridge. After removing a portion of the cofferdam that construction workers sank into place in the mid-1920s, divers were able to see scouring, marine boars and worm infestation, which led to the degradation of the piles—all of which factored into the engineer’s decision to close the bridge.

In-water pier inspections are conducted on a five-year cycle. The last underwater inspection on the Simpson Avenue Bridge took place in January 2008.