The Washington State Department of Transportation closed the westbound lanes of State Route 16 and the Olympic Drive overpass Sunday for several hours after a semi truck carrying an oversized load hit the bridge’s bottom girder.

According to WSDOT officials, the force of the impact pushed the bottom end girder out of plane and broke the girder along its top flange. Six post-tensioned steel strands in the girder were severed and two others were compromised.

The westbound lanes, and the Olympic Drive overpass itself, were closed to traffic when the accident occurred at approximately 1:15 p.m. At around 5 p.m., WSDOT reopened a westbound shoulder of State Route 16 to one lane of westbound highway traffic as well as the Olympic Drive overpass, but kept the west shoulder and sidewalk of the overpass closed directly over the damaged area. Crews finally reopened all westbound State Route 16 lanes under the Olympic Drive overpass just after 8 p.m. Sunday.

WSDOT bridge engineers will continue to assess damage Monday to determine whether the girder can be repaired or if it must be replaced.