The Collapse of the Walkway in Kansas Hyatt Regency Building - Literature review Example

Name Course Task Date Introduction Structural failures may be very costly in terms of rehabilitation, and loss of life and business (CRC Construction Innovation, 2002). The causes of structural failures can be identified and accessed, and by applying the correct criteria for analysis, the impending disaster may be avoided. Thus, it is appropriate to apply the right and suitable methods of investigation of failure to achieve the reliable conclusion. The structural failure can be in the form of catastrophic collapse or deviation from the design expectation or deficiency of performance. A collapse is mainly caused by inadequate strength, while the deficiency in performance is caused by deterioration (Kreimer et al., 2003). The deficiencies can be determined using stress analysis on the body when subjected to load condition. The tool used in equilibrium analysis is free body diagram of forces acting on a body. The point is that if the diagram is drawn incorrectly in design, there will be inaccurate calculation of forces acting on the body and the system may fail (Gambhir, 2011). One of the failure in construction occurred in Hyatt Regency Crown building in Kansas City, Missouri in 1981, when the second and the fourth floor of the building crashed to the ground, leaving 114 people dead and 200 others injured, making it one of the worst disaster in structural failure in US history (Marshall et al., 1982). The building was opened a year earlier after four years of design and construction. It is a 40 storey building with an atrium and a function block. It also had three walkways spanned the atrium which covered 36m by 44m with 15m height between the second and the fourth floor. The walkways occupied the space between the function block and the tower. The walkway in the 3rd floor was also perched on the atrium ceiling by hanger rods with a diameter of 32mm, but the walkway in the 2nd floor was hanging from the walkway on the 4th floor, that was also connected to the ceiling (Marshall et al., 1982). The atrium roof had collapsed during construction due to flawed connection between the steel to concrete and insufficient provision for movement due to expansion in the connection. G.C.E. Engineers who were contracted to check the connections did not find anything to cause fear. During the collapse, the walkways for 2nd and the 4th floor collapsed on the 1st floor, killing and injuring the occupants on the first floor level of the atrium and those on the walkway on the second floor (Marshall et al., 1982). The causes of collapse The overall collapse resulted from the failure in connections within the structure (Kreimer et al., 2003). There were a series of failures in the connections, where one failure led to another failure in the neighbouring connection resulting in the progressive failure. It began with the hanger rod pulling through the box beam, which led to the failure of the connection that supports the fourth floor walkway. If the structure was redundant, and if there was alternative load paths, the other hanger rods could have carried the load on the walkways. However, this was not the case. It was not possible for the other rods to handle the increased loads after the failure of the adjacent rod. This failure caused the collapse of the two walkways (Bremner et al., 2006). a) Poor design owing to improper deliberation on the all the forces acting in the connections, specifically those affected by expansion. In building design, free-body diagrams are used as the main tool for analyzing the forces associated with the body. The forces need to be drawn properly; otherwise the forces acting on the body may not be calculated correctly, making the design to be unsafe. The significance of this using the right body diagram is illustrated by analyzing the collapse of the walkway in Kansas City Hyatt Regency building. If the force of the box beam is isolated against the nuts, it is found that the forces transferred will change in the new design. The resulting load is twice the original load; hence it failed (Marshall et al., 1982; Christianson et al., 2011). Load path Load path determine how vertical or horizontal loads are transferred to various components. In design of structures continuous load path should be taken into account, as it shows how load is transferred from one components structure to another before it is finally transferred to the ground (Federal Emergency Management Agency, 2000). Havens steel, the fabricator, simplified the fabrication process by using a two-rod system, hence, doubling the weight on the fourth walkway beam, because the beam would have to support the second floor load as well. In other words, the change in design resulted in a new load path that produced a compounding shear stress to the fourth walkway beam (Christianson et al., 2011). b) Poor design that led to abrupt change in some sections leading to concentration of stresses. The detail of the hanger rod used in the second and the fourth walkways floors was in departure from the original design. Originally, the arrangement for each of the hanger rod was to run continuously from the hanger connected to the atrium roof frame to the walkway in the second floor. In other words, the second floor walkway and the third walkway floor were supposed to be suspended from the same rod and held in place through a nut like as shown above. The original design load that would have been transferred to each of the hanger rod in the 2nd walkway floor could have been 90kN. Essentially, equal load could have been carried by each of the hanger rod at the 4th walkway floor, and the design load on the lower part of the hanger rod could have been half the load on the upper part, though the design weight would have been identical on the both hanger rod connections on the box beam (Christianson et al., 2011). The initial design, however, was not practical because it required 6.1 m long nut that would have extended to the hanger, without sleeve nuts. Therefore, the contractor made some modifications in the design to allow two hanger rods to be used instead of using one. The new design resulted in the increase in stress exerted on the nut on the bottom portion of the fourth floor walkway beam. This was because the nut was carrying the weight of two floor walkways instead of one (US, 1984). The modification did not change the design load transferred by the second floor walkway connections to balance the loads on the lower and the upper part of the hanger rod. Thus the load transferred from the 4th floor walkway beam on the upper portion of hanger rod was twice, making the situation to be worse. In this arrangement, the fourth floor hanger rod beam- hanger rod connection would be 181kN (Christianson et al., 2011). The inspection carried out by engineers did not bore fruit. One of the reasons is because the connection was concealed and could not have been noticed easily. Also during the construction, the engineer approved the change in design without checking it (Marshall et al., 1982). If the changes in the hanger rod were not made, the overall hanger rod – box beam connection capacity could not have met the expected design for connection Kansas City building code. The minimum load capacity for the connection would have been 152kN. But the capacity for the single rod connection was 91kN, which is approximately 60% of the required connection design (Christianson et al., 2011). c) Poor welding Poor weld on the fourth floor walkway beam contributed to this incident. This is because the steel walkway box beams split open ripped out from the hanger rods which were connected to the atrium roof. The major question that need to be answered is that why was so much weight placed on the beam that was meant to support. As if that was not enough, large sizes of washers were not used to distribute the load on the beam uniformly. Other reason for the collapse which may have contribute include inadequate provision for movement due to expansion and rotation, material degradation in the joints and non consideration of residual stresses caused in fabrication of materials (Ambekar, 2007). Other causes Based on the evidence suggested so far, there are various factors that may have contributed to this collapse. One of them involves the sizes of the washers on the hanger rods. Washers were too small for them to hold the hold large weight. Investigation showed that the rods with the washers went through the beam (Taylor and Moncarz, 2000). Taylor and Moncarz (2000) studied comprehensively of the structural design especially the demand to capacity ratio for the components. Each walkway floor consist of metal floor and a lightweight concrete sitting on I-beam whose dimensions are 16 inches deep and weighed 38.7 Kg per meter. The transverse beams were welded together toe to toe forming a box with 8 inches deep and weighs 12.7 Kg per meter. In addition, the beams were supported by rods which were connected to the beams by drilling holes through the welds. The capacity of the beam was further reduced after flattening the bearing area for the hanger rods by grinding. As a result, the connection could only support 30% in the required load (Taylor and Moncarz, 2000). This explains why the walkways floor collapsed far below the required load. The resulting structure failure is shown in the figure below. The hanger rod after the failure Significance of the investigation It is important to study the past construction failures and learn the lessons inherent in them. Proper investigation of the building collapse provides an opportunity to study the construction failure in order to learn their lessons so that the failures can be avoided in future. Thus investigating bodies like Standing Committee on Structural Safety (SCOSS) have provided reports on failure such as Kansas City Hyatt Regency building collapse and has provided recommendations for future buildings. Such reports provide documentation about the cause and the consequence of the incidence. In some cases remedial implementation of these measures and reconsideration of these lessons from the past incidences can be helpful in avoiding the repetition of similar failures (In Campbell, 2001). Conclusion This case underscores the importance for the clarity in design and design change control. There was never clarity on the overlapping responsibilities and complex relationships that could have been overcome through proper management that include eligible engineering process and proper communication. There should be independent review that will take into account critical safety issues. This will ensure that small details in building design are not overlooked. The lessons learned from this failure include The design process must ensure that all connections are analysed. A comprehensive review must be performed to ensure that all the details in the drawing are taken into account, not simply spot checking Any change in design must be hand formally through normal review process. Changes in design must be communicated properly to ensure that the parties involve can analyse the new design References Ambekar, A. G. (2007). Mechanism and machine theory. New Delhi: Prentice-Hall of India. Bremner, I., British Broadcasting Corporation., BBC Education & Training., & BBC Active (Firm). (2006). Kansas City: Death by design. French Forest, NSW: BBC Active (distributor). Christianson, J., Cruz, M., & Nolan, K. (2011). Hyatt Regency Hotel walkways collapse: Engineering failure. Seattle, WA: Seattle University. CRC Construction Innovation. (2002). Whole of life cycle cost analysis in bridge rehabilitation. CRC for Construction Innovation. Federal Emergency Management Agency, (2000). Risk Management Series; Safe Rooms and Shelters: Protecting People against Terrorist Attacks, FEMA Gambhir, M. L. (2011). Fundamentals of structural mechanics and analysis. New Delhi: PHI Learning. In Campbell, P. (2001). Learning from construction failures: Applied forensic engineering. New York, N.Y: J. Wiley and Sons. Kreimer, A., Arnold, M., & Carlin, A. (2003). Building safer cities: The future of disaster risk. Washington, D.C: World Bank. Marshall, R. D., Center for Building Technology., & Center for Materials Science (U.S.). (1982). Investigation of the Kansas City Hyatt Regency walkways collapse. Washington, D.C: U.S. Dept. of Commerce, National Bureau of Standards. Marshall, R. D., & National Institute of Standards and Technology. (1982). Investigation of the Kansas City Hyatt Regency Walkways Collapse. Building Science Series (Final). S.l.: s.n.. Moncarz, P. D., & Taylor, R. K. (May 01, 2000). Engineering Process Failure—Hyatt Walkway Collapse. Journal of Performance of Constructed Facilities, 14, 2, 46-50. National Emergency Training Center (U.S.)., & Kansas City (Mo.). (1984). Hyatt Regency skywalk collapse: Kansas City, Missouri, July 17, 1981. Emmitsburg, Md: National Emergency Training Center, Learning Resource Center. Read More