On July 17, 1981 two walkway bridges collapsed in the Hyatt Regency Hotel in Kansas city, Missouri. The collapse of the walkway bridges resulted in the loss of 111 lives and injured 188 others. The disaster was due to a design flaw and human error to the load being doubled on the upper girder which led to the failure of the walkways when people were gathered on them.
The failure of the walkway bridge was due to changing the original design from one rod connecting the roof, fourth and second floors together to two separate rods connecting the fourth floor to the roof and the second floor to the fourth. This design change led to weight being held by the connections on the upper girder to double. Since in the original design the load of the walkways was supported by the hanger rods instead of the connections on the girder. The load on the grider can be calculated using F=mg, F= force applied to the grinder, m= the mass of the load, and g= the gravity. The doubling of the load on the grider in the final design was not taken into account which caused the walkways to not handle anymore force with people walking on them , which caused the failure.
The limits exceeded in the engineering disaster were the load forces, where the two walkways were supported by the bolt connections on the upper grider and that doubled the load on the connection which led to the failure once more load was added due to people standing on the walkways.
The limits were exceeded because the doubled load was not taken into account with the design change. The calculations were not re-evaluated with the design change, therefore they were approved without solid proof of safety.
The design failure occurred due to a lack of communication between the fabricator and the engineer, therefore not leading to the re- evaluation in the calculation after design change. Therefore it is very important and critical to run through calculations before setting anything in stone. Another lesson learned would be to never risk the safety of others for anything.
Communication and attention to details are very important aspects of becoming an engineer and should never be taken lightly as they can lead to the death of peoples.
This disaster has reassured engineers of the importance of re-evaluating and re-calculating everything multiple times and to not assume anything but rather always factor in the highest factor of safety to avoid such disasters.