The closure of the Hood Canal Bridge following a marine crossing didn’t go as planned on July 10 in the Puget Sound. During the process to close the bridge, a mechanical malfunction—later traced to human error—on the west half of the bridge became stuck, closing the bridge to Olympic Peninsula traffic without actually closing the lift span of the bridge.
The State Route 104 bridge experienced the malfunction on the west half as it was nearing a complete closure, which required Washington State Dept of Transportation workers to manually close the bridge. The process took several hours. Once the bridge was successfully placed back into position, engineers inspected the structure and found no reason not to open it back to traffic later in the day.
Further investigation led to a finding of human error, not a faulty part, as the culprit for the seven-hour closure.
“It’s a humbling experience to have thousands of people know about, and be unhappy about, one’s mistake,” says a WSDOT blog post on the incident. “But we know it’s our responsibility to be forthright and accountable for our actions in operating and maintaining our state’s highways and bridges.”
During routine preventative maintenance on the Hood Canal Bridge last week, a valve was inadvertently left closed on one of four hydraulic lift cylinders, which raise and lower sections of the bridge during marine openings. When the valve was left closed, it limited the supply of hydraulic fluid to the cylinder, causing the lift span to rise unevenly during an 8 a.m. opening on Sunday.
As a result of the 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, such as placing signs on the valves as a reminder.
Follow Tim Newcomb on Twitter at @tdnewcomb.