Prevention of large vibration of a structure excited by oscillators

A large-scale unexpected vibration is caused by pedestrians walking on a footbridge. We model a bridge and walking as a suspended platform and oscillation. In this study, we describe experimental results and numerical simulations of the horizontal vibration of a platform suspended by strings. The platform is excited by five oscillators in the experiment. The platform begins to vibrate considerably when synchronized phenomena of the oscillators occur. We investigate the effects of the damping and the natural frequency of the platform on the mode of vibration and the conditions of the existence of synchronized phenomena. On the basis of the results, the conditions of small vibration of the platform and effects of the number of oscillators on the large vibration are clarified.