Saturday, July 11, 2009

Honshu-Shikoku Bridges: Kurushima Bridge (2)

Bridge building can be a dangerous profession. There were 27 deaths building the Brooklyn Bridge including the death of the designer, John Roebling. There were 16 deaths building the Sydney Harbor Bridge.

The Kurushima Bridge was designed so that some of the back spans (spans 6, 7, and 9) were supported on piers rather than from the suspension cables. These spans were incrementally launched from the anchorages onto temporary steel platforms. A week before we visited the bridge, they were dismantling a platform when it suddenly slipped from it's cables, sending seven workers to their death. After the accident, the platform lowering system was replaced using ground-based cranes.

Unfortunately, it sometimes takes an accident before improvements can be made. A safety commission conducted a study of the accident and made recommendations to improve the safety of this widely used incremental deck launching system.

Although bridge construction remains a dangerous profession (about 60 deaths per 100,000 workers) it is eclipsed by pilots (70 deaths per 100,000 workers), fishermen (71 deaths per 100,000 workers), and loggers (118 deaths per 100,000 workers).
Creative Commons License
Honshu-Shikoku Bridges: Kurushima Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

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