Characterisation of transient actions induced by spectators on sport stadia

In a wake of Hillsborough disaster of 1989, all stadia hosting major sport championships in the UK were converted from terraced to all-seated. Driven by spectators’ demands for improving the quality of their experience and organisers’ interest in increasing the capacity of their venues, a debate has arisen recently about the possible introduction of safe standing areas. Some issues have been already highlighted, mainly related to security aspects and comfort. This study investigates how the introduction of safe standing areas and the expected increase of the density of a crowd could impact the dynamic loading induced by the spectators and the resulting structural response. To this end an experimental campaign has been conducted in a laboratory delving into the effects of common actions performed by seated and standing cheering spectators. The data on dynamic behaviour of a lively test structure in both conditions have been collected, simultaneously with data on behaviour of the spectators. The forces applied by the spectators have been inferred using inverse dynamics, by analysing the structural response. The results are presented in the context of human-to-structure interaction and human-to-human coordination.