1. Quebec Bridge Collapse

2. Head Engineer Head Engineer: Theodore Cooper
Highly respected reputation
Wanted a monumental project to end his career
Unrivalled for the tender
Overconfident

3. The Quebec Bridge company
Lack of funds
Never built a bridge with a span larger than 300 feet
Wanted “quickest and cheapest” solution

4. Cooper only visited the site 3 times
Cooper appointed, Norman McLure, with no experience, to be his eyes and ears on site.

5. Pre-Construction No preliminary tests and research studies done
Bridge was extended an extra 200 feet without any calculations
No recalculations of assumed weights for the bridge after revised specifications
Theoretical estimates of weights used

6. Construction continued without dead load being calculated
Phoenix Bridge Company’s inspector of materials projected weight of the steel was 11 million pounds heavier than previously estimated.
Cooper concluded that Edwards was wrong by 7 to 10%.
This was after much of the bridge was fabricated or in place

7. During Construction Horizontal compression members started deflecting
Unable to line up members for riveting
As span increased many weight-bearing lower chords were still unriveted
Eventually two of the chords from the south cantilever arm bent

9. Chief engineer in Phoenixville insisted that these chords were bent when they left the shop and that they were still serviceable
Cooper sent word to Phenoix Bridge Company to suspend construction which was ignored

10. Collapse

11. Two compression cables failed.
Sudden collapse!
75 were killed

12. 2nd Collapse A second collapse occurred in 1916
Similar design but two and a half times heavier than its predecessor
During the construction the central span which was pre-fabricated dropped into the river while being lifted into place
11 men died.