1 A Disaster in Engineering : Paris Airport Terminal Collapse 2 A Disaster in Engineering : Paris Airport Terminal Collapse The demolition of terminal 2E in Charles De Gaulle Airport on 23 May 2004 was one of the disasters that put designing as a crucial factor in engineering. After a year of its unveiling, the terminal collapsed earlier in the morning of that day, leaving four casualties. It turned out that imperfect design and compromise regarding the designated budget and schedule led to this incident. It was indeed a failure in engineering, especially in the modern era. World famous architect Paul Andreu, who was also their chief architect since 1967, apparently wanted a futuristic formation of the airport that required a daring project. This disaster gathered attention regarding how pivotal designing is. This research will go through studies made from various sources and discuss why the incident occurred in the first place and what could have been done to prevent this collapse. A Rundown of the 2E Terminal of CDG Airport The Design of the 2E Terminal The innovative design of that terminal is indeed an example of architectural beauty. It aimed for a revolutionary design that marked CDG airport as the infrastructure to have it during that decade. 2E was connected to other terminals through a tube-looking transit, which was 110 feet wide and 1000 feet long. The terminal was designed to have a capacity of 25000 people and 3 an "isthmus" that connects the two buildings. The external view of the terminal had curved glass supported by metal struts, while the internal design had curve-formed concrete. The concrete shells had rectangular holes to let light in from outside. Simply, The entire building had a double shell assembly where the inner shell was reinforced with 12-inch thick concrete, and the outer shell was glass and aluminum. The metal struts consisted of 4-inch diameter and 8-inch diameter plates, which were embedded 4 inches deeper in the concrete shell. The inside of the vault did not have any outstanding supporting columns, which left free space for passenger movement. As a result, the view had a dramatic effect from inside the terminal (Loughran, 2006, p. 110-111). On the Day of the Collapse It was Sunday, 23 May 2004; a 110-foot portion of the terminal roof which had 98.5 foot long by 65.6 feet wide reinforced concrete and glass with metal tubes crumbled with little warning at 6:57 am, killing four passengers. The incident occurred with a loud cracking noise. The collapsed section was solid concrete and glass vault, so the number of casualties would have been much worse if it had happened during busy hours. The terminal remained shuttered for nearly four years as French officials continued investigating structural defects that led to this disaster (El Kamari et al. 2015, p. 89; Loughran, 2006, p. 112). Cautious Indications before the Incident Reports gathered from the witnesses revealed danger signs all over the structure before it collapsed abruptly. Around 6.45, a police lieutenant witnessed a tear in the concrete wall connecting the footbridge to the middle of the zone. Airport officials confirmed that two major pipes had burst two weeks before the incident. There were also reports made by the cleaning crew that there was concrete dust after the water leakage happened. Even before the disaster occurred, cracks were seen on columns while installing the first rings. The shell was deformed 4 over time, and transverse tearings were spotted in the midline of the shells (Baura, 2000, p. 60; El Kamari et al. 2015). What Went Wrong for the 2E Terminal Design Not Achieving a Certain Level of Ethics Architect Paul Andreu visualized the design of the 2E terminal in a manner which prioritized "form" over "function." Engineering designs have a specific code of ethics to follow to balance all the required attributes. The open space of the terminal did not have any supporting pillars and instead had an ambitious look, which compromised the structural stability. Designers often use the word "redundant" to express the supporting builds that include pillars or columns extending from floor to ceiling. These builds primarily aim for safety precautions and might be mentioned as "extra" to the designers. The 2E terminal(Roissy,CDG) had a decorative design and a kind of elegance to it. In this case,the pillars were looked at as redundant builds which would obstruct the structural beauty (Petroski, 2006, p. 187-188). But regardless of the downside, a fail-safe or safety backup is always necessary as support to prevent uncertain accidents or failures. As a result, there were fractures on the concrete lateral wall that connected the footbridge and it eventually collapsed on that day. Research Made from Case Study El Kamari et al. (2015) made a case study and it had been made using Ansys software to observe the progression of structural flaws. The terminal was modeled to examine the concrete structure's reliability and sensitivity. It turns out that the engineering design company did not consider the long-term effects of concrete and the thermal gradient load. After applying thermodynamic calculations, the obtained thermal gradient ranged from 7°C on the inside of the concrete shell and to -13°C on the outside (El Kamari et al. 2015, p. 92). 5 As for the sensitivity variable, the strength of concrete is the most extensive variable, which also means that a slight change in this value would cause major reliability issues. The reliability index found from the analysis was β of 1.824, but the obtained number is lower than the allowable value. From the report, it is safe to say that the terminal design had structural deficiencies from the beginning (El Kamari et al. 2015, p. 93-94). Low Budget for a Project A cut in the budget also played a role as a contributing factor in this incident. Trade unions in France revealed that builders were put under pressure to finish the project within time. Insufficient funding and high-quality results are what all contractors look for in terms of business. Tight on budget and time cannot ensure quality when required the most for the safety of the people. The project was also behind on its schedule. The construction was completed only 11 months before construction happened, and the overall expense was around $900 million. The repair project cost around $125 million more (Baura, 2000, p. 60; Petroski, 2006, p. 188). Mitigation of Stability through Weather Effects The case study also revealed that the temperature was shallow the night before and reached an unusual -20°C (El Kamari et al. 2015, p. 92). We know that heat is directly responsible for the expansion and compression of elements. The metal struts have a higher expansion rate than concrete and glass when it is exposed to heat. Because of the unusual increase and decrease of heat, the metal struts lost sufficient stability to support the concrete. This kind of disaster can also be categorized as a natural hazard related to civil engineering disasters where weather repercussions negatively impact. Supposing a design is not finalized with long-term weather effects taken into consideration. In that case, there is a higher chance that 6 the structure will not be reliable in terms of longevity, and this could also be regarded as human factors, including the lack of knowledge and prediction, which causes structural deficiency (Lili & Zhe, 2018). Conclusion From the research above, the collapse of the 2E terminal at Charles De Gaulle airport occurred because of two main factors- a design that favored aesthetics over function and a lack of awareness in work management. Although the flattened curved interior and the vast, spacious concourse were visually pleasing, the 2E terminal did not have enough constructional support to be durable enough in different circumstances. The final design also did not consider thermal effects, which would fluctuate the stability of the metal struts. Public infrastructures, including airports, are always crucial and should be constructed in a manner that would contemplate all the possible defects and shortcomings in the long term. The study also reveals that necessary time and management were not given to construction teams while having to limit the financial support. Slight awareness in engineering projects can cause major fatalities, and for that reason, professional engineering always has certain regulations of ethics to follow. From the study above, we can agree on the fact that human error is the main root of the problem when it comes to engineering disasters. Imperfect vision and lack of awareness may drive a project to its failure. The 2E terminal collapse is one of the examples where we can learn from our mistakes and finalize projects with balanced overall attributes. It would assist engineering teams in designing by taking all the possible outcomes of each concept into consideration instead of focusing on one main aspect. 7 References Baura, G. D. (2006). Engineering ethics : An industrial perspective. Elsevier Science & Technology. https://ebookcentral-proquest-com.libproxy.uregina.ca/lib/uregina/detail.action?docID=2 70109 El Kamari, Y., Raphael, W., & Chateauneuf, A. (2015). Reliability study and simulation of the progressive collapse of Roissy Charles de Gaulle Airport. Case Studies in Engineering Failure Analysis, 3, 88–95. https://doi.org/10.1016/j.csefa.2015.03.003 Loughran, P. (2006). Failed stone : Problems and solutions with concrete and masonry. Walter de Gruyter GmbH. https://ebookcentral-proquest-com.libproxy.uregina.ca/lib/uregina/detail.action?docID=3 36959 Petroski, H. (2018). Success through Failure: The Paradox of Design. Princeton: Princeton University Press. https://doi-org.libproxy.uregina.ca/10.23943/9781400889686 8 Xie, & Qu, Z. (2018). On civil engineering disasters and their mitigation. Earthquake Engineering and Engineering Vibration, 17(1), 1–10. https://doi.org/10.1007/s11803-018-0420-6