In the article, “I-5 and the Physics of Bridge Collapse,” Hartsfield (2013) has stated that most bridges including the I-5 bridge failed due to inevitable design flaws. The author implies the possibilities that can cause a bridge to collapse including construction errors or miscalculations for cantilever, and high external force for suspension bridges. According to Hartsfield (2013), “A truss bridge holds as long as the beams themselves don’t break and the joints stay together.” In this regard, a truss bridge can collapse once a part of the structural beam fails. He further states that the unfortunate tragedy of the I-5 truss bridge might have been due to the impact caused by a truck, as it crashed into one of the beams. Hartsfield also mentions that nevertheless, it is critical to understand the underlying problem to determine the actual cause of unpredicted collapse in bridges.
While truck collision has contributed to the collapse of I-5 truss bridge, I think that four main negligence factor played as the key roles to this catastrophe. First of all, Washington State Department of Transportation(WSDOT) should have ensure that every permit they gave out has oblige to the minimum vertical height clearance level. As WSDOT is responsible of acknowledging the proposed routes for company’s oversized vehicles; they should have checked that all registered vehicles are suitable to utilise the I-5 bridge before granting permission. According to a website from National Transportation Safety Board(NTSB), companies were not prompt to perform route surveys since WSDOT did not technically review permits in an authoritarian manner.
The drivers who are involved has conduce to the I-5 bridge failure. The pilot car driver should have taken more responsibilities in her duty of escorting the truck. According to the NTSB website, the pilot driver was on the phone when passing through the I-5 bridge. Furthermore, it was also reported that the antenna of the pilot truck was not straight which it is used to measure the vertical height. A message will be sent to warn the pilot about the danger if the truck behind is too tall to pass through the bridge. Therefore, one main factor for the truck driver collision with the structural beam is due to either the measuring system of the pilot car failed to operate effectively due to the misaligned antenna, or the pilot driver is too distracted to notice the warnings.
The truck driver should have followed the pilot car at a further distance. According to Ouellette (2016), “The driver was following the pilot car too closely.” The truck driver did not tail at a recommended distance, so even if the pilot driver did warn the truck driver about the vertical clearance height, the truck driver would not have an ample responsive time to avoid the collision.
Lack of attention to monitor the bridge is a notable factor for this disaster. According to NTSB, the data on bridge strike of the I-5 bridge is not diligently recorded, as well as the data for navigation system is not updated; and the collision of the structural beam with oversized trucks has happened multiple times. Preventive measures could have been set up to reduce the risk of the bridge failing, and at the same time have oversized vehicle drivers to be warned about the danger if these documents were managed attentively.
Lastly, design flaws of the I-5 truss bridge is another significant reason. According to an article, Ouellette (2016), “The key issue in this case is the variable vertical bridge clearance.” The I-5 bridge is constructed with a curve top. Vertical height changes throughout the different lanes; lane in the middle of the bridge is taller. Therefore, when the truck driver drove under the lower height lane to give space to another vehicle, it collided with the structural beam by two inches.
Human error in ergonomics is unavoidable. The new design of I-5 bridge should be reinforced to ensure that the height clearance level is same throughout the lanes. WDSOT should practice reviewing proposed route for all oversized vehicles strictly, and provide mandatory training for both truck and pilot drivers. A standardise database can be established for all transportation company to follow. At the end of the day, everyone needs to play their role solemnly to avert similar tragedy from happening again.
Reference:
Tom.H (2013, May 28).
I-5 and the physics of bridge collapse. RealClear Science.com. Retrieved from https://www.realclearscience.com/articles/2013/05/29/i-5_and_the_physics_of_bridge_collapses_106544.html
National
Transportation Safety Board. (2014). Washington State I-5 Bridge Collapse Abstract. Retrieved
July 15, 2011 from https://www.ntsb.gov/news/events/Pages/2014_I5_Bridge_BMG-Abstract.aspx
Jennifer.O
(2016, August 16). New analysis confirms why the skagit river bridge collapsed.
GIZMODO. Retrieved from https://gizmodo.com/new-analysis-confirms-why-the-skagit-river-bridge-colla-1785842162
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