Summary- Reader Response Draft #3
In the web article “I-5 and the Physics of Bridge Collapses”, Hartsfield (2013) claimed that the concept behind a functional bridge design is what leads to its failure as well. The article examined the various types of bridges and found that the different types of bridges have weaknesses specific to themselves. One such example stated by the article is that truss bridges, which use geometric shapes as a basis for its strength and stability. As such, it is claimed by the article that deformations on the shape will cause the bridge to fail. Suspension bridges fail due to its inability to withstand huge external forces. The article observed that “when an external force causes the bridge to vibrate at its resonant frequency, it causes the vibration to grow stronger and stronger”. Another example of such a phenomenon are cantilever bridges. The article alleged that cantilever bridges are designed to be able to withstand the torque that the lever arm takes, yet failures are found to be due to construction oversight and overestimation of the torque it can take. The article concluded that understanding a bridge’s weaknesses is indispensable to uncovering the reason behind an unforeseen failure.
Based on the points elaborated in the news release, I agree to a certain extent that bridges might fail due to their own weakness in design. However, there are external factors like maintenance, natural disasters and manufacturing defects which might cause a bridge to fail.
Firstly, bridge failure could be due to poor maintenance. According to Schultz and Gastineau (2016) claims that bridges degrade due to exposure to different environmental condition, aging and “deicing chemicals”. This will cause the essential structure that is meant to rotate in becoming fixed, which results in increasing its internal force that damages the bridge. In addition, materials that corrode over time can cause “section loss” in steel members and concrete reinforcement. This results in weakening the structural integrity of the bridge and increase the likelihood of bridge failure. In my opinion, even having a good design for bridge stability and strength is not enough if there is no consistent maintenance checks on the bridge. This is one of the most common external factors on why bridges fail.
Secondly, natural disasters could also cause bridges to fail. According to Carey, Mason, Barbosa, and Scott (2019) states that despite having numerous simulation models on the effects of earthquake and tsunami hazards, there are still limitations when it comes to predicting damage it has on bridges. This shows that although there are many simulations that are trying to estimate the damage natural disasters have on bridges with, there are still no accurate answers for it. Flooding can also cause just as much damage due to debris such as trees and buildings that are lifted by the water and pushed forcefully against structural elements of the bridge. This shows that damage done by natural disasters is not only immeasurable, it can also do major damage by damaging the essential structural parts which causes the bridge to fail.
Lastly, bridge collapse could also be due to manufacturing defects. According to Ed Grabianowski (2011) states that looking back into inspection reports and witness accounts of the collapse, sometimes low-grade or faulty materials were used which make the bridges too weak to withstand “rigors of time”. For instance, the collapse of Silver Bridge in Ohio River in 1967. The collapse was due to manufacturing defects in one of the steel eyebars which held the bridge. This shows that even while having flawless design, manufacturing defects can also cause a bridge to fail.
In conclusion, although I agree to a certain extent that bridge failure might be due to its own design in stability and strength, it might also be due to external factors outside of its design.
References:
Carey, T. J. , Mason, H. B. , Barbosa, A. R. & Scott M. H. (2019, N.D.) Retrieved from ascelibrary.org https://ascelibrary.org/doi/10.1061/%28ASCE%29BE.1943-5592.0001353
Grabianowski, E. (2011, September 13). "10 Reasons Why Bridges Collapse" Retrieved from HowStuffWorks.com. https://science.howstuffworks.com/engineering/structural/10-reasons-why-bridges-collapse.htm
Schultz, A. E. & Gastineau, A. J. (2016, N.D) “Bridge Collapsed” Retrieved from Sciencedirect.com. https://www.sciencedirect.com/topics/engineering/bridge-failure
Based on the points elaborated in the news release, I agree to a certain extent that bridges might fail due to their own weakness in design. However, there are external factors like maintenance, natural disasters and manufacturing defects which might cause a bridge to fail.
Firstly, bridge failure could be due to poor maintenance. According to Schultz and Gastineau (2016) claims that bridges degrade due to exposure to different environmental condition, aging and “deicing chemicals”. This will cause the essential structure that is meant to rotate in becoming fixed, which results in increasing its internal force that damages the bridge. In addition, materials that corrode over time can cause “section loss” in steel members and concrete reinforcement. This results in weakening the structural integrity of the bridge and increase the likelihood of bridge failure. In my opinion, even having a good design for bridge stability and strength is not enough if there is no consistent maintenance checks on the bridge. This is one of the most common external factors on why bridges fail.
Secondly, natural disasters could also cause bridges to fail. According to Carey, Mason, Barbosa, and Scott (2019) states that despite having numerous simulation models on the effects of earthquake and tsunami hazards, there are still limitations when it comes to predicting damage it has on bridges. This shows that although there are many simulations that are trying to estimate the damage natural disasters have on bridges with, there are still no accurate answers for it. Flooding can also cause just as much damage due to debris such as trees and buildings that are lifted by the water and pushed forcefully against structural elements of the bridge. This shows that damage done by natural disasters is not only immeasurable, it can also do major damage by damaging the essential structural parts which causes the bridge to fail.
Lastly, bridge collapse could also be due to manufacturing defects. According to Ed Grabianowski (2011) states that looking back into inspection reports and witness accounts of the collapse, sometimes low-grade or faulty materials were used which make the bridges too weak to withstand “rigors of time”. For instance, the collapse of Silver Bridge in Ohio River in 1967. The collapse was due to manufacturing defects in one of the steel eyebars which held the bridge. This shows that even while having flawless design, manufacturing defects can also cause a bridge to fail.
In conclusion, although I agree to a certain extent that bridge failure might be due to its own design in stability and strength, it might also be due to external factors outside of its design.
References:
Carey, T. J. , Mason, H. B. , Barbosa, A. R. & Scott M. H. (2019, N.D.) Retrieved from ascelibrary.org https://ascelibrary.org/doi/10.1061/%28ASCE%29BE.1943-5592.0001353
Grabianowski, E. (2011, September 13). "10 Reasons Why Bridges Collapse" Retrieved from HowStuffWorks.com. https://science.howstuffworks.com/engineering/structural/10-reasons-why-bridges-collapse.htm
Schultz, A. E. & Gastineau, A. J. (2016, N.D) “Bridge Collapsed” Retrieved from Sciencedirect.com. https://www.sciencedirect.com/topics/engineering/bridge-failure
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