6. The construction of the Quebec Bridge cost 85 lives after, on two separate occasions, the structure collapsed due to engineering oversights and miscalculations
As early as 1852, the concept of a bridge over the Saint Lawrence River between the cities of Sainte-Foy and Lévis in Quebec, Canada, was a popular project. After many years of planning, on August 29, 1907, as the bridge neared completion, it suddenly collapsed. Killing 75 of the 86 workers on the bridge when the central section tore loose, calculations made in 1904 had not been updated after the scale of the bridge was finalized. As a result, the bridge as it was eventually built was unable to support its own weight; this flaw had been noticed by the site engineering team, who were rebuffed by the project’s chief engineer.
After producing a new design, construction was restarted on a replacement bridge to span the river. On September 11, 1916, as the central bridge span was being raised into place, it collapsed, killing 13 workers. Despite immediate fears of German sabotage, it quickly became apparent that engineering negligence was, once again, at fault. The chief engineer, Ralph Modjeski, had been made aware that the span could not sustain the necessary weight but failed to act on the information. Eventually, after a total of 85 deaths and two critical failures, the Quebec Bridge opened to the public on December 3, 1919.