THE QUEBEC BRIDGE DISASTER

On the evening of August 29^th, 1907, a whistle blew signaling the end of the day shift on the construction of the Quebec Bridge over the St. Lawrence River. Suddenly, a loud sound like a cannon shot reverberated through the partially completed south cantilevered arm of the bridge. The bottom chords on the anchor arm failed, and the entire south tower, cantilever arm, and partially completed center span fell into the river, killing 75 workers. This disaster is known today for the authoritarian decisions that were made by the few top engineers, and the lack of authority given to the junior engineers under them in the lead up to the bridge collapse.

In the beginning stages of designing the Quebec Bridge, the Quebec Bridge Company was financially troubled and known for struggling to get projects accomplished. They hired a lead consulting engineer by the name of Theodore Cooper to oversee the design and construction of the Quebec Bridge to bring expertise to the company. Cooper was at the time one of the most respected bridge builders and was nearing the end of his life-long engineering career. He was very interested in taking over the Quebec Bridge project because he never was in charge of a truly historic masterwork and viewed this as his crowning achievement.

During the analysis of the preliminary plans for the bridge submitted by the Phoenix Bridge Company, Cooper said he had found “not a single vital or important criticism or mistake,” and felt that the plans proposed the “best and cheapest” design. A year later, Cooper recommended that the span of the bridge be lengthened from 1600 to 1800 feet in the interest of constructing the piers in shallower waters and out of the path of ice flows. This concept would save the Quebec Company time and money; however, would also introduce higher allowable stresses in the bottom chords near the piers. Lacking sufficient funds from the company to conduct any research or testing of the new span design, Cooper did not have the increased loads on the bridge recomputed and thus accepted the weights provided by the Phoenix Company. The only engineers that challenged Cooper’s decisions were put down, with him writing, “This puts me in the position of a subordinate, which I cannot accept.”

As work began on the bridge, and the shop drawings for the south anchor arm were completed, another chance to recompute the weights was passed over by Cooper. A few months later, Cooper received a letter from the Phoenix Company reporting that the actual weight of steel in the bridge had far exceeded the original estimated weight (from 62 to 73 million pounds). By this time, most of that section of the bridge had already been constructed; so rather than start all over Cooper decided that the increase in stresses were safe, and permitted work to continue.

Over the course of construction on the Quebec Bridge, Cooper’s health was deteriorating and he was unable to travel from his office in New York to the site in Quebec. Therefore, he hired a recently graduated engineer by the name of Norman McLure to essentially serve as Cooper’s “eyes and ears” on the project site. Since Cooper had virtually attained absolute authority and control in the engineering aspects of the bridge, there was no one on the site with enough experience to make effective decisions- all problems were communicated from McLure to Cooper through letters.

When the center span was being added to the south arm, the lower chords under the bridge deck started to show signs of buckling. This was brought to Cooper’s attention through McLure, in which Cooper replied, “Make as good work of it as you can, it is not serious…” As the span continued to extend outward, the buckling in the members worsened. John Deans, chief engineer for the Phoenix Bridge Company, claimed that the bottom chord members had shown some bending during manufacture and were considered by him to be “serviceable.” Construction continued and the increasing loads on these members caused even more buckling to occur; however, Deans still insisted that the bending occurred during manufacture, and that work could continue. No one on site was willing to override the judgment of the senior engineers until it was too late.

QUESTIONS

· Do you think it was intentional to place the financial interests over safety?

· Was Cooper’s ego unethical? If so, what ethical codes did he violate?

· Was Deans’ continued insistence that everything was acceptable unethical? If so, what codes did he violate?

· Should the Quebec Bridge Company have put the project out for bid based on marginal funding?

· Did the young engineer McLure act ethically in how he performed his duties?

· Was it ethical to place engineers on the job site that lacked the experience or the confidence to act decisively?