Group 13:
Lee Murray
David Deally
Brian Gillis
Dermot Casey
The Quebec Bridge Collapses
Engineer of great renownFormer Director of American Society of Civil
EngineersHugely experiencedUnrivalled tender for consultancy roleProject was to be his “crowning achievement”Proud, confident
Theodore Cooper
Quebec was isolated by the St. Lawrence River
Limited financesInexperienced chief engineer – Edward Hoare
The Quebec Bridge Company
Tender by Phoenix Bridge CompanyCooper: Phoenix tender “best and cheapest”
option1600ft cantilever span – longest in the world
Design: 1897-99
1600ft span extended to 1800ft – reduced ice flow impact
At least one year to be saved on construction timeNo recalculations doneSpecifications modified to reduce superstructure
costsApproved immediately, without question
Redesign...
No research or testing done on supporting massive span
Quebec Company could not provide funds for research
Assumed Cooper’s experience and authority sufficient
Construction: Substructure 1900-03
Canadian Government funding providedDetailed drawings commissioned, rushedNo re-computations of bridge weight doneCooper accepted Phoenix estimatesRefused assistance of government engineers
Superstructure: 1903-07
Cooper visited just 3 times – the last in 1903Appointed new graduate Norman McLure as site
engineerCooper only authority to make decisions
On site
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...
The Road to Collapse...
5:30pm, August 29 1907...
5:30pm, August 29 1907...
2 compression members failedCollapsed suddenly75 killed
Collapse
2nd Collapse
Similar design, but 2 ½ times heavierPrefabricated central span dropped into river
during placement11 killed
2nd Collapse: 1916
The Bridge Today