Knickerbocker Theatre Collapse - Reasons for failure of the roof and lessons learned from the same.

1. Presented By
Things Simplified
( A New Perspective )

2. 
 It was a movie theatre situated in Washington D.C., United States at 18th street
and Columbia road.
 The Knickerbocker Theatre was commissioned by Harry Crandall in 1917.
Architect Reginald Geare designed the theatre with a seating capacity of 1,700
 The theatre roof collapsed on January 28,1922 under the weight of snow from
two day storm later named as knickerbocker storm which took around 100 lives
and left around another 130 injured.
 At the time of collapse theatre was showing Get Rich Quick Wallingford.
Knicker-Bocker Theatre

3. 
 Number of investigations were conducted to know the cause of failure of roof
of theatre.
 The change in the original design was attributed as the main cause of failure of
the roof. No recalculation of forces were accounted for change in design of the
roof.
 Moreover, the steel girders used to support the concrete slab were not fixed on
the supporting walls as a result of which the bearing to the steel girders was
not adequate and kept on changing due to expansion and contraction of wall
in summers and winters.
 The storm added to the problem by constantly accumulating the weight of
snow over the roof which ultimately led to the failure of bearing of the steel
girder on the wall.
Major Causes of Failure

4. 
 In the event of change of structural design of a structure, recalculation of
forces and design must be done to account for the changes.
 Proper bearing and support conditions must be ensured to transfer the loads to
the foundation without failure.
 The roof in the snowfall struck area must be designed in such a way that it
doesn’t allow for the accumulation of snow on it. For example, roof can be
sloped to avoid accumulation.
Lessons Learned

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7. 
 Knickerbocker Theatre Collapse
https://www.youtube.com/watch?v=XVWafCbfqHU
Video References