HOOD CANAL — Initial investigations reveal that human error was responsible for an uneven lift span on the State Route 104 Hood Canal Bridge on July 10, which caused an unplanned seven-hour bridge closure to marine and vehicular traffic.

The uneven lift span resulted from a malfunction of one of four hydraulic lift cylinders that raise and lower that section of the bridge. The lift didn’t have enough hydraulic fluid present, which is controlled by a valve that was inadvertently left closed following preventive maintenance activities earlier in the week. The malfunctioning hydraulic lift caused the lift span to rise unevenly during an 8 a.m. marine opening on Sunday.

“We are so sorry for the inconvenience and travel disruptions this incident caused to mariners and motorists alike,” said Troy Cowan, WSDOT Olympic Region Assistant Regional Administrator of Maintenance and Operations. “Our crews take great pride in their maintenance of the Hood Canal Bridge. This mistake is a humbling reminder of how important their work is, and how important it is for them to be focused and diligent at all times.”

When the incident occurred on Sunday, WSDOT bridge engineers and additional bridge crew members arrived on scene and manually lowered the span to its closed position. The bridge was then inspected for damage before it was reopened to traffic. Initial assessments revealed only minor damage limited to a few broken bolts used to mount a broken electrical limit switch.

As a result of yesterday’s incident, policies for opening the lift span will be revised to include more quality-assurance checks and additional test openings of the span following specific maintenance procedures.

“We are taking these steps to ensure that this type of event does not occur again, as we understand how vital this bridge is to Olympic Peninsula residents and businesses,” said Cowan.

Visit the WSDOT Blog at wsdot blog.blogspot.com for more information.

— Edited by Michelle Beahm