Dynamic response of floor systems to footfall-induced vibrations

Excessive floor vibration due to normal occupant-induced loads has become a more common serviceability concern in modern office floor systems. Current U.S. codes lack guidance and provisions that effectively deal with this concern, and typical analytical and numerical methods available for the evaluation of these floor systems are often time-consuming and somewhat complex for general application and routine design.; The objective of this study is to develop practical design guidelines, in the form of smoothed response spectra, for use in the design and evaluation of typical office floor systems excited by one individual walking at reasonable pacing frequency. These guidelines are based on multi-bay, multi-degree of freedom dynamic models of floor systems that adequately consider the mass participation of the entire floor, as well as response modes other than the fundamental ones. They also employ realistic load models that properly account for the spatial and temporal variability in the footfall-induced force, and incorporate the best available information on human perceptibility of vibration.; The smoothed response spectra provide a limit for tolerable peak velocity, in terms of total mass and damping, for the first mode of the floor. They offer to the design community a practical means which help determine whether a specific floor system may be problematic due to footfall-induced vibrations.