EVENT
Silver Bridge Collapse
The December 15, 1967 collapse of a highway suspension bridge over the Ohio River, caused by a single eyebar whose internal crack was invisible to inspection — the canonical demonstration that a standing structure is not proof of understanding but only proof that the hypothesis has not yet been refuted.
On the afternoon of December 15, 1967, during rush-hour traffic, the Silver Bridge carrying U.S. Route 35
between Point Pleasant, West Virginia, and Gallipolis, Ohio, collapsed without warning. Forty-six people died. The bridge had been carrying traffic for thirty-nine years. Its design, which used eyebar chains — flat steel links — to support the deck, was considered sound. The collapse was traced to a single eyebar in which a small crack, initiated by corrosion and stress, had grown over decades until the remaining cross-section could no longer carry the load. The crack was located inside the pinhole where the eyebar connected to the next link. It was invisible to external inspection. No protocol existed for inspecting the interior of eyebar pin connections. The hypothesis embedded in the design — that eyebar chains could support a highway bridge for an indefinite period without inspection access to the