Built 1928, The Silver Bridge was an eyebar-chain style bridge and named for the color of its aluminum paint. The Silver Bridge went over the Ohio River to Gallipolis, Ohio.
December 15, 1967, the Silver Bridge collapsed while it was full of rush-hour traffic, resulting in the deaths of 46 people. Two of the victims were never found.
Investigation of the wreckage pointed to the cause of the collapse being the failure of a single eye-bar in a suspension chain, due to a small defect 0.1 inch (2.5 mm) deep. The bridge was carrying much heavier loads than it had originally been designed for and was poorly maintained.
The Silver bridge was replaced by the Silver Memorial Bridge, which was completed in 1969.
Engineering historian Henry Petroski's 2012 book To Forgive Design, finds it "a cautionary tale for engineers of every kind.”
"As a result of the thoroughness of the investigation, the cause of the disaster was precisely and indisputably found to be "a design that inadvertently made inspection all but impossible and failure all but inevitable. If ever a design was to blame for a failure, this was it."
He does not fault the bridge's designers, who were ignorant of many of these hazards. Instead he points to the future.
"If there is anything positive about the Silver Bridge failure, it is that its legacy should be to remind engineers to proceed always with the utmost caution, ever mindful of the possible existence of unknown unknowns and the potential consequences of even the smallest design decisions."
Silver Bridge Photo Gallery
Diagram of where the eyebar broke
How it went together
Close up of fracture
Close Up Of The Fracture
Eye Bar That Broke
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