Ferne Hotel walkway collapse
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Added by Nkr20Disaster
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Added by Nkr20
Added by Nkr20Inside the lobby, some had smashed windows trying to escape the building. First responders were initially overwhelmed with the number of injured and dead, and over 50 ambulances were dispatched to the scene.
Aftermath
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A total of 154 people lost their lives in the disaster, with the bodies of 119 people recovered from the hotel lobby and patio corridor, and an additional 35 having perished from injuries either en route to or after reaching the hospital. An additional 386 people were treated for injuries, approximately 25 of them being life-threatening.
On the morning of 19 May, president Daniel Burns ordered that all state flags be lowered to half-staff for three days, and designated 20 May as a National Day of Mourning.
Investigation
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Three days after the disaster, Charlie Dugan, a structural engineer hired by the Arvant Sun, discovered a significant change in the design of the walkways. The two walkways were suspended from a set of steel tie rods, with the second floor walkway hanging directly underneath the fourth floor walkway. The walkway platform was supported on three cross-beams suspended by steel rods retained by nuts. The cross-beams were box beams made from C-channels welded toe-to-toe. The original design called for three pairs of rods running from the second floor all the way to the ceiling. Investigators eventually determined that this design supported only 60% of the minimum load required by Arvant municipal building codes.
Freed & Sons Steel Company, the contractor responsible for manufacturing the rods, objected to the original building plan, since it required the whole of the rod below the fourth floor to be threaded in order to screw on the nuts to hold the fourth floor walkway in place. These threads would probably have been damaged beyond use as the structure for the fourth floor was hoisted into position. Freed & Sons therefore proposed an alternate plan in which two separate sets of tie rods would be used: one connecting the fourth floor walkway to the ceiling, and the other connecting the second floor walkway to the fourth floor walkway.
This design change would prove fatal. In the original design, the beams of the fourth floor walkway had to support only the weight of the fourth floor walkway itself, with the weight of the second floor walkway supported completely by the rods. In the revised design, however, the fourth floor beams were required to support both the fourth floor walkway and the second floor walkway hanging from it. With the load on the fourth-floor beams doubled, Freed & Sons' proposed design could bear only 30% of the mandated minimum load.
The serious flaws of the revised design were further compounded by the fact the both designs placed the bolts directly in a welded joint between two facing C-channels, the weakest structural point in the box beams. Photographs of the wreckage show excessive deformations of the cross-section. In the failure, the box beams split at the weld and the nut supporting them slipped through.