The Suspension Bridge: Silver Bridge Collapse

The Silver Bridge was a suspension bridge built in 1928 and named for the color of its aluminum paint. The bridge linked Point Pleasant, West Virginia and Gallipolis, Ohio, over the Ohio River. The chain eyebars are redundant in two dimensions. This is an early suspension bridge still in service. Other bridges of similar design include the earlier road bridge over the Menai Strait built by Thomas Telford in 1826. The bridge failure was due to a defect in a single link, eyebar 330, on the north of the Ohio subsidiary chain, the first link below the top of the Ohio tower.

On December 15, 1967, the Silver Bridge collapsed while it was full of rush-hour traffic, resulting in the deaths of 46 people. 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 deep. Analysis showed that the bridge was carrying a lot heavier loads than it had initially been designed for and had been poorly maintained.