Dynamic response of a structure used at pop concerts

During a pop concert, it is rare that everyone moves in the same way following the music. Some people will move enthusiastically, jumping or bouncing, some will sway and some will remain stationary, either sitting or standing. Those who are stationary will provide significant damping to the structure as observed from the previous demonstrations and thus will alter the dynamic characteristics of the structure and effectively damp the level of vibration induced by the movements of the others. This in part explains why the predicted structural vibrations induced by human movements, where stationary people are not considered, are often much larger than vibrations measured on site.

The effect of stationary people in structural vibration has been considered in the new version of the Interim Design Guidance [19.7] for predicting the response of grandstands used for pop concerts.