The Quebec Bridge Collapse August 29, 1907 By: Dan Ford
Purpose for the bridge The St. Lawrence River became a barrier to east-west transportation Montreal’s success was appealing So in 1887, the Quebec Bridge Company was formed
The Hired Help The Phoenix Bridge Company of Phoenixville, Pennsylvania was given the contract The Head Engineer of the project was Theodore Cooper One of the most respected bridge builders at the time
The Original Design Cantilever superstructure with two main supports placed 1600 feet apart Weighed a total of 62 million pounds Cooper said that this would be the best and cheapest plan and proposal
A Change in Plans Before construction was to begin Cooper lengthened the span from 1600 ft to 1800 ft He also modified specifications that would allow for higher unit stresses There was no preliminary tests or research studies conducted to check these design changes
Construction Erection of the superstructure got underway in the summer of 1904 Due to Cooper’s health issues he only visited the site of the bridge 3 times This left a lack of authority on the construction site
Troubles During Construction The actual weight of steel put into the bridge had far exceeded the original weight compressive chords 7-L and 8-L of the south cantilever arm were bent On August 27, 1907, it was reported that the deflection in chord 9-L had increased from three-quarters of an inch out of line to two and one-quarter inches in just a weeks time Yet construction continued!!
The Collapse: August 29, 1907
Reasons for failure Financial troubles with the Quebec Company - Inaccurate theoretical estimates of the bridge's weight - Unchecked changes i.e. Cooper’s high-regard
The Aftermath Of the 86 men who were still on the bridge at the time of the collapse only 11 survived The Royal Commission attributed the failure to defective design and errors in the judgment of Theodore Cooper Cooper’s career ended, and as a result he retired from public life and died in his home on August 24, 1919, at the age of eighty.
The End