The Duplessis Bridge Collapse - January 31, 1951 - An Engineer's Aspect


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Monday, April 29, 2013

The Duplessis Bridge Collapse - January 31, 1951


Around 3am, January 31, 1951, four spans of the one-third-mile steel and concrete Duplessis bridge between Trois-Rivières and Cap-de-la-Madeleine, crashed with a thunderous roar, plunging three persons to their death in the St. Maurice river.

Dr. Conrad Godin tells Pierre Paquette in the Radio Canada archives, that a fourth man also died a few days later while maneuvering a crane to get the car that fell into the waters of the Saint-Maurice.

Image: Two remaining spans of the Duplessis bridge in the foreground and four collapsed spans.


The Duplessis bridge was named after the Premier of Quebec, Maurice Duplessis. Reviled and revered, Maurice Duplessis left no one indifferent to his 32-year reign as Trois-Rivières’ Member of the Legislative Assembly of Quebec, 18 of those as premier (Canadian Geographic).

According to Canadian Geographic, Duplessis was born in Trois-Rivières in 1890 and he ruled the province with an iron fist in the late 1930s and from 1944 until his death in 1959, a period that became known as la Grande Noirceur (“the Great Darkness”).

Canadian Geographic goes on to assert: "Little academic research has been devoted to Duplessis and his politics, given the negative impression he left in the collective memory of Quebecers."

The Duplessis bridge collapsed three years after he inaugurated it in 1948, having declared it to be "as solid as the Union Nationale."


Dr. Conrad Godin, in an interview with Radio Canada, claims that if the collapse of the Duplessis bridge left a lasting impression, this is largely due to Maurice Duplessis. The day of the disaster, launched at the beginning of the session of the Legislative Assembly, Duplessis announced, "I think it is simply sabotage."

Duplessis stubbornly believed subversives were trying to destroy the means of communication between Quebec City, Trois-Rivières and Montreal. But the mayor of Trois-Rivières, as well as the inhabitants of the city, knew the bridge collapse was caused by the poor quality of materials and carelessness of public works of the Unionist government (Radio Canada archives).


The Duplessis Bridge collapse was an incident of brittle fracture. "Four of the eight spans of the welded composite plate girder bridge over Maurice River collapsed in a night at a temperature of minus 34 degrees Celsius. The steel contained 0.4% carbon and 0.12% sulfur. Two fissures in the bridge had been repaired two years earlier using riveted plates to strengthen the welding seams under tension in the flanges. The bridge had undergone a thorough inspection only two weeks before the failure. When it came, the collapse was sudden and completely unforeseen (Failed Bridges: Case Studies, Causes and Consequences, By Joachim Scheer, John Wiley & Sons, Feb 16, 2011, Pages 126-127)."

In his book Fracture and Life, Brian Cotterell takes a more in-depth look at the brittle failure. He says that in the Duplessis Bridge case, the flange plate had been ordered to meet C.S.A. S-40 (ASTM A-7) specifications. Since this structural plates were thick, they should have been rolled from semi- or fully-killed steel, but they were rolled from rimmed steel instead. This rimmed steel contained the concentrations of carbon and sulphur stated above.

Cotterell explains, "Molten steel contains dissolved oxygen and other gases which need to be controlled during solidification. The amount of oxygen can be controlled by the addition of deoxidising agents such as aluminium. In fully-killed steels there is virtually no evolution of gas. With semi-killed steels a small amount of gas is allowed to evolve that benefits the ingot by minimising shrinkage. In rimmed steel the reaction of dissolved oxygen and carbon to form carbon oxide gases is allowed to progress to form an ingot with blowholes of various sizes at its centre with a heavy rim of relatively void-free metal."

Brian Cotterell continues, "During hot rolling the voids in the ingot are welded together. Segregation also occurs in rimmed steels with carbon, sulphur and phosphorus segregating in the centre and top of the ingot. Rimmed steels are cheapest because less of the ingot has to be discarded, but the transition temperature in rimmed steels can be high. Fully-killed steels have the lowest transition temperature. Welding becomes more problematic as the carbon equivalent increases causing embrittlement of the steel and cracking unless measures such as pre-heating are taken."

And finally Mr. Cotterell claims, "The Charpy impact values for the fractured girders of the Duplessis Bridge were only 4-8 J at 38 degrees Celsius. Clearly the rimmed steel was far too brittle and almost guaranteed that the bridge would collapse (Fractures and Life, By Brian Cotterell, Imperial College Press, 2010, Pages 205-206)."

Following are newspaper accounts of the bridge collapse and the fallout afterward:


The Lethbridge Herald, Lethbridge, Alberta, Canada, Wednesday, January 31, 1951, Pages 1 and 2.


4 Known Dead
As Spans Crash
With Great Roar

Four Sections Of
Duplessis Bridge
Buckle Into River

(By The Canadian Press)
THREE RIVERS, Que., Jan. 31--Four spans of the one-third-mile steel and concrete Duplessis bridge crashed with a thunderous roar before dawn today plunging at least four persons to their death in the St. Maurice river.

The roar aroused hundreds of persons who thought an earthquake had struck the city at the confluence of the St. Maurice and St. Lawrence rivers. They ran in bewilderment from their homes in 26-below-zero weather.


The few cars on the bridge at the time--2:55 a.m.--were sent cascading into the ice and water carrying their drivers with them.

Mayor J. A. Mongrain, terming the collapse a "catastrophe" that "could have been avoided," called a special meeting of city council for this afternoon.

In mid-afternoon police said it was pretty well established that only four persons had lost their lives, although it was feared earlier the death toll would double that figure.


Three bodies had been recovered and the search continued for the body of Noel Doucet, iron foundry employee from Cap De La Madeleine, whose automobile was identified beneath the water.

The other dead: Henri Paul Gendron, taxi operator, Cape De La Madeleine; a man, named Beaumier whose first name had not been established, and P. Fiset of Ville St. Laurent, a Montreal suburb.

Fiset's body was not recovered until nearly eight hours after the bridge collapsed.

Earlier reports were discounted that a man named Lemay and an unnamed traveller from Toronto had been killed.

The bridge, each span 180 feet long, connects Three Rivers with its neighboring city of Cap De La Madeleine.

The four arches of the bridge--those nearest Three Rivers on the route over the St. Maurice to Cap De La Madeleine--plunged to the ice below and crushed through into the water without warning.

The car drivers, right on the very spans that crumbled, had no chance to escape.

Police and workers from a foundry near the bridge made attempts by boat to drag the sunken cars from the river but met no success and had to give up their efforts pending daylight and the obtaining of heavier equipment.


Eyewitnesses, most of them taxi drivers either just ready to cross the bridge from Three Rivers to Cap De La Madeleine or already on the bridge heading for Three Rivers, said the crash was a "near miss" for many.

They were able to see the bridge go down, see the cars drop out of sight and stop in time themselves.

First word that the four spans nearest Three Rivers of the $3,000,000 nine-span bridge had collapsed reached Three Rivers from taxi...

(Continued on Page Two)

(Continued from Front Page)

...drivers actually on the bridge at the time.

The collapse occurred in bitter weather--26 below zero.


The spans, part of the $3,000,000 bridge which last winter was closed to heavy traffic for a time after cracks were discovered in its concrete parts, crumbled and fell at 2:55 a.m. EST.

Within a minute, Taxi Driver Maurice Roy, en route to Three Rivers from Cap de la Madeleine, had sent word over his taxi radio.

"I was very nervous and scared," he said "I sent a message to my taxi dispatcher who called the police."

Taxi Driver Jacques Faucher had an even closer call.

"I got the scare of my life," he said. "I was just coming off the bridge when I heard the noise. One minute less and I would have been right with those cars that plunged into the river."

Residents living nearby said the bridge went down with such a noise they thought an earthquake had occurred. Some telephoned the newspaper Le Nouvelliste to see if that was the case.


As the spans fell, they tore out light wires and telephone cables.

Omer Cheney, visibly shaken after his close call, told how he was driving along on the bridge in his car when suddenly all the lights went out.

"Then in the glare of the headlights of my car I could see ahead of me nothingness, broken only by the bare piers of the bridge standing up out of the water. The roadway of the bridge was gone. I put on my brakes and stopped in time.

"All I could see was where the bridge had been."

The bitter cold and the cutting off of the bridge lights hampered police efforts at determining damage, the number of cars lost and the loss of life.

In the early morning darkness newspaper photographers rushed to the scene and beside the crumbled debris of a bridge that had been Three Rivers' pride, took pictures of the automobiles visible in the river, their headlights still on.


Each of the collapsed spans is 180 feet long and the crumpled section of the bridge dipped downward in the middle like some giant wedge, its ends still up at bridge height and supported by steel reinforcements in the concrete superstructure.

Today's collapse appeared a considerable distance from the place where cracks were discovered last winter and repaired.

Leading the efforts to recover the bodies was Mayor J. A. Mongrain of Three Rivers.

Crowds of people from Three Rivers and near Cap de la Madeleine flocked to the scene.

Despite the intense cold there were many offers to help, such as those from a group of foundry workers who attempted long before daybreak to raise one of the sunken cars after going out to it in a boat. Their efforts were in vain.

Police were on the scene within 15 minutes.

Three Rivers is about 90 miles northeast of Montreal.


Fernan Gagnon, night editor of Le Nouvelliste, told how he received word of the bridge collapse. He said there was "a lot of noise like an earthquake."

Then came telephone calls from people who heard the noise and wondered had an earthquake occurred.

Minutes later the taxi drivers on the bridge had relayed the news that one of the prides of Three Rivers--this 1,970-foot bridge--had crashed.

Premier Maurice Duplessis of Quebec officially opened the bridge which took his name as Three Rivers' outstanding son, in June, 1948.

It is a nine-span affair stretching from Three Rivers across the St. Maurice River in six spans to a point of land and then continuing on to Cap De La Madeleine.

The bridge was a wide, concrete affair affording a high-speed thoroughfare between Three Rivers and the neighboring industrial city of Cap De La Madeleine.

The Lethbridge Herald, Lethbridge, Alberta, Canada, Thursday, February 1, 1951, Pages 1 and 2.

Of Bridge
Is Probed

THREE RIVERS, Que., Feb. 1.--(CP)--Four great spans of the Duplessis bridge, once the pride of this thriving industrial city, lay today in the ice-choked St. Maurice River.

On the lips of almost every resident, still shocked by the collapse without warning in yesterday's early-morning darkness of the $3,000,000 steel-and-concrete structure, was the question: "Why?"

Four men died in the disaster, the worst to hit Three Rivers since 1908 when fire destroyed half the city. Only the fact that the collapse came at a period of light traffic prevented what likely would have been a high death toll. Normally the 50-foot-high bridge, main link with Quebec 90 miles to the east, is abustle with automobiles and trucks.


Investigations were under way today to determine responsibility for what Three Rivers' mayor, J. A. Mongrain, termed a "catastrophe." A provincial government inquiry was promised by Premier Maurice Duplessis, who opened the 2,000-foot-long bridge in 1948. The Premier's first reaction, given in a speech to the legislature, was; "Sabotage!" He admitted that he had no evidence immediately to support the charge.

Collapse of four sections of the structure came at 2:55 a.m. as a few automobiles and taxis were crossing to Cap De La Madeleine. The vehicles were tossed wildly and plunged to the ice below amid a roar described by witnesses as like that "of an earthquake."

The victims had no chance to escape as their vehicles, closed tightly against the 26-below-zero weather, plunged into the swift-flowing St. Maurice. For a time, the lights of the submerged automobiles were seen by some survivors on the sections of the bridge still standing. Then they went out.

The Duplessis bridge, named in honor of Premier Duplessis' father,


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former Three Rivers mayor, was closed for a time last February when cracks developed in the steel under structure. Repair work went on for nearly eight months.


Many theories have been advanced as a likely cause of the bridge failure--in Toronto one engineer said metal contraction due
to cold weather could have been the reason--but recovery of the sunken spans seemed necessary before the reason could be determined finally.

The Dufresne Engineering Company of Montreal constructed the bridge, the Dominion Bridge and Iron Company supplying the steel. Engineers from both firms were on the scene awaiting recovery of the collapsed sections, those nearest to the Three Rivers end of the bridge.

The death toll was set almost finally at four. Police said it was possible that more bodies would be recovered, but thought it unlikely.

The Moberly Monitor Index, Moberly, Missouri, February 2, 1951, Page 5.

Denies 'Sabotage'
In Fatal Collapse
Of Quebec Bridge

THREE RIVERS, Que., Feb. 2--(UP)--Suggestions that sabotage might have caused the $3,000,000 Duplessis highway bridge to buckle and collapse were denied last night by Mayor J. A. Mongrain.

The charges were made by Quebec Premier Maurice Duplessis, who declared Wednesday that "subversive elements" were responsible for Tuesday's disaster in which four motorists died.

"No one in Three Rivers believes sabotage had any connection with the disaster," Mayor Mongrain said. "There is nothing to indicate it."

Duplessis has promised that an investigation of the accident will be made.

A Toronto engineer, meanwhile, has suggested that metal contraction during cold weather might be the explanation. It was 26 below zero when the bridge snapped.

The Hutchinson News-Herald, Hutchinson, Kansas, Thursday, February 1, 1951, Page 1.

Sabotage In
Bridge Break?

Three Rivers, Que. (AP)--Nearly half of the new $3 millions Duplessis bridge dropped with a thunderous crack into the St. Maurice river Wednesday.

Four persons, caught in their cars on collapsing spans, fell to an icy death. Quebec Premier Maurice Duplessis charged the bridge was "sabotaged by subversive elements."

The nine-span highway bridge, more than a third of a mile long, was closed to heavy traffic for a time last winter until cracks could be repaired. It was opened in June, 1948, by Premier Duplessis and named for him, a native of Three Rivers.

Premier Duplessis told the Quebec legislature there would be a government inquiry.

He said he believed sabotage was involved for two reasons: First, because of the "timing" in the early morning, and second, because it was "the Duplessis bridge."

He recalled that he is responsible for the Quebec "padlock law," by which establishments suspected of subversive or Communist connections may be closed.

Image: COLLAPSED BRIDGE--This aerial view shows fallen span of Duplessis bridge at Three Rivers, Que., with automobiles it carried with it still resting on it. Four concrete and steel spans of the $3,000,000 bridge plunged into the St. Maurice river with the four cars, carrying at least four persons to their death. Residents of Three Rivers line the frozen river to view the tragic spectacle.

Four 180-foot spans of the bridge collapsed at 2:55 a.m. carrying away telephone lines linking Quebec and Montreal.

Four cars were hurled through the ice by the sudden snapping of the spans, and several other motorists had narrow escapes.


The Lethbridge Herald, Lethbridge, Alberta, Canada, Wednesday, August 29, 1951, Page 2.

Poor Quality
Steel Blamed
For Bridge Crash

THREE RIVERS,Que.--(CP)--Defective and poor quality steel was blamed for the collapse of the $3,500,000 Duplessis bridge here last January.

A representative of the Dominion Bridge Company Limited of Montreal said his company made a detailed report to the provincial department of public works in December, 1950, stating that some of the steel used in construction of the milelong (sic.) link over the St. Maurice River was "poor quality rim steel."

He was appearing before a two-man inquiry commission appointed by the provincial government to determine the cause of the collapse.

Yvan Vallee, deputy minister of public works, acknowledged that the bridge company report was received by his department after several months were spend in stiffening the joints.

He said stiffeners were rivetted to the joints and tension points after fissures appeared in two main girders in February and March, 1950.


The Lethbridge Herald, Lethbridge, Alberta, Canada, Friday, September 7, 1951, Page 11.

Surprised Bridge
Didn't Collapse
Year Before It Did

THREE RIVERS, Que.--(CP)--The chief engineer of the Dominion Bridge Co. said Thursday he had wondered why the Duplessis bridge had not collapsed when fissures first appeared in main girders a year before the structure plunged into the St. Maurice River.

The engineer, Robert Eadie of Montreal, was testifying before a two-man commission inquiring into the bridge collapse last January.

The Dominion Bridge Company was one of five firms that supplied steel for the bridge.

He told the court that his first reaction after viewing the fissures in February and March 1950 had been one of wonderment at seeing the structures still erect.

The Lethbridge Herald, Lethbridge, Alberta, Canada, Friday, September 7, 1951, Page 2.


THREE RIVERS, QUE.--(CP)--Judge Rene Lippe today adjourned to Sept. 13 the hearing into the collapse of the Duplessis bridge here Jan. 31 with the loss of four lives.

The adjournment, second since the hearing began late last month, followed testimony yesterday by Robert Eadie, chief engineer of the Dominion Bridge Company, builders of the bridge. He said an explosive charge could have caused marks of "heating" on one of the failures.

The Winnipeg Free Press, Manitoba, Canada, Thursday, September 13, 1951, Page 1.

Quebec Bridge Dynamited, Army Experts Charge

Is Claim

THREE RIVERS, Que., Sept. 13 (CP)--Two Canadian army engineering experts said today they believe strands of wire around a section of a steel girder of the Duplessis bridge were used to set off an explosion that caused its collapse.

Major-General H. Kennedy, federal government engineering consultant, and Brig. D. K. Black told a two-man commission investigating the collapse of the bridge last Jan. 31, that some "external force" was responsible for the tragedy. Four persons lost their lives while crossing the St. Maurice river span and another man was drowned when the tractor he was using to recover a submerged automobile crashed through the ice.

The army officers examined the debris of the $3,500,000 structure before testifying. Major-General Kennedy said he estimated that 25 pounds of high explosives were used to cause the collapse. Brigadier Black said he considered that 10 pounds of explosive would have been sufficient to crack the steel.

Both said that "no better place could have been chosen for the explosion" than where it was placed near pillor (sic.) No. 2 of the structure. This spot was readily accessible for such an act they said.


The Winnipeg Free Press, Manitoba, Canada, Tuesday, September 25, 1951, Page 1.

Bell Men Say Wires
For Phones, Not Blast

THREE RIVERS, Que., Sept. 25 (CP)--Two Bell Telephone company employees testified Monday that the "mysterious" wires found lying across debris of the Duplessis bridge were part of an emergency line set up following the bridge's collapse Jan. 31.

Witnesses earlier in the enquiry into the cause of the collapse indicated that the wires might have been used to set off an explosive charge.

The Winnipeg Free Press, Manitoba, Canada, Thursday, September 27, 1951, Page 40.

Bridge Inquiry Closes

THREE RIVERS, Que., Sept. 26 (CP)--Judge Rene Lippe declared the inquiry into the collapse of the Duplessis bridge closed at noon Wednesday. The inquiry opened Aug. 28.

Video news footage from British Pathé: