Quebec City’s Cantilever Bridge
par L'Hébreux, Michel
The Pont de Québec [Bridge] has left its mark on the history of transportation and engineering in Canada. It is the world's longest cantilever bridge, with 549 metres of clear span between its main pillars; it exceeds the Firth of Forth Bridge near Edinburgh, Scotland, by 28 metres. At the beginning of the 20th century, the promoters of the Quebec Bridge project described the endeavour as the future eighth wonder of the world, particularly because its construction represented such a colossal challenge for the era. In fact, this feat of civil engineering was accomplished with great difficulty, and that, only after decades of expectation and two unsuccessful attempts that caused the death of 89 workers. The Quebec Bridge was, at last, successfully completed on September 20th, 1917, as over 125,000 spectators watched enthusiastically. Today it is considered as a world-class engineering masterpiece and has been designated as an International Historic Civil Engineering Landmark and a National Historic Site of Canada.
On October 2nd, 1900, during a grandiose ceremony, Sir Wilfrid Laurier, then Prime Minister of Canada, laid the first stone for the northern pillar of the Quebec Bridge. Accompanied by Simon-Napoléon Parent, mayor of Quebec City and president of the Quebec Bridge & Railway Co. that would be helping with the bridge project; Laurier launched the construction project, which would be supervised by the Phoenix Bridge Co. of Phoenixville, Pennsylvania.
During the building of the superstructure, which was started in the summer of 1905, problems multiplied quickly. Workers found it difficult to align the various component parts and realized that a number of sections were bending. These troubling difficulties raised certain concerns, but Theodore Cooper, the chief engineer, who was supervising the construction from his New York City office, remained reassuring. Since Cooper was widely trusted and considered an expert, the young, inexperienced engineer whom the American had entrusted to monitor the work forged on ahead. However, on August 29th, 1907, while about 100 workers were busy erecting the iron structure, with only 20 or so minutes left in their shift, a catastrophe occurred. A terrible noise that could be heard many kilometres away filled the air and the entire southern segment of the bridge, all 391 metres of it collapsed onto the shore and into the river, causing the death of 76 people.
In the months that followed, a commission of inquiry would establish that the collapse of the bridge was due to fundamental errors in the blueprint design, combined with a lack of judgment on the part of Theodore Cooper. Cooper had modified the original blueprints by increasing the distance between the main pillars from 488 to 549 metres without revising his other calculations. The pretext he gave was that he wanted to facilitate construction of the pillars and protect them from ice during the winter, but his main objective may well have been to make the Quebec Bridge the world's longest cantilever bridge, without taking the necessary precautions.
In 1908, the Canadian government took over reconstruction of the bridge, since the structure constituted an essential link between Quebec City and the Transcontinental Railway which, in those days, still passed through Lévis on the other side of the St. Lawrence River. The government appointed a committee made up of three engineers and told them to draw up new specifications. After a dispute which led to the resignation of the committee chairman, responsibility for constructing the bridge was left in the hands of the St. Lawrence Bridge Co., the product of a consortium involving the Dominion Bridge Co. of Lachine, Quebec and the Canadian Bridge Co. of Walkerville, Ontario.
Blueprints were prepared by the St. Lawrence Bridge Co. under the supervision of the engineering committee. Extremely strict norms were followed in order to ensure that no error would find its way into the project this time. For instance, in the new plans, the figure specifying the required quantity of steel was nearly the double of that of the first bridge. Although the construction plan remained the same-specifying a 987-meter-long cantilever bridge with a 195-metre suspension span-the president of St. Lawrence Bridge, Phelps Johnson, improved on the original design by creating a new system known as the K-truss bracing system, a truss geometry resulting in a more effective, elegant structure, easier to build than the bridge in the blueprint proposed by the engineering committee.
The anchorage arm and the north-south cantilever were built between 1913 and 1916. Then, on September 11th, 1916, the time came to raise the central span that had been constructed in Sillery Cove, which was intended to join the two cantilever arms and finish the building of the bridge. Over 100,000 people gathered in Quebec City to celebrate the big day. However, during the raising of the 5,000-ton span, a dreadful cracking sound was suddenly heard and the span began to twist and sag and then it sunk into the depths of the river with a terrible crash. Thirteen people lost their lives and fourteen more were wounded in this second tragedy, which was attributed to the defective casting of a cruciform support of the central span.
These two tragedies would remain etched in shared memory of the community, as events that were almost as great as, if not greater than the feat of engineering that it took to build the bridge.
Finally, the following year, on September 20th, 1917, before an immense crowd estimated at 125,000 people that had come from all four corners of Canada and the United States, the central span was erected without a hitch. Quebec City was decked out in all its finery for the occasion and a number of demonstrations of joy erupted throughout the town, as workers, engineers and the general population celebrated the successful completion of this great marvel of civil engineering.
At this point, the dream that Quebec City had kept alive for so many years finally came true and the city became a national-level transportation crossroads. As of 1917, the bridge put Quebec City and its region into direct contact with the south shore of the St. Lawrence River and the United States, a link that brought the city 11 railway companies whose lines up until that time had only run along the south banks of the river. The new bridge advantageous in that it shortened the rail distances between Quebec City and Halifax, as well as Winnipeg, by several hundred kilometres.
In addition, as of 1929, a 4.27-metre-wide motor lane was added to the two rail lines running on the bridge. This new addition made it possible for cars to cross the bridge as well. Until 1949, flaggers directed traffic on the bridge and collectors gathered money from the drivers. Then as cars and trucks gradually began to crowd out railways, in keeping with the prevailing trend, the government ordered the motor lane to be expanded and removed one of the rail lines. Quebec's premier, Maurice Duplessis, officially opened this renovated version of the Quebec Bridge on May 25th, 1952.
During the time of its construction, the Quebec Bridge enjoyed significant international fame and influence. Highly renowned foreign engineers, such as Eiffel, Brownlee, Serrell, Cooper, and several others took an interest in the bridge or played various roles in its construction. It should also be pointed out that, in 1916, at the time of the first attempt to raise the central span; Japan delegated 200 engineers to attend this world première. For the occasion, over 100,000 people from all over Canada and even from the United States also assembled on both shores of the St. Lawrence River in order to be eye witnesses to this feat of engineering. Newspapers reported that never before had such a crowd been seen in Quebec City and that the hotels could not accommodate the visitors who, and so most of spent the night camping in the open air. In 1917, 125,000 people looked on as the central span of the Quebec Bridge was successfully erected.
The Quebec Bridge is still mentioned today in international engineering publications as the best illustration of the cantilever bridge technique, and of course, as the longest bridge of its kind in the world. This influence and renown is due to the courage and tenacity of the Quebecois who saw this great project to its completion, in spite of all the obstacles that arose along the way.
The wholesale involvement of various politicians at the beginning of the 20th century made it possible to complete the bridge that, for 50 years, Quebecois had been waiting for. At the time it was a structure that was being called the grand public work of the Confederation. It was a sign of the times and of the international importance of this feat that the Prince of Wales (the future Edward VIII, King of England) came to officially open the Quebec Bridge in 1919.
The bridge provided Quebec City and the surround area with a direct link to the south banks of the St. Lawrence River, as well as to the United States. Earlier, during the mid-19th century, the railroad had brought great prosperity to Lévis, where the Grand Trunk Railway Company had pushed for the construction of reception facilities for immigrants, as well as a number of hotels to accommodate travellers in transit. Railroad-related activities required a large workforce, and so, the population of Lévis considerably increased. Momentum shifted with the building of the Quebec Bridge, and as a consequence, the arrival of transcontinental railway companies greatly boosted the development of Quebec City, which, in addition to being the provincial capital, it had a larger population than Lévis.
Classed as a masterpiece of civil engineering at the time of its successful completion, the Quebec Bridge has continued to be awarded recognition.(NOTE 1) In 1987, it was designated an International Historic Civil Engineering Landmark by the American Society of Civil Engineers and by the Canadian Society for Civil Engineering. Only four works of civil engineering have ever received such an honour throughout the entire world. At the end of January 1996, it was the Canadian government's turn to honour the Quebec Bridge by declaring it a National Historic Site, thus recognizing it as the most important work in the history of Canadian civil engineering.
To a certain extent, the Quebec Bridge is to Quebec City what the Eiffel Tower is to Paris or the Statue of Liberty to New York City, even though the bridge's status as a tourist attraction is hardly comparable. The three structures have acquired a symbolic value for the local populations, whose sense of identity is tied to these landmarks.(NOTE 2)
In October 2001, an architectural lighting project designed to cause the bridge's colour to vary according to the rhythm of the St. Lawrence River's tides was completed. Unfortunately, the finished product was considered a disappointment given the unimpressive lighting effects and the high expectations that the project had raised. Its designers hope to have the opportunity to improve their lighting system, so as to better showcase this masterpiece of engineering.
Over the last 20 years, the Quebec Bridge has been having serious corrosion problems. In 1987, the Coalition pour la Sauvegarde et la Mise en Valeur du Pont de Québec [Coalition for safeguarding and Maintaining the Quebec Bridge] was created. And so, after several years efforts, the group managed to convince the three main entities responsible for the bridge's maintenance (the governments of Canada and Quebec and the Canadian National Railway Company) to sign two successive restoration agreements. In 1993, the Canadian government sold the Quebec Bridge and various railway right-of-way corridors situated throughout the country to a then crown corporation now known as Canadian National for the nominal fee of $1. In return, the company promised to completely restore the bridge. However, in 1995, the federal government privatized Canadian National, and as a consequence, a new 10-year tripartite agreement had to be renegotiated. Unfortunately, when the agreement lapsed in 2005, only 40 percent of the bridge had been repainted and made rust free. As it happened, Canadian National refused to invest any more money in bridge renovations, and so, work was interrupted. Faced with the deadlock that ensued in spite of intense negotiations, in 2007, the Canadian government vowed to initiate legal proceedings against Canadian National, in order to force the company to finish the repair work that it had begun on the Quebec Bridge.
This conflict reflects a profound difference of opinion concerning the heritage value of the Quebec Bridge. On the one hand, a private company having taken over ownership of a very valuable community facility refuses to invest a penny more to restore the splendour of yesteryear and to guarantee that the work will last for years to come. On the other hand, a coalition of individuals and organizations is pressuring the company (as are the governments in Ottawa and Quebec City) to protect and enhance this masterpiece of civil engineering, so that future generations can also benefit from this unique heritage.
It can only be hoped that this latest episode in the stormy history of the Quebec Bridge will end happily. Particularly because the bridge has the potential to once again become a large-scale attraction to be treasured by the regional tourist industry-provided that it is protected and enhanced as it should be.
Author and conference speaker
Note 1: This is a good place to mention that the Seven Wonders of the World were designated during ancient times by a Greek named Philo of Byzantium who did so about three centuries before the birth of Jesus Christ. Of the seven wonders identified at that time, only the pyramids of Egypt have lasted to this day. The Quebec Bridge has therefore never been officially categorized as a Wonder of the World.
Note 2: It should be pointed out that including its approach spans the Quebec Bridge is the equivalent in length to three times the height of the Eiffel Tower and that it weighs nearly nine and a half times more than the French landmark. In Canada, the Jacques Cartier Bridge, completed in 1929, ranks 13th among all cantilever bridges with its 334.37-metre main span.
L'Hébreux, Michel, Le pont de Québec, Sillery, Éditions Septentrion, 2001, 255 p.
L'Hébreux, Michel, Ce sera le plus grand pont du monde, Montréal, Éditions Les 400 coups, 2005, 32 p.
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Élévation de la travé
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L'Installation de la
Pont de Québec – Cons
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Pont de Québec – Cons
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- Extrait d'un article rapportant le désastre de 1916
- Extrait d'un article rapportant les détails au lendemain de la catastrophe
- Extrait d'un article rapportant les détails au lendemain de la catastrophe
- Extrait du témoignage d'un observateur du désastre de 1916