Load restriction lifted from Wishkah Bridge
Local truckers will be pleased to learn that the Washington State Department of Transportation has lifted a load restriction on the US 12 Wishkah River Bridge in Aberdeen.
Effective immediately, WSDOT will grant qualifying truckers permits to haul overweight loads up to 22,000 pounds per axle. Previously, a load restriction had prohibited truckers hauling loads over 19,000 pounds per axle from using the bridge.
The change in the bridge’s load rating is the result of an in-depth analysis and physical testing of a key crossbeam in the bridge’s structure. WSDOT materials engineers drilled cores from the crossbeam’s concrete and tested its compressive strength.
“The results were amazing,” said Harvey Coffman, WSDOT bridge preservation engineer. “We found that the concrete in the crossbeam was almost twice as strong as we expected. In a bridge over 87 years old, that finding is quite impressive.”
WSDOT conducted the tests following concerns from local trucking companies that overweight restrictions on numerous bridges around Aberdeen were hindering commerce. After meeting with trucking representatives to identify key trucking routes, WSDOT subsequently looked more closely at load-restricted bridges on SR 107, SR 105, US 12 and US 101.
Bridge preservation engineers have identified fixes needed to lift the load restrictions on those bridges, which range from repairs by WSDOT crews to full bridge replacements. The needed repairs and bridge replacement projects will move forward as resources allow. In the case of the Wishkah Bridge, the test results showed the restriction could be lifted immediately.