Group 3 Leonard Doyle Mairead Ní Choine David Kettle Robin Linsay

 The construction of the hotel began in 1978 and it opened on 1 st July  Consisted of a large atrium with three skywalks above the foyer.  2 nd floor walkway was located directly above 4 th floor walkway and 3 rd floor walkway was offset.  On 17 th July 1981, large crowds attending a dance in the atrium crowded the skywalks.  2 nd and 4 th floor walkways fail and fall to foyer below killing 114 people and injuring over 200.

 Design Change  Original design intended walkways to be supported by three cross beams suspended from three steel rods.  The rods were to run all the way from the 2 nd floor walkway to the ceiling passing through the beams of the 4 th floor walkway.  These rods would be threaded through the beams of the walkways and held in place by nuts.

 Steel manufacturers decided to change the design which the engineers approved without checking  The new design would mean that instead of the single threaded rods running from the 2 nd floor through the 4 th floor to the ceiling, shorter rods would be used. The 2 nd floor walkway would now have to be supported by the 4 th floor beam. This was the fatal design flaw.

 Due to the addition of a 2 nd rod, the stress of the nut under the 4 th floor beam doubled and it was now supporting the weight of two walkways instead of one.  There was an added load of people on the floor leading to imposed weight and vibrations.  The design of the cross beams made the structure even more exposed – C sections welded together and holes for the bolts placed on the weld joint.  When the 4th floor walkway was faced with this loading it caused the bolt to first bend the lower flange of the beam eventually fracturing the welded joint and tearing straight through it  The forth and second level walkways collapsed and fell to the ground.

 Gillum, Duncan and GCE were charged with gross negligence, incompetence and unprofessional conduct.  All their engineering licences were revoked.  $140million was paid out to victims and their families in damages.  ASCE adopted a report that said structural engineers have full responsibility for design projects.  Lobby was reconstructed and the walkway on the 2 nd floor is supported by columns underneath