1. The Quebec Bridge Collapse August 29, 1907
By: Dan Ford

2. 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

3. 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

4. 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

6. 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

7. 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

8. 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!!

9. The Collapse: August 29, 1907

10. 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

11. 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.

12. The End