The panel’s report found that the main cause of the bridge’s failure was improper design of the latticing on the compression chords. They were found to be as much as 10 percent in excess of those previously calculated (p. 65, Middleton, 2001). Sep 9, 2017 Can ego knock a bridge down? The devastating collapse of the Québec bridge in 1907 was followed quickly by a decision of the federal government that the project must proceed. Its waters were about 58 m (190 ft) deep at its middle. Over time, some of the member deflections increased. In the calamity, which occurred on 29 August 1907, 74 of the 85 men working on the bridge at the time lost their lives. �Erection of the Main Vertical Posts of Quebec Bridge�, (1907), Engineering Record, Vol. Being dissatisfied with the theories offered by the engineers on site, Cooper developed his own theory. Royal Commission Quebec Bridge Inquiry Report. It was at time of construction the longest cantilever bridge in the world with clear span of 1800 ft. Cooper met with Schreiber personally. This confirmed the commission�s findings that the chords were inadequately designed. �, �The loss of life on August 29, 1907, might have been prevented by the exercise of better judgement on the part of those in responsible charge of the work for the Quebec Bridge and Railway Company and for the Phoenix Bridge Company.�, �The failure on the part of the Quebec Bridge and Railway Company to appoint an experienced bridge engineer to the position of chief engineer was a mistake. His decisions were not questioned, even when they seemed to be unusual. The stress calculations were based on the 487.7 m (1,600 ft) span dimension. history was the collapse during construction of the bridge over the St Lawrence near Quebec City (see Figure 1). The manufacturer guaranteed that all the members had been perfectly straight when they left the yard. A cantilever bridge was proposed as the most feasible design to bridge the harsh, icy waters of the St. Lawrence River. On October 2, 1900, the Prime Minister of Canada, Sir Wilfrid Laurier, placed the cornerstone of the Quebec Bridge. The Collapse of the Quebec Bridge- A Mistake Made Twice Facts The Quebec Bridge was The top chords for the anchor and cantilever arms in the Quebec Bridge were slightly curved, for aesthetic reasons. The Quebec Bridge was the longest cantilever structure attempted until that time. The first collapse in 1907. and Theodore Cooper, the most reputed engineer of that time became the main consulting Only eleven workers on the span survived. Petroski, Henry (1995). per foot) until they reached the dimensions of 9.1 m (30 ft.) by 40.5 m (133 ft) at the top. After a few meeting his design was approved with very few changes by Cooper. The stresses that caused the failure were not due to abnormal weather conditions or accident, but were such as might be expected in the regular course of erection. The Quebec Bridge was the longest cantilever structure attempted until that time. Quebec Bridge Collapse - A Case Study 1. The failure of these chords was due to their defective design.” In 1898, after years of debate, the Chaudiere site was selected from the three recommended sites to be the location of the Quebec Bridge. All concerns were directed towards him, even though, due to illness, he was unable to travel to the job site. The bridge initially collapsed on August 29, 1907. Engineering Record (ER). First Collapse in 1907: The collapse of the Quebec Bridge resulted from the failure of the lower chords in the anchor arm near the main pier. However, the project did not gather momentum until 1887, when a group of businessmen and political leaders came together and formed the Quebec Bridge Committee. In its final design, the clear span was 548.6 m (1,800 ft) long. Most of the poor engineering decisions were made by the prominent consulting engineer, Theodore Cooper. The top 5.8 m (19 ft.) of each pier was made of solid granite. At around 3:00 p.m. Phoenixville�s chief engineer returned to his office. (1907b). A bridge of the adopted span that will unquestionably be safe can be built, but in the present state of professional knowledge a considerably larger amount of metal would have to be used than might be required if our knowledge were more exact.�. The cantilever arms would reach a distance of 171.5 m (562.5 ft.). However, it also suffered a partial collapse when the middle span fell into the river. His consulting services were based on the information that was reported to him by others in charge. The rail bridge was designed to link the two shores and provide easier transit for the 11 railroad companies in particular between the railways in Québec and the United States. Whenever the need arose, the authorities on site would confer with each other before making any decision. Bridge specifications were improved after this collapse (Shepherd and Frost, 1995). When skilled ironworkers observed the growing deflections, indicating a gradual collapse of the structure, a confident site supervisor might have realized the gravity of the situation and halted construction. Deflections were first noticed as early as mid-June, and were reported to Cooper by his on-site inspector, Norman McLure. 29 � 30, Middleton, 2001). One of the construction foremen decided to halt work on the bridge until matters could be resolved. However, the Phoenix Bridge Company refused to sign a contract with the Quebec Bridge Company due to the financial provisions, which left the bridge company open to considerable risk. In return, the Quebec Bridge Company would then be obligated to give the tender for construction of the bridge to the Phoenix Bridge Company. American Society of Civil Engineers, New York, New York. With some financial help from the local Quebec legislature, preliminary surveys were made. The Quebec Bridge (Pont de Québec in French) is a road, rail and pedestrian bridge across the lower Saint Lawrence River between Sainte-Foy (since 2002 a western suburb of Quebec City) and Lévis, Quebec, Canada.The project failed twice, at the cost of 88 lives, and took over 30 years to complete. In a properly computed bridge the assumed dead load concentrations upon which the make-up of the members is based should agree closely with the weight computed from the dimensions in the finished design and with actual weights� (Holgate et al., 1908). The Royal Commission Report, which investigated the collapse and identified the engineering and procedural errors that had lead to it, remains a pioneering document in the field of forensic engineering. In Schneider�s opinion, �These members consist of four separate ribs, not particularly well developed as compression members, and their connections to each other are not of sufficient strength to make them act as a unit� (p. 97, Middleton, 2001). William Middleton gives a clear definition of a cantilever bridge in his book: �Cantilever bridge: a bridge form based upon the cantilever principal. Others were still insisting that the bends were the result of a pre-existing condition. A second attempt to bridge the St. Lawrence River was made. The specifications called for a cantilever structure. Some of the major chords with their corresponding deflections, with the dates of measurement, are presented in table 2. This resulted in a loose and inefficient supervision of all parts of the work on the part of the Quebec Bridge and Railway Company.�, �The work done by the Phoenix Bridge Company in making the detail drawings and in planning and carrying out the erection, and by the Phoenix Iron Company in fabricating the material was good, and the steel used was of good quality. The project suffered a second collapse in 1916, when a casting in the lifting apparatus broke, causing the center span to fall into the water. The initial design length clear span was 487.7 m (1,600 ft). They relayed a message back by telephone, saying that it was safe to resume work on the bridge. A cantilever bridge was proposed as the most feasible design to bridge the harsh, icy waters of the St. Lawrence River. Schneider wrote in his report, which was published as an appendix to the Royal Commission Report, �If a column is made up of several shapes or parts, they have to be connected in such a manner that they will act as a unit. In its typical form cantilever arms projecting toward the center of the span from main piers are continuous with and counterbalanced by anchor arms extending between the main piers and anchor pier at each end. According to Engineering Record, �As a rule secondary stresses are much more dangerous in tension that in compression members, which seem to have been the first to give way in the Quebec bridge� (ER, 1907e). The anchor pier towers would withstand a load of 34.8 MN (3,500 tons). The bridge project was financially troubled from the beginning. How one man's decisions caused the collapse of the Quebec Bridge. Once this error had been discovered and brought to Cooper�s attention, he immediately made an estimate of the new stresses that would occur. The members under the highest compressive loads were gradually buckling. The second bridge was finally completed in 1917 and weighed two and a half times as much as the first one (Tarkov, 1986). The Quebec Bridge was twenty years in the making, from the founding of the Quebec Bridge Company in 1887 to the bridge�s collapse in 1907. Request PDF | Collapse of the Quebec Bridge, 1907 | In the late 19th century, the transportation needs of Quebec led to proposals for bridging the St. Lawrence River. Cynthia Pearson. Cooper accepted these heavier loads and stresses, in addition to the already high stresses set for the bridge, as being within acceptable limits. The message from Cooper reached the Phoenixville office at 1:15 p.m. Earlier, noted French engineer Gustave Eiffel had considered the problem and found that a cantilever design would be superior to either a suspension or an arch bridge for the Quebec site (pp. The anchorage arm and the north-south cantilever were built between 1913 and 1916. McLure continued to argue that the bends in the members had occurred after they were installed. Cooper wired a message back referring to chords 7L and 8L, asking, �How did bend occur in both chords?� The chief engineer of the Phoenix Company replied to Cooper saying that he did not know (pp. Erection of the superstructure portion of the bridge did not begin until July 22, 1905. This provides at least an impression that the process was not fair and open, even though, (Holgate et al., 1908) concluded, �As to either party influencing Mr. Cooper or causing him to modify his ideas so as to favour any tender, such a suggestion is, in our opinion, quite out of the question, and we believe that Mr. Cooper made his decisions and gave his opinions with absolute honesty.� (p. 15, Holgate et al., 1908). The Quebec Bridge was the longest cantilever structure ever to be attempted during its day. 302. The Engineering Hevs commented 'The fall of this bridge ranks with the greatest engineering disasters in history. After review, Theodore Cooper stated, �I hereby conclude and report that the cantilever superstructure plan of the Phoenix Bridge Company is the �best and cheapest� plan and proposal submitted to me for examination and report.� (p. 15, Holgate et al., 1908, p. 34, Middleton, 2001). �A Disaster in the Making.� American Heritage of Invention and Technology, Spring 1986, 10-17. http://www.civeng.carleton.ca/Exhibits/Quebec_Bridge/intro.html, http://www.mysteriesofcanada.com/Quebec/quebec_bridge_collapse.htm, http://www.civ.toronto.edu/funstuff/disaster/quebec.htm, https://www.structurae.net/en/structures/data/str00479.php, https://helios.physics.uoguelph.ca/summer/scor/articles/scor213.htm, http://www.disastershq.com/features/quebec.asp, ASCE Technical Council on Forensic Engineering (TCFE), 9201 University City Blvd., Charlotte, NC 28223-0001, © 2013 UNC Charlotte | All Rights Reserved |, The University of North Carolina at Charlotte, Bridge superintendent of erection for 1st year of work, General foreman of erection for remainder of project. Schreiber recommended that the governmental agency of Railways and Canals hire a consultant on their behalf. Table 1. The wreckage is shown in figure 3. Over 100,000 people gathered in Quebec City to celebrate the big day. The cross sectional area of the critical compression member for the old bridge had been 543,000 mm2 (842 in.2), whereas that of the new bridge was 1,250,000 mm2 (1,941 in.2) (p. 113, Petroski, 1995, p. 116, Middleton, 2001). Associate Professor, Dept. Only eleven of the workers on the span were recovered alive, and some bodies were never found. Construction finally began in October 1900. A recent review of the history of the bridge and the two collapses was written by Middleton (2001). A rigid joint that transferred loads uniformly across its area to ensure only axial loading deflections ) were in., believing the collapse of the quebec bridge it was assumed that the bends in the design and construction water. 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