How Did The Tacoma Bridge Collapse?
Overall, it can be seen that the Tacoma bridge collapse occurred due to a number of crucial decisions made by engineers, contractors and the government. The extent to which these decisions were ethical depends on the ethical stance being considered. Economically, the government favoured reducing costs as opposed to the safety and quality of the bridge. Similarly, the contractors accepted the contract for a design that they were not able to fully complete and had to make changes when constructing the bridge. During the construction stage, Clark Eldridge did not abide by the engineering ethical principles as he failed to "identify, evaluate, mitigate and manage risks"8 arising from the oscillating deck. Leon Moisseiff's keenness on applying
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the new Austrian aerodynamic principle (that was not tested experimentally before) in practice meant that the public's safety was at minor risk. Hence, the previous decisions can be deemed unethical and their outcomes suggest that Eldridge, Moisseiff, the government and the contractors are all partially responsible for Tacoma's collapse. In contrast, Farquharson is not responsible for the collapse of the bridge as he acts in an ethically responsible manner, attempting to find a solution for the oscillations. To conclude, engineering failures are often associated with a deficiency in engineering ethics and to minimise these failures, professional engineers must prioritise moral standards and aim to follow the set ethical principles when making their decisions.
Engineering Ethics: The Tacoma Narrows Bridge Collapse
Engineering is a very important discipline that integrates into our daily lives. Engineers significantly contribute to the development of societies and always face the challenges of innovating and designing the most viable solutions for the future. Many great accomplishments have been achieved in the various fields of engineering such as the construction of towers and bridges as well as the development of artificial intelligence. Whilst undertaking the challenges above and operating in a dynamic world that is constantly changing, engineers carry the responsibility of making important decisions. In order to ensure the safety of everyone involved, engineers must also follow a number of strict ethical principles throughout their activities. Failure to comply with these ethical principles may result in adverse outcomes. A major example of this is the case of the Tacoma Bridge collapse in 1940, where the third largest suspension bridge in the world came crashing down after experiencing wind speeds of 40-45 mph.1 The primary reason behind the collapse was described as "torsional flutter"2 which occurred due to "the ratio of the width of the bridge to the length of the main span being much smaller than those of previously constructed bridges and the bridge having less vertical stiffness".3 From a primary point of view, it may appear that the collapse of the bridge was due to an external factor that could not be controlled – high wind speeds- however, further investigations suggest that professional engineers may be held accountable for the collapse. Therefore, this essay will look into the ethical implications associated with this incident, including the moral responsibilities of the engineers along with the economic and social issues. In order to provide a well-rounded insight, The National Society of Professional Engineer's (NSPE) "Code of Ethics" and the Royal Academy of Engineering's (RAE) "Statement of Ethical Principles" will be used to explore these ethical issues.
Many of the problems arose before the construction of the bridge was underway. Firstly, the federal government refused to give financial support for building the bridge in 1932. Later on, Clark Eldridge completed the original bridge plan which cost $ 11million. However, due to the high costs, Leon Moisseiff redesigned the bridge with drastic modifications so it could be made with $7 million only, the allocated budget.1 Moisseiff's design was based on a new aerodynamic principle from Austria known as "deflection theory"4 which worked in theory but there was inadequate experiential knowledge and no suspension bridge of such length and slender proportions had ever been designed.5 From the aforementioned situation, it is evident that economic issues have impacted the design of the bridge, resulting in Moisseiff's less reliable design being chosen due to its lower cost. This clearly highlights the unethical stance adopted by the federal government which should have ensured that the safety standards were being met before assigning a budget for the project. Such budget restriction was likely to pressure the design engineers to reduce the costs of their design whilst sacrificing the quality and safety. Also, the government could have delayed the construction of the bridge until sufficient funds were available considering that the Tacoma bridge was not necessary and was mainly built to bypass having to use the ferry.6 Therefore, the government's persistence to proceed with construction at a lower budget may be seen as one of the initial factors contributing to the collapse of the bridge.
Moreover, one of the main ethical issues arises from Moisseiff's decision to use a completely new design for the bridge. Moisseiff did not act to the feedback provided by some engineers at the Washington State Highway Department who protested a change in design calling it "fundamentally unsound... in the interests of economy and cheapness."4 Instead, he decided to proceed with his design knowing that no bridge was ever built with such dimensions and that there was a minor risk element. From a professional ethical stance, Moisseiff should not have proceeded with the design knowing that the slightest chance of failure was possible, as this could affect the public's safety. Therefore, Moisseiff's decision can be seen as a breach of his duty ethics and a violation of code one of NSPE's "Code of Ethics" which states that "Engineers, in the fulfillment of their professional duties shall: Hold paramount the safety, health, and welfare of the public."7 On the other hand, Moisseif's design decision may be deemed ethical when considered using the ethical principle of utilitarianism and from an economical and environmental point of view. This is because Moisseiff's design was narrower, lighter and used far less steel making it $4 million cheaper than Eldridge's original design.10 Having a cheaper design meant that the government would economically benefit during the great depression and at the same time, Tacoma residents would also benefit by having the bridge built. Since the outcome of Moisseiff's decision was beneficial for most people, it can be seen that it satisfies the principle of utilitarianism and can be classified as an ethical decision. Also, by using a narrower and lighter design that incorporated less steel, Moisseiff has managed to comply with RAE's second statement in the "Statement of Ethical Principles" which states that "Engineers should take due account of the limited availability of natural resources."8 This reinforces the fact that Moisseiff's decision was ethical since the sustainability of the environment was one of his concerns when making the design. The extent to which Moisseiff's decision can be classified ethical and whether he is responsible for the bridge failure depends on the ethical stance being considered.
Furthermore, another ethical issue appears when considering the contractors' and workers' actions during the bridge construction.
Contractors decided to build the foundation piers using Eldridge's design and the rest of the bridge was completed using Moisseiff's design.6 This decision meant that the workers found difficulty finishing off the bridge and had to use many creative techniques such as packing girders in dry ice to get them to fit together.1When looking at the workers' actions through the ethical principle of duty, they would be deemed unethical because they should have reported the issue to a supervising engineer instead of coming up with their own solution. The contractors can also be seen to act in an unethical way since they should not have accepted the design contract before analysing the working conditions and the complexity of the design required. Competition for engineering contracts may have been the reason for the contractors to accept the contract straight away. In addition, it was noted by an engineer that "As soon as floor forms were started, noticeable oscillation occurred. This oscillation steadily increased while the bridge floor was placed, varying in intensity in accordance with wind conditions."1 It was also reported that the deck was moving up and down vertically in moderate wind conditions.9 The above conditions should have been sufficient for the workers to halt construction until a solution was found, but this was not the case in practice. Again, this reflects the worker's unethical approach; they were more concerned with completing construction rather than reporting the oscillations and attempting to find a solution. It can also be argued that the Lead Engineer project (Clark Eldridge) did not act in a professional manner and should have interfered to stop the construction. Eldridge was the main engineer responsible for supervising construction and failure to interfere means that he has breached RAE's third code. The code states
that engineers should be able to "identify, evaluate, mitigate and manage risks"8 and Eldridge has failed to identify and evaluate the dangers associated with continuing construction on a bridge that was already unstable. The fact that Eldridge was supervising the construction process and did not attempt to tackle the oscillations issue at an early stage, suggests that part of the blame for the collapse should lie upon him.
Last but not least, the efforts displayed by a few engineers after the construction of the bridge and before it collapsed can also be looked into. The bridge was opened in July 1940 and earned the nickname "Galloping Gertie" due to its peculiar wave-like motion and bouncing1 As a result, several attempts were done by Moisseiff and on-site engineers to install a number of remedial measures including tie-down cables, inclined stay cables, and dynamic dampers.1 Despite the ineffectiveness of these remedial measures, it can be argued that Moisseiff acted in an ethical way because the motive behind his actions was to ensure the safety of the public and this clearly obeys code one of NSPE's "Code of Ethics".7 In addition, the motion of the bridge was studied by F. Bert Farquharson, a civil engineering professor at the University of Washington. Professor Farquharson used two scale models of the bridge and conducted-wind tunnel studies to analyse the bouncing and twisting motion.4 Following his studies, Farquharson proposed two solutions (Figure 1) in order to reduce the movement of the bridge. However, there was not enough time to implement either of them as the bridge collapsed five days after the studies were concluded.5 Looking at this from an ethical point of view it can be concluded that professor Farquharson acted in an ethically responsible manner as he has managed to follow RAE’s second code in the “Statement of Ethical Principles”. The code states that engineers should “protect, and where possible improve, the quality of built and natural environments.”8 Farquharson’s proposal for modifying the bridge design clearly shows his attempts to try to protect and improve a built environment. In fact, this disaster might not have occurred if the engineers had enough time to apply one of his proposals. Finally, Farquharson should not receive any blame for the bridge’s collapse since he was not involved in the design or construction work and was only attempting to enhance the structure.
the new Austrian aerodynamic principle (that was not tested experimentally before) in practice meant that the public's safety was at minor risk. Hence, the previous decisions can be deemed unethical and their outcomes suggest that Eldridge, Moisseiff, the government and the contractors are all partially responsible for Tacoma's collapse. In contrast, Farquharson is not responsible for the collapse of the bridge as he acts in an ethically responsible manner, attempting to find a solution for the oscillations. To conclude, engineering failures are often associated with a deficiency in engineering ethics and to minimise these failures, professional engineers must prioritise moral standards and aim to follow the set ethical principles when making their decisions.
Engineering Ethics: The Tacoma Narrows Bridge Collapse
Engineering is a very important discipline that integrates into our daily lives. Engineers significantly contribute to the development of societies and always face the challenges of innovating and designing the most viable solutions for the future. Many great accomplishments have been achieved in the various fields of engineering such as the construction of towers and bridges as well as the development of artificial intelligence. Whilst undertaking the challenges above and operating in a dynamic world that is constantly changing, engineers carry the responsibility of making important decisions. In order to ensure the safety of everyone involved, engineers must also follow a number of strict ethical principles throughout their activities. Failure to comply with these ethical principles may result in adverse outcomes. A major example of this is the case of the Tacoma Bridge collapse in 1940, where the third largest suspension bridge in the world came crashing down after experiencing wind speeds of 40-45 mph.1 The primary reason behind the collapse was described as "torsional flutter"2 which occurred due to "the ratio of the width of the bridge to the length of the main span being much smaller than those of previously constructed bridges and the bridge having less vertical stiffness".3 From a primary point of view, it may appear that the collapse of the bridge was due to an external factor that could not be controlled – high wind speeds- however, further investigations suggest that professional engineers may be held accountable for the collapse. Therefore, this essay will look into the ethical implications associated with this incident, including the moral responsibilities of the engineers along with the economic and social issues. In order to provide a well-rounded insight, The National Society of Professional Engineer's (NSPE) "Code of Ethics" and the Royal Academy of Engineering's (RAE) "Statement of Ethical Principles" will be used to explore these ethical issues.
Many of the problems arose before the construction of the bridge was underway. Firstly, the federal government refused to give financial support for building the bridge in 1932. Later on, Clark Eldridge completed the original bridge plan which cost $ 11million. However, due to the high costs, Leon Moisseiff redesigned the bridge with drastic modifications so it could be made with $7 million only, the allocated budget.1 Moisseiff's design was based on a new aerodynamic principle from Austria known as "deflection theory"4 which worked in theory but there was inadequate experiential knowledge and no suspension bridge of such length and slender proportions had ever been designed.5 From the aforementioned situation, it is evident that economic issues have impacted the design of the bridge, resulting in Moisseiff's less reliable design being chosen due to its lower cost. This clearly highlights the unethical stance adopted by the federal government which should have ensured that the safety standards were being met before assigning a budget for the project. Such budget restriction was likely to pressure the design engineers to reduce the costs of their design whilst sacrificing the quality and safety. Also, the government could have delayed the construction of the bridge until sufficient funds were available considering that the Tacoma bridge was not necessary and was mainly built to bypass having to use the ferry.6 Therefore, the government's persistence to proceed with construction at a lower budget may be seen as one of the initial factors contributing to the collapse of the bridge.
Moreover, one of the main ethical issues arises from Moisseiff's decision to use a completely new design for the bridge. Moisseiff did not act to the feedback provided by some engineers at the Washington State Highway Department who protested a change in design calling it "fundamentally unsound... in the interests of economy and cheapness."4 Instead, he decided to proceed with his design knowing that no bridge was ever built with such dimensions and that there was a minor risk element. From a professional ethical stance, Moisseiff should not have proceeded with the design knowing that the slightest chance of failure was possible, as this could affect the public's safety. Therefore, Moisseiff's decision can be seen as a breach of his duty ethics and a violation of code one of NSPE's "Code of Ethics" which states that "Engineers, in the fulfillment of their professional duties shall: Hold paramount the safety, health, and welfare of the public."7 On the other hand, Moisseif's design decision may be deemed ethical when considered using the ethical principle of utilitarianism and from an economical and environmental point of view. This is because Moisseiff's design was narrower, lighter and used far less steel making it $4 million cheaper than Eldridge's original design.10 Having a cheaper design meant that the government would economically benefit during the great depression and at the same time, Tacoma residents would also benefit by having the bridge built. Since the outcome of Moisseiff's decision was beneficial for most people, it can be seen that it satisfies the principle of utilitarianism and can be classified as an ethical decision. Also, by using a narrower and lighter design that incorporated less steel, Moisseiff has managed to comply with RAE's second statement in the "Statement of Ethical Principles" which states that "Engineers should take due account of the limited availability of natural resources."8 This reinforces the fact that Moisseiff's decision was ethical since the sustainability of the environment was one of his concerns when making the design. The extent to which Moisseiff's decision can be classified ethical and whether he is responsible for the bridge failure depends on the ethical stance being considered.
Furthermore, another ethical issue appears when considering the contractors' and workers' actions during the bridge construction.
Contractors decided to build the foundation piers using Eldridge's design and the rest of the bridge was completed using Moisseiff's design.6 This decision meant that the workers found difficulty finishing off the bridge and had to use many creative techniques such as packing girders in dry ice to get them to fit together.1When looking at the workers' actions through the ethical principle of duty, they would be deemed unethical because they should have reported the issue to a supervising engineer instead of coming up with their own solution. The contractors can also be seen to act in an unethical way since they should not have accepted the design contract before analysing the working conditions and the complexity of the design required. Competition for engineering contracts may have been the reason for the contractors to accept the contract straight away. In addition, it was noted by an engineer that "As soon as floor forms were started, noticeable oscillation occurred. This oscillation steadily increased while the bridge floor was placed, varying in intensity in accordance with wind conditions."1 It was also reported that the deck was moving up and down vertically in moderate wind conditions.9 The above conditions should have been sufficient for the workers to halt construction until a solution was found, but this was not the case in practice. Again, this reflects the worker's unethical approach; they were more concerned with completing construction rather than reporting the oscillations and attempting to find a solution. It can also be argued that the Lead Engineer project (Clark Eldridge) did not act in a professional manner and should have interfered to stop the construction. Eldridge was the main engineer responsible for supervising construction and failure to interfere means that he has breached RAE's third code. The code states
that engineers should be able to "identify, evaluate, mitigate and manage risks"8 and Eldridge has failed to identify and evaluate the dangers associated with continuing construction on a bridge that was already unstable. The fact that Eldridge was supervising the construction process and did not attempt to tackle the oscillations issue at an early stage, suggests that part of the blame for the collapse should lie upon him.
Last but not least, the efforts displayed by a few engineers after the construction of the bridge and before it collapsed can also be looked into. The bridge was opened in July 1940 and earned the nickname "Galloping Gertie" due to its peculiar wave-like motion and bouncing1 As a result, several attempts were done by Moisseiff and on-site engineers to install a number of remedial measures including tie-down cables, inclined stay cables, and dynamic dampers.1 Despite the ineffectiveness of these remedial measures, it can be argued that Moisseiff acted in an ethical way because the motive behind his actions was to ensure the safety of the public and this clearly obeys code one of NSPE's "Code of Ethics".7 In addition, the motion of the bridge was studied by F. Bert Farquharson, a civil engineering professor at the University of Washington. Professor Farquharson used two scale models of the bridge and conducted-wind tunnel studies to analyse the bouncing and twisting motion.4 Following his studies, Farquharson proposed two solutions (Figure 1) in order to reduce the movement of the bridge. However, there was not enough time to implement either of them as the bridge collapsed five days after the studies were concluded.5 Looking at this from an ethical point of view it can be concluded that professor Farquharson acted in an ethically responsible manner as he has managed to follow RAE’s second code in the “Statement of Ethical Principles”. The code states that engineers should “protect, and where possible improve, the quality of built and natural environments.”8 Farquharson’s proposal for modifying the bridge design clearly shows his attempts to try to protect and improve a built environment. In fact, this disaster might not have occurred if the engineers had enough time to apply one of his proposals. Finally, Farquharson should not receive any blame for the bridge’s collapse since he was not involved in the design or construction work and was only attempting to enhance the structure.