The Kansas City Hyatt Regency Walkways Collapse - Case Study Example

Learning From Disaster Introduction The Kansas Hyatt Regency walkways collapse was one of the most devastating structural failures with respect to the injuries and loss of life. The structural failure left 200 victims injured and another 114 dead; in addition, the cost of damage was estimated at millions of dollars. At the time of collapse, the hotel had been in operation for just a year. At the beginning of the year, the design of the hanger rod connections was changed in a series of actions, and disputed communications between the engineering design team (G.C.E. International Incorporation) and the fabricator (Havens Steel Company). The design was changed from a one rod to a two-rod classification to shorten the assembly process, which doubled the load on the connector. This flaw was the ultimate course of the structural failure (Stagers, Baumann and Hakim, 2008). The evidence used at the Hearings had a number of implications for the principles involved; a number of engineers lost their licenses, and some firms went bankrupt due to the expensive legal suits. The incident thus served as a perfect example of the significance of meeting professional obligations, and the penalty for the professionals who underscores it. Cause Analysis of the Failure After a year of operation, about 1,600 people gathered in the atrium to watch or participate in a dance competition. The walkways were an ideal spot for great viewing angles, so about 40 people were collected on the one on the second floor, and another 20 on the one on the fourth floor. Apparently, the bearing load (the dead weight of the people in these floors) had exceeded the bearing capacity of the walkways; the fourth floor collapsed on the second one, making both falls on the ground floor (Ratay, 2009). About 111 people died instantly, and another three later during medication. Structural Failure The proceedings and uncertain communications between G.C.E engineers and Havens led to a change in design from a single to a double hanger rod box beam linkage for the fourth floor walkways. This change was requested by the fabricator to prevent threading the complete rod. The change was effected, and the contract’s Shop Drawing 30 and Erection E-3 were also changed. A few days later, 42 new shop drawings were sent to G.C.E., which included the revised drawings. Ten days later, the pictures were returned to Havens, complete with the stamp of Gillum’s Engineering review seal that further authorized the construction. The fabricator had used the guidelines from the American Institute of Steel Construction (AISC) standards, for the original design of the steel-to-steel links by steel manufacturers. However, as Chen (2005) referred to the Guide to Investigation of Structural Failure, the failure causes classified by connection type explains that “Overall collapse is originating from contact and joint failures occurred in structures with few or no redundancies. Where small strength connections recur, the failure of one has lead to failure of neighboring connections and a progressive collapse has occurred.” There were several sources of connection failures cited in the design drawings. The first flaw involved incorrect design as a result of insufficient factorization of all the forces acting on primary connections, the subsequent secondary connections, and the links related with volume modifications (2009). The next consideration was associated with an improper design using sudden section changes, leading to stress concentrations. The connections and the beams used in the design of the walkways were understated in the initial drawings, hence could not bear the sudden load from the concentration of people in those areas. The point was one of the many weak spots in the structural fishbone analysis. Third, there were insufficient allowances for rotation and movement. The design of the steel connections did not factor in the degree of flexibility that would enable the structure resist critical changes within its components as a result of varied loads (Stagers, Baumann and Hakim, 2008). The design flaw was further amplified in the unprofessional preparation of the mating surfaces and the fitting of joints. There were multiple weak points in the steel models, which meant that the structure was insufficient to bear the live load. The point was a major cause of the collapse. The other design consideration was observed in the deterioration of materials in the joints. Once the joints were structurally insufficient, there was abrasion on the connections due to unequally distributed load on the beams. Lastly, there was a lack of the thoughtfulness of large residual stresses originating from the manufacture or fabrication. The universal design standards dictate that the structural load bearing should have at least 20 percent overdesign of the actual load capacity, by way of overdesigning the structural components. If the design principle would have been considered, then the disaster would have not occurred (Stangenberg, 2009). As Chen (2005) reiterates, the structural factors comprise of the primary elements considered in any architectural design. The collapse of the walkways was so sudden and unexpected; it was a new, modern, and expensive place complete with luxury and class. The walkways were clearly modern and visually remarkable, their design not particularly revolutionary. In some instances, a certain degree of failure is anticipated. The design team was implementing and innovative design, without considering the possible consequences; the technology seemed to be perfected but was not subjected to sufficient engineering tests, and the setbacks were the price of the evolution. The disaster in Kansas City Hyatt-Regency Hotel was the consequence of several project management blunders that pooled to sanction a grave construction design setback to be installed in the bridges’ bearing system. It was so unfortunate that the dilemma was caught only when several lives were lost. Roof Collapse Eight months before the collapse of the walkways, part of the foyer roof collapsed while the structure was under repair. Therefore, the owner introduced the inspection team to analyze the structural integrity of the roof components. The primary objective of the investigation team involved examining the basis of the collapse and formed no commitment to inspect any engineering or design work outside the scope of their examination and indenture. In the same month, G.C.E. decided to undertake both the atrium collapse investigation, as well as a detailed design study of all the members consisting of the atrium roof. In addition, the engineering firm promised to inspect all the steel joints in the structures, beyond the scope of the roof inspection. Cause Analysis Problem Outline The Cause Analysis of the walkway failure identifies the collapse and the casualties sustained by the primary problems. The approach is based on presented facts that will guide in identifying other problems in the analysis process of the investigation (Stagers, Baumann and Hakim, 2008). The disaster occurred on July 17, 1981, around 7.10 PM; the day was characterized by unusual number of people on the walkways. Some of the hosts were engaged in substantial bodily movements (dancing) and swaying, which created abnormal movements of the structural components of the walkways. Lastly, the analysis captures the impact of the tragedy on the objectives of the subject organization, which in the case was the Hyatt Hotel. On a commercial standpoint, it is plausible for organizations to ensure that the safety of the employees and the guests remain within budget; this should ultimately help achieve the goals of the organization by minimizing property damage Ray, 2009). The deaths can be said to have affected the business’s safety goals. Correspondingly, the hotel’s reputation was on the line due to the imminent public relations fallout from the walkway collapse. In the analysis, the incident affected the customer goals of the business. Since the hotel had to be repaired after the incidents, subsequent repair and inspection costs were incurred. In the analysis, this can be seen to affect the production goals of the business. Apparently, the primary business objective was to make profits for the shareholders. However, after the occurrence, all the factors mentioned became critical for the realization of the actual goals of the business. The factors again put the credibility and the integrity of the contractors, the engineers, and the inspection team in question despite their experience and reputation in their industry. Problem Investigation using the Cost Analysis Model Using the goals affected by the event, a Cause Map can be build by developing some questions. The steps will help develop a Cause Map that will provide a detailed view of the incident; the approach provides more information used in the analysis (Stagers, Baumann and Hakim, 2008). The customer and the safety goals were adversely affected by the occurrence. The following schematic diagram elaborates the concept. Figure 1: Safety and Customer Aspect Analysis (Adapted from http://www.thinkreliability.com/InstructorBlogs/blog-KCWalkwayCollapseJul81) The Course Analysis of the event revealed a number of causal factors. The first one involved an inadequate structural design of the walkway. There was a failure of a weld, which subsequently allowed the support rod to pull round the box beam, leading to the failure of the walkways. Figure 2: Analysis of Design Failure. (Adapted from http://www.thinkreliability.com/InstructorBlogs/blog-KCWalkwayCollapseJul81) It was evident that the longitudinal weld did not have enough strength to support the overlying load, which in the case was the unequally distributed load from the dancing audience. The higher stress also emanated from the higher than usual number of people on the walkways. During the occurrence of the failure, about 20 people were gathered on the second floor walkway and about twice the same number on the fourth floor walkway. The two cases created a higher uneven load distributed across the beams (walkways), alongside the inconsistent structural design that formed a perfect recipe for the disaster (Stangenberg, 2009). When two situations are sufficient to produce and effect, the cause analysis integrates both on the object map using connectors as seen in the diagram below: Figure 3: The Impact of Combining Two Likely Situations to the Support Rod (Retrieved from http://www.thinkreliability.com/InstructorBlogs/blog-KCWalkwayCollapseJul81) The analysis reveals a fundamental optical representation of the situation as it occurred. The identification of the collapse mechanism proves useful in identifying minute details about the cause of the problem at hand (Chen, 2005). In the case, as said before, the weak weld on the connection was just but a web of flaws that were a disaster in waiting. The unusual crowd acted as the trigger mechanism for the manifestation of the design flaw. In addition, the design was seemingly changed without the consent of the structural engineer. The evidence for the affirmation is that the final design was dissimilar to the original design concept contained in the contract. Apparently, the changes in the design also resulted from a communication blunder between the structural engineer and the fabricator. The problem was not captured because the design re-evaluation process was ineffective. Initially, the structural engineer had sent a draft of a planned walkway design to the fabricator with the supposition that the latter would work out the fine points of the design. However, the fabricator supposed that the sketch was the finalized drawing. The assumption significantly changed the original concept of the design that considerably decreased the load bearing capacity of the beams. The changes related to the hanger rod joints; the fabricator altered the designs from a one rod model to a two-rod system, doubling the loading on the connector thus ultimately leading to the failure of the walkway (Stagers, Baumann and Hakim, 2008). Solutions for the Analysis The approach focused on finding specific solutions to problems by matching each to a particular cause. As detailed investigation confirmed, even if the original design concepts had been implemented, the walkway would have still failed due to the inability to hold the live loads on it. As Ratay (2009) affirms in his summary, analyzing the load, beam and column calculations at the design stage would have averted the disaster. The cause analysis concept revealed that neither side held accountability for the result. The primary concern then becomes the competency in determining at what stage one can consider an engineering project finalized. There should be clear procedures and actions, and a proper communication channel to prevent costly assumptions that will lead to disastrous structural failures. The cause analysis model thus proposes a simple, practical solution that involves implementing clear guidelines for determining the definitive accountability for a design. Another critical element to consider is the formal oversight of the project. It was discovered that the unapproved design changes were implemented by an ineffective design review procedure. The solution thus includes forming a formal design review process to oversee the entire design process. Lastly, the analysis reveals that the collapse was also caused by overdependence on a longitudinal weld that was not sufficient to hold a load on the members. The proposed solution would, therefore, be reinforcing welds and inspecting their integrity before using as a component of a structure. Bibliography Chen, W. (2005) Principles of Structural Design. Edited by W. F. Chen and E. M. Lui. London: Taylor and Francis. Ratay, R. (2009) Forensic Structural Engineering Handbook. 2nd ed. United States: McGraw- Hill Professional Publishing. Stangenberg, F. (2009) Lifetime-Oriented Structural Design Concepts. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg. Stegers, R., Baumann, D. and Hakim, N. (2008) Sacred Buildings: A Design Manual. Switzerland: Birkhauser Verlag AG. Read More