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Catastrophe on the Québec Bridge

For the week of Monday August 26, 2002

on August 29, 1907, the Québec Bridge collapsed for the first time, killing 76 workers. The building of this bridge, which was considered at the time to be the eighth wonder of the world, represents one of the greatest civil engineering feats in Canadian history.

Lift of the centre span of the Québec Bridge<br>September 11, 1916, 10:25 a.m.

Lift of the centre span of the Québec Bridge
September 11, 1916, 10:25 a.m.

© Eugene Michael Finn / Dominion Bridge Company
LAC / PA-149628

At the end of the 19th century, Québec City's development was hindered by an absence of a direct railway link between the north and south shores of the St. Lawrence River. The Québec Bridge Company, founded in 1887, proposed constructing a cantilever bridge near the mouth of the Chaudière River, at the river's narrowest point. The project was ambitious. The plans provided for a span of 548 m between pillars, two diamond-shaped arms, and an arched centre span 45 m above water to allow ships to pass under.

Construction began in autumn of 1900. Seven years later, moments before workers were to leave the worksite, the cantilever arm at the bridge's south end broke and thundered down into the water. Only 11 workers survived the crash. Among the victims who drowned or were crushed under tonnes of steel were Canadians, Americans, and several Aboriginals from Caughnawaga (Kahnawaké).

After identifying the accident's causes, which were attributed to an error in how the weight of the structure was determined, the federal government decided to rebuild the bridge. This second bridge is noted for the innovations of its designers, most of whom were Canadian. For the first time on a long-span bridge (194 m), the K-shaped pillar system, which makes assembly easier and ensures the structure's stability, was adopted. Nickel steel, which is stronger and lighter than carbon steel, was also widely used in tension members.

Québec Bridge on the Saint Lawrence River

Québec Bridge on the Saint Lawrence River
© Parks Canada / J. Beardsell / 1997

The two cantilever arms were completed on September 11, 1916, and then began the delicate operation to secure the centre span. Suddenly, the 4,985-metric ton arch that was suspended a few metres above water, twisted and crashed to the bottom of the river. Thirteen workers perished in this second accident, caused by a support piece breaking from the elevator system. The span was later reconstructed and attached in September 1917, after four long days were spent raising it in front of an anxious public.

After several tests were performed, the bridge was officially inaugurated on August 22, 1919. At 987 m, it remains the world's longest cantilever bridge. A marvel of Canadian engineering, the Québec Bridge has been designated a national historic site.

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