A failure analysis case study: Structural steel sign post collapse

On May 30, 1987, a 10.1m structural steel sign post collapsed during a wind storm resulting in personal injuries to one person. Because of the injury and resulting litigation, an analysis of the steel post failure was required. The investigation, which began 21 months after the event, was hampered because the in-situ portion of the ruptured post had been capped with a welded steel plate and the remaining portion had been exposed to atmospheric corrosion. Even so, the combined evidence of site investigations, metallographic, mechanical properties, and stress analyses reveal a clear picture of the failure mode.