explain how the hyatt regency hotel walkway in usa collapse on july 17 1981
Hyatt Regency walkway collapse On the evening of July 17, 1981, approximately 1,600 people gathered in the atrium to participate in and watch a tea dance.[6] At 7:05Â p.m. local time (00:05 UTC; July 18) the second-level walkway held approximately 40 people with more on the third and an additional 16 to 20 on the fourth level who watched the activities of the crowd in the lobby below.[4] The fourth-floor bridge was suspended directly over the second-floor bridge, with the third-floor walkway offset several meters from the others. Construction difficulties resulted in a subtle but flawed design change that doubled the load on the connection between the fourth-floor walkway support beams and the tie rods carrying the weight of both walkways. This new design was barely adequate to support the dead load weight of the structure itself, much less the added weight of the spectators. According to the Seconds From Disaster episode, many of the survivors reported hearing popping noises coming from above them shortly before the collapse. Only moments later, the fourth-floor walkway suddenly dropped several inches under the spectators, before falling completely onto the second-floor walkway. Both walkways then crashed to the lobby floor below, resulting in 111 deaths at the scene and 219 injuries. Three additional victims died after being transported to hospitals, bringing the total number of deaths to 114.[7]