The story of one fall
2013-09-27 | Text: Lyudmila Smerkovich | Photo ©: | 5160

 

Engineering as a separate field of activity which emerged from bridge engineering, but there are large blanks in the history of its development. Among them is one of the most dramatic anthropogenic catastrophes befalling the American continent in the 20th century. This is the story of engineering blunders and administrative failures that led to two collapses of one and the same bridge in 1907 and 1916 in Quebec, Canada. Right after this tragedy a row of documents was produced, defining the destiny of engineering development.

 

Historical background

 

The necessity of a bridge construction over the Saint Lawrence River in Quebec had been under discussion since the middle of 19th century. It was quite evident that economic prosperity of the province was directly connected with trade routes; the river, however, turned on an annual basis from trade freeway to iced-up barrier as despite thick ice, the river was still considered too dangerous to cross. Moreover, the economically well-developed Quebec sought to play a special role in the Canadian economy and the transport problem complicated the realization of this wish. The situation particularly escalated when Montreal, during the five years, 1854-1859, built the Victoria Jubilee Bridge, connecting the city with the western ports. Such development quickly supported the status of Montreal as the main Eastern port of Canada. Quebec was left far behind in this competition; the province started loosing investment attractiveness.

The project of constructing a bridge over the river close to Quebec had been discussed for almost 50 years; this problem became at the focus of attention at every election, on the federal level as well as on local one. The messenger of the close arrival of elections had always been a few survey parties, appearing in the fields and making a plan for the future bridge location. Despite the importance of the situation, it had always ended up in plain talking – the task seemed to be too complicated both from the financial and engineering points of view. There was no possibility to realize the project till 1887, when several groups of business and political leaders formed a committee for the constructing the Quebec Bridge. Because of the high interest to the project, the Quebec parliament included the committee for the Quebec Bridge constructing company with the capital of one million dollar and the right to issue bonds.

The company immediately faced the problem of financing the grandiose bridge. State finance was offered. The money, however, could not be afforded until the place for the bridge was chosen. Thanks to essential financial help from the local legislatives of Quebec, preliminary surveys were completed. In 1898, after a few more years of discussion, a place called Chaudière was chosen out of three possible places to construct a bridge.

But financial twists went on for quite a long time. In 1889 the federal government afforded subsidies of one million dollars; one third of the money was for construction of the pillars and two thirds for the bridge superstructure. Quebec-City provided three hundred thousand dollars, the province of Quebec put in two hundred and fifty thousand dollars. All this money, along with two hundred thousand dollars gained by subscription, made one million seven hundred and fifty thousand dollars; the sale of bonds for the rest was expected to fund final construction of the bridge without terminal holdups, this sum was estimated at 4 million dollars. But even preliminary estimations showed that this huge money was not enough to build the whole bridge.

 

Projects and budgets

 

At the first the bridge construction project in Quebec seemed to be highly attractive for all interested parties – it was about a construction of state importance, huge budgets, and not to mention it was a challenge for the engineers of that time. The bridge was going to be one of the longest in the world and a particularly new experience for the American continent. So the ambition to get into the project at all costs was quite evident. Thus, the Pennsylvanian Company “Phoenix” offered to develop the bridge project for free, in exchange the Quebec bridge-constructing company was to grant “Phoenix” a contract for construction. Theodore Cooper, a famous American bridge constructor and the authour of many modern engineering ideas, personally offered his services to the Quebec bridge-constructing company.

But in fact it turned out that everything was much more complicated than it had seemed in the beginning. The money for construction was limited, the main advantage of the project was supposed to be its low price; the Quebecois could not even afford to pay in full for the services of the famous engineer. But the head engineer of the Quebec bridge-constructing company, Edward Hoare, had never dealt with bridges longer than 90 meters, so the project urgently needed an expert. Eventually it was agreed that Cooper, for a decent fee would still supervise the construction, but only from his office in New York – ill health stopping him from travelling as he was well over sixty at the time.

On the 6th of September 1898 a bidding system was announced, one could apply for a contract op to the 1st of March 1899. Technical conditions demanded a cantilever construction. There were six applications for bridge superstructures and two applications for substructures. Having examined all of them, Theodore Cooper announced: “Herewith I make a decision and inform, that the best and the cheapest project of cantilever construction of all given to me for examining and reporting belongs to the “Phoenix” company. The bid results were considered to be fair and open, we should mention, however, that the Quebec bridge constructing company was interested in the success of “Phoenix”.

Two months later the company gave a contract for building bridge superstructures to “Phoenix”, and for substructures – to “Devis”. “Phoenix” first refused to sign the contract with the Quebec bridge-constructing company because of the lack of financial support that set the whole project at risk. Financial problems had been solved only by 1903, when due to the support of Theodore Cooper and some Canadian politicians; they succeeded in enlarging the budget from the governmental side.

In the fall of 1903 the Canadian government at last resolved to build the “Grand Trunk Pacific” terminal and guaranteed its bonds as well as the bonds of the Quebec bridge-constructing company for US$6,678,000, but only after the shareholders purchased an additional 300 thousand dollars by subscription. This money was not only for the bridge construction itself, but also for highly expensive terminal blocks which would connect the bridge with the city and existing railways. After this, the delivery of materials for superstructures was immediately discussed, along with speeding up the project, but the installation of steel structures was not started until the spring of 1905.

We should still bear in mind that the main criterion for the project chosen was its low price.

Further on, Theodore Cooper would amend the project several times to make it cheaper, including his suggestion to lengthen the central bridge span. Because of this amendment the whole project was supposed to be recalculated and the model tests, assumed for unit constructions at that time, should have been undertaken. But the project was running out of time and considering the governmental bonds issue the project team did not approve recalculation. It was high time the construction work had begun and postponing could deter the investors and create difficulties with the governmental financing.

 

The twists and turns of construction

 

Officially the construction began on the 2nd of October 1900 after a solemn ceremony. Because of the extraordinary size of the construction the company had to apply innovative construction methods, which essentially prolonged the process. Some parts of the superstructure were not started until the 22nd July 1905. The “Phoenix” company promised to complete the building by the last day of 1908. Otherwise the company had to pay monthly 5000 dollars to the Quebec bridge-constructing company until the project was finished.

While building, the workers and supervisors discovered an essential deformation of some cables. When the workers tried to secure the matching of these cables, the holes made beforehand did not match. Moreover there were deflections in some of the most heavily laden elements working in compression. These deflections grew in time. Cooper was informed of this and he requested the reasons for the deformations, but no one could give him a satisfying answer. It was suggested that construction elements were delivered to the construction place already deformed at the plant – this was the opinion of the head engineer of “Phoenix”, P.Szlapka. He would admit later on, that in fact he had never seen the cables himself. And the producers guaranteed that all the elements had been perfectly straight when they had left the warehouse.

Some of the engineers did not pay much attention to the problem, as they considered it not to be dangerous. Others insisted that deflections resulted from defective calculations. The official representative of Cooper at the construction site was a young engineer, Norman McClure. On the 27th of August 1907, when the deflection of some elements reached the 57 mm mark, McClure managed to temporarily halt construction and went to New York to have a discussion with the general consultant. By that time the workers were afraid themselves to go to the bridge, there were several conflicts with the supervisor which ended up in a small strike. Nevertheless, while McClure was away they decided to proceed with the works.The explanation for this decision is to be found in a message, sent to Cooper by Hoare, where he wrote, that “moral consequencies of work withholding may be very nasty for all interested parties and may as well stop the works in this season because of the loss of working power”.

Theodore Cooper was seriously worried about what Norman reported to him. After a short conversation the engineers telegraphed the project team to stop all the works on the bridge immediately until the reasons for the deformations were revealed. Cooper asked McClure to send the same telegram directly to the construction site just in case, but Norman was late for his train and in the hurry he forgot to do so. When he reached Phoenixville, where the headquarters of the contractors was situated, he found out that his telegram had been completely ignored as the head engineer was not in the office, but they decided to hold a meeting to discuss the withholding of the work. Right during this meeting the bridge collapsed.

 

Collapse

 

The catastrophe of the 29th of August 1907, near Chaudière, shocked the society with ruthless consequences. It was not just a bridge-constructing failure, but a tragedy, which had taken the lives of 75 people. The collapse happened in the evening, 23 minutes to six. The workers had just finished the daily shift and were about to leave, but the majority stayed on the incomplete part of the bridge. The incomplete semi-arch was hanging more than 50 meters above the water, then all of a sudden it lurched and in 15 seconds collapsed into the river making a horrific wallop and shattering – the citizens of the nearby villages almost ten kilometers away from the bridge rushed out of their houses as they thought it was an earthquake.

The efforts to save the survivors did not succeed – it was getting dark, seriously injured people were stuck among the tangled crumpled balks, some drowned in the cold water. Moreover no one could understand what had happened and what was to be done, they were deeply shocked. A few people happened to survive by chance; they were taken to the boats, hoisted out immediately after the crash. Fortunately some of the victims were only slightly injured.

In the morning the bridge represented an awful scene – all the metal constructions above the water was tangled in a surreal fashion, 19 thousand tons of metal blocked the river, so that the traffic limitations were caused further problems. Than the full lists of workers on the bridge were compiled and victim identifications started. 61 people were announced unaccounted for, though it was obvious that most probably no one had survived. This was true, the corpses were found downstream during the following few days as well as among the wreckage of the bridge. The process of taking out the bodies was another complicated task – the victims had been trapped under heavy constructions on the bottom, or were stuck in the deformed baulks and cables.

33 of the lost and two of the injured were Indians who came from the nearby villages – they had worked on the bridge as high riggers. It turned out, that six of the Indians were safe, as in the morning they had argued with the supervisor and resigned. Several employees of “Phoenix” were lost. Among them were B. A. Yansell, a head supervisor, Mr. Berk, an engineer who came to the bridge minutes before its collapse, and two masters, John Worly and Jim Aidaho. One of the initiators of the cosntruction, executive manager of the Quebec bridge-constructing company, Mr. Barthe brought a company of his friends to the bridge right on that day to show off the bridge – they left the construction site an hour before the collapse and heard the crash from the road. Coming back to find out what had happened, they realized they had escaped death, as they had been walking across the bridge just before the catastrophy.

The newspapers of the whole world offered sympathies to Canada, London wrote about the bridge crash in Quebec as of “a tragedy shared by the whole empire”. Canadian press described all the details of the catastrophy, so even today we can find out all the horrors and miracles that happened on that evening in Quebec.

 

Investigation and aftermath

 

S.N.Parent, the chairman of the National Transcontinental Railway Company, declared, that the “Phoenix” company, which held the contract for metal constructions, were working too swiftly, and while pushing a heavy car with steel elements that was on the bridge at the moment of its collapse, some of the necessary cleats were not fastened properly and probably this fact led to the bridge’s collapse.

The true reason for the collapse was determined by a Royal committee formed by the Governor General of Canada, which consisted of three civil engineers. They prepared a report that became a benchmark in the engineer-technician discipline; it contained more than 200 pages, including 21 appendicies. William D. Middleton writes that the accuracy and objectiveness of their investigation and report have become today a certain standard. The investigation of the Quebec bridge collapse influenced the standards of engineering on the American continent, despite the fact, that the catastrophy happened 15 years before any regulatory authorities and technical law were formed.

But let’s return to the results of the investigation. The direct reason for the collapse was the deflection of the lower cables in the anchor arm close to the backbone of the bridge; the report however analyzed the suppositions of this fact more thoroughly. Below are some of the main conclusions (ps. 9-10, Holgate and co, 1908):

A serious mistake was that too little mass of the whole construction was included in the calculations and this fact was not double checked. This mistake was enough to declare the bridge inacceptable, even provided that the elements of lower cables were solid enough; if the bridge were mounted according to the project, the true stresses would be much higher than those accepted by technical conditions. This mistake was made by Mr. Szlapka and confirmed by Mr. Cooper, accelerated the catastrophe.

It was a mistake that the Quebec bridge-constructing company did not hire an experienced and qualified person as a head engineer, for this reason the control over all types of works from the Quebec bridge-constructing company and the railway company was not thorough and full.

The modern professional knowledge about steel columns under pressure is not sufficient to let engineers save money on such projects as the Quebec Bridge. You could build a bridge with the span chosen which would be safe of course, but possessing the knowledge of modern methods, one should use much more metal than necessary in case our knowledge was more precise.

The final result of the committee was: The collapse cannot be directly explained through any other reason than a mistake from the side of these engineers. Such estimation mistakes can not be explained through the lack of general professional knowledge, nor through negligence or desire to save money.

The main responsibility for the collapse was imposed on the engineers Theodore Cooper and Peter Szlapka. Though Szlapka continued working as a head designer for the “Phoenix” company. Cooper opted for a private life and resigned. By some quirk of fate he died just two days after the Prince of Wales officially opened the newly completed Quebec Bridge.

 
 
Planned characteristics of the bridge
 
The width of the Saint Lawrence River at its narrowest station was about 3.2 km. In the middle it was 58 meters deep. The speed could reach 14 km/hour and the tides were about 5 meters. During the winter the ice in the narrow part of the river and its height was up to 15 meters.
The bridge would have crossed the Saint Lawrence River almost 14 km to the North from Quebec, connecting it with the main railway. The distance between the cantilevers was 171.5 meters. They should have held the suspended span of 205.7 meters. It should have been 45.7 m above the water. Initially the designed length of the free span was 487.7 m.
But in May 1900 Theodore Cooper increased the length of this span to 548.6 m. He noted, this would help to overcome the uncertainty about building the pillars in such deep water, to decrease the ice influence and to shorten the time of construction. Despite these essential technical reasons for such an amendment, it is also true that the increasing of the span would have made Cooper the engineer of the longest cantilever bridge in the world (Petroski, 1995, p. 46; Middleton, 2001).
 
 
The second bridge
 
After the collapse the government took the responsibility for project developing and constructing a new bridge. It also provided financial help. The second bridge was much heavier than the first one. Petrocki (1995) compares the sizes of two bridges, demonstrating an essential increase in the sizes:
The cross-section square of critical compression member of the old bridge was 543 000 mm2 (842 inches2), one of the new bridge – 1 250 000 mm2 (+1941 inches2) (Petroski, 1995, p. 113; Middletone, 2001, p. 116).
The second attempt to construct a bridge over the Saint Lawrence River was problematic as well. The project failed once again in 1916, when the cast element of the crane could not withstand the pressure and the central span crashed into the water.
Thirteen workers were lost in this catastrophy. The 50m (500 tons) span sank to the bottom of the river to rest near the ruins of the first bridge, which are still there today. The second bridge was finally completed in 1917 and its weight was twice as much as of the first one. (Tarkov, 1986).

 

 
 
“Manitoba Free Press”, 30.08.1907:
 
The one certain fact is that at a place where this afternoon there was almost half of a bridge that was to become one of the engineering wonders of the world, with a small army of mechanics and workmen, there is nothing now but a mass of fantastically twister iron and steel wreckage, and a terrible number of corpses floating down the river, or crushed in between the fallen girders. The bodies rescued so far are in a terrible state, crushed and broken until they can scarcely be recognized.
The horror of the situation is increased by the fact that there are a number of wounded men pinned in the wreckage near the shore. Their groans and shrieks can be plainly heard by the anxious crowds who are waiting at the water's edge, but nothing so far can be done to rescue them or relieve their sufferings in the slightest degree. There are no search lights available and by the feeble light of lanterns it is impossible to even locate the sufferers, so that for the present nothing can be done but leave them to their fate”.
 
 
“Manitoba Free Press”, 30.08.1907:
 
Work was going on and as usual, the men being employed in placing the immense girders in position. In this work a track had been laid on the bridge and an engine with freight cars and several heavy moving cranes were employed in getting the steel into position. The engine was seen to start out for the end of the bridge with a load of steel. 
As it approached to the end, the first premonition of disaster was felt by the engine driver who felt his engine jerk. He shut off the steam at once, but the engine continued to move. The outward end of the structure sagged a little and a moment later collapsed.
This much has been gathered from the engineer, who has by marvelous chance escaped the general destruction. He fell with his engine as the bridge gave way, but is not able to say how he escaped. He was picked up later by a boat and became unconscious, and when he recovered his senses knew little beyond the fact that he felt the bridge go and knew he was falling. When he returned to consciousness he was on shore. The rest of his crew was still in the river.
 
 
“Manitoba Free Press”, 30.08.1907:
 
The awful completeness of the catastrophe seems to have paralyzed the sensibilities of everybody near the place. There is scarcely a family in the village of St. Romauld and New Liverpool which has not been bereaved, while in some cases five and six men of a single family have been killed. Driving through the village, the sounds of lamentations of women can be heard from almost every house. Most of the men are gathered around the approaches to the place where the bridge was, some aiding in the efforts to rescue those who are still alive, and others waiting around for news, or helping to dispose the bodies of the dead as they are found. The disaster has produced an extraordinary effect in this city and is regarded as a national calamity.
 
 
“Manitoba Free Press”, 31.08.1907:
 
The steamer Glenmount, Captain Muir, en route from Montreal to Sydney, was close to the bridge when it collapsed. Pilot David Perreault, who was piloting the steamer, said the vessel had just passed the bridge when there was a tremendous report. Then there was a great upheaval of the water in the river, some of it breaking over the stern of the vessel. For about ten minutes it was impossible to see anything in the direction of the bridge, owing to the spray and clouds of dust from the fallen structure. 
When Captain Muir saw what had occurred he ordered the steamer to be put about and went over as near as possible to the bridge piers. He then lowered his boats in the hope of picking up some of the unfortunate men who were carried down by the structure. Although the boats cruised around for some time, they did not pick anybody up. Perreault said the noise made by the falling bridge was really awe-inspiring.
 
 
“Manitoba Free Press”, 04.09.1907:
 
At the opening of the inquest to-day, Engineer Hoare was questioned on the report. In reply to the coroner, Mr. Hoare said that he never thought the condition of that chord was serious enough to cause an accident to the bridge, but for the reason previously stated he thought it was of sufficient importance to necessitate McClure himself going to New York. The witness stated that since the accident he had not had time to make a thorough examination of the bridge, nor enough to come to a definite conclusion. 
Mr. Hoare stated that a very precise inspection was made of the work. It progressed not only at the bridge where the construction was going on, but in Phoenixville as well where the material was prepared. They had noticed a deflection in other pieces of steel, but not so pronounced as this one, but never considered them of any moment as they always could be repaired. Asked by the coroner, he said that it might have happened in transportation. He could not say as to whether it had happened before or after the chord was put in place, but if before it was probable that it would have been noticed. It may have been damaged before it went into the bridge and it may have happened after, and until a thorough examination could be made he would not give an opinion.
This concluded Mr. Hoare's evidence, and the next witness called was Mr. Norman McClure, the engineer who went to New York to consult Mr. Cooper. Mr. McClure said that Mr. Cooper did not make any recommendations or offer any suggestion to him at all, and did not tell him that they should not put any more load on the bridge. He did not give the witness any instructions to telegraph to Quebec.
 

Illustration from the book «The Quebec Bridge», 1918; photo from the Vancouver archive / Major J.S. Matthews: www.searcharchives.vancouver.ca; photo from the archive "Library and archive of Canada": www.collectionscanada.gc.ca.

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