Experimental Study of the Human Ability to Deliberately Excite a Flexible Floor

Human-structure interactions are not completely understood yet. This paper presents an experimental study focusing on the interaction between a human and a flexible support, with a major aim to better understand how the behavior of a human subject, bouncing on a flexible structure, adapts to the support motion. Exploratory experiments are undertaken with a 7m-span timber footbridge tested in the Human Motion Analysis Laboratory of the University of Liege. The movements of the coupled system composed of the subject and the footbridge are recorded by Motion Capture technology; the subject\textquoteright{}s 3-D body motion is defined by three important angles: ankle, knee and hip. The interaction between the subject and the footbridge is also quantified by means of force platform measurements. The experiments indicate an influence of the support amplitude and natural frequency on the phase shift between the oscillatory floor motion and the three angles characterizing the motion.