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