Quebec Bridge
The Quebec Bridge is located on the lower Saint Lawrence River where the river narrows west of Quebec City, Quebec, Canada. A steel truss cantilevered structure, it presently accommodates both highway and rail traffic and at one time also handled a streetcar line.The bridge was built by the "Qubec Bridge and Railway Company," a federal-owned corporation as part of the government's National Transcontinental Railway, and construction began in 1903 after the federal government allocated funding. It was designed to span the river's shipping lane and measured 26.5 metres (67 feet) wide, carrying 2 railway tracks, 2 streetcar lines, and a 2-lane road.
By 1904 the structure was taking shape, however due to miscalculations made during the planning stages, the actual weight of the bridge was far in excess of its carrying capacity. When the bridge was nearing completion structural problems were noticed but the local engineering team did not recognize the gravity of the situation. Work continued despite the fact that the consulting engineer ordered all work to be halted. On August 29, 1907, after four years of construction, the South Arm and part of the central section of the bridge collapsed into the river in just 15 seconds. Of the 86 workers on the bridge that day 75 were killed and the remainder were injured.
After a Royal Commission of Inquiry into the collapse, construction started on a replacement second bridge following a similar design, however disaster struck again when the prefabricated centre span fell into the river while being raised into position on September 11, 1916, killing eleven men. Construction was ultimately completed in August of 1919. Finally, on December 3, 1919 the second Quebec Bridge opened for rail traffic, after almost 2 decades of construction at the site 10 kilometres (6 miles) upstream from Quebec City. Its center span of 576 metres (1890 feet) remains the longest cantilevered bridge span in the world and is considered a major engineering feat with the bridge having been declared an historic monument in 1987 by the Canadian and American Society of Civil Engineers. On January 24, 1996 it was declared a Canadian National Historic Site.
Of general interest, a portion of the collapsed bridge has been used over the past century to smelt rings used in the Iron Ring issued in the Ritual of the Calling of an Engineer ceremonies, administered by The Corporation of the Seven Wardens Inc. for graduating Canadian engineering students. These portions of the collapsed Quebec Bridge, carried on the little finger of the working hand of every Professional Engineer (P.Eng.) in Canada are meant to serve as a reminder to engineers of their social responsibilities to follow the ethical requirements of their profession.
The Pierre Laporte Bridge (suspension bridge) opened in 1970 just upstream to accommodate highway traffic on Autoroute 73.