Lee Murray

1
The Quebec Bridge Collapses

• Group 13
• Lee Murray
• David Deally
• Brian Gillis
• Dermot Casey

2
Theodore Cooper

• Engineer of great renown
• Former Director of American Society of Civil
  Engineers
• Hugely experienced
• Unrivalled tender for consultancy role
• Project was to be his crowning achievement
• Proud, confident

3
The Quebec Bridge Company

• Quebec was isolated by the St. Lawrence River
• Limited finances
• Inexperienced chief engineer Edward Hoare

4
Design 1897-99

• Tender by Phoenix Bridge Company
• Cooper Phoenix tender best and cheapest option
• 1600ft cantilever span longest in the world

5
Redesign...

• 1600ft span extended to 1800ft reduced ice flow
  impact
• At least one year to be saved on construction
  time
• No recalculations done
• Specifications modified to reduce superstructure
  costs
• Approved immediately, without question

6
Construction Substructure 1900-03

• No research or testing done on supporting massive
  span
• Quebec Company could not provide funds for
  research
• Assumed Coopers experience and authority
  sufficient

7
Superstructure 1903-07

• Canadian Government funding provided
• Detailed drawings commissioned, rushed
• No re-computations of bridge weight done
• Cooper accepted Phoenix estimates
• Refused assistance of government engineers

8
On site

• Cooper visited just 3 times the last in 1903
• Appointed new graduate Norman McLure as site
  engineer
• Cooper only authority to make decisions

9
The Road to Collapse...

• February 1906 Cooper is advised that steel in
  bridge was projected to be over 1million lbs over
  initial estimates
• August 1907 McLure advises horizontal
  compression members deflecting, unable to line up
  for rivetting eventually members bent
• Phoenix Co insist chords bent on leaving shop,
  McLure insists bend has increased on site
• Aug 29th Cooper sent word to Phoenix to cease
  works ignored...
• No word sent to Quebec...

10
530pm, August 29 1907...
11
530pm, August 29 1907...
12
Collapse

• 2 compression members failed
• Collapsed suddenly
• 75 killed

13
2nd Collapse
14
2nd Collapse 1916

• Similar design, but 2 ½ times heavier
• Prefabricated central span dropped into river
  during placement
• 11 killed

15
The Bridge Today