Unless they're willing to accept a percentage of failure, any structure that's hollow underneath should be designed by an engineer who can determine what activities it can and cannot absorb.
The pictures of this one seem that someone should've noticed and not let that large group of hyper teens dance in unison on that platform.
The section that collapsed was not part of the permanent stage. But put up by students stage hands. I heard there was also a piece of scenery that was in serious danger of being crushed by a dwarf.
That stage wasn’t long enough for generation of a propagated wave. It was just overloaded.
1981?
Well, Shiite happens...
I seem to recall that Napoleon’s Army was directed to break stride when marching over bridges.
I also recall that KC balcony collapse was a result of improper fastening on threaded rod hangers.