Update: County roads department hosts open house Wednesday on emergency closure of Tolt Hill Bridge

UPDATE: King County Road Services will host a community meeting, 7 to 8:30 p.m. Wednesday, June 21 at Tolt Middle School to discuss the emergency closure of the bridge. The meeting is an open house; participants can drop in at any time.

ORIGINAL: King County Road Services Division has scheduled an emergency closure of Tolt Hill Bridge, on Northeast Tolt Hill Road, over the Snoqualmie River, west of the city of Carnation.

The bridge was completely closed to traffic Friday and detour routes were established.

The closure is related to changes in federal highway laws and bridge load ratings, following the 2007 collapse of the eight-lane bridge on Interstate 35W in Minnesota. The new requirements for construction require all bridges to be load rated using the new criteria by 2022.

For the first time, agencies are now required to review gusset plates, which are thick sheets of steel that connect structural elements of truss bridges.

There are about 36,000 bolts fastening the plates on the two 300-foot long steel trusses of the Tolt Hill Bridge.

King County had structural engineers review the work of the private contractor who designed the Tolt Hill Bridge. They discovered discrepancies between the design calculations and the actual construction.

The bridge currently shows no visible issues, and has been inspected on a biweekly basis since March 8. The last inspection was June 13.

No dates have been set yet for repair work or reopening the bridge.

Details on the repair work and schedule will be posted on the county’s webpage, when they are determined. The page will include updates and photos.

Sign up for emails or text alerts by clicking the red “Stay Connected” button.

The Tolt Hill Bridge is owned and maintained by King County. The bridge opened May 30, 2008, replacing the original bridge, built in 1922.