Typical spectator movements were simulated by persons individually on a force platform with which dynamic force components were measured. Impulsive loadings are produced by movements such as rising, sitting, or jumping off the floor, while continuous loadings are generated in repetitive motion such as swaying, bending and straightening knees repetitively in place, jumping or dancing. Descriptive parameters derived from statistical and spectral studies of the load samples are presented. In particular, the vertical components of the impulsive loadings are modeled as random forcing functions, and a narrow‐band live load spectrum is proposed for checking potential resonant response of a structure to coherent crowd jumping for serviceability and human comfort. Resonant vibration of a structure can be reduced considerably by installation of energy‐dissipating devices. A revised design methodology for assembly structures is proposed to insure both structural integrity and functional serviceability.