On the loads produced by crowds jumping on floors

This paper describes an experimental investigation to determine the dynamic loads produced by groups of people jumping and focuses on the changes in the characteristics of the load with increasing group size. Two floors were selected and subjected to forced vibration tests to determine their dynamic characteristics. The floors’ responses were monitored as groups of up to 64 people jumped in time to a musical beat. The recorded responses were then analysed to determine peak accelerations and displacements. The data were also processed to find the first three Fourier components of the load and these were used to derive the attenuation of Fourier coefficients with group sizes. A similar form of relationship for the fourth Fourier coefficient was determined. To complete the cycle, the load model was used to calculate the floor response for comparison with the measurements.