Quantifying Differences Between Walking Locomotion on Rigid and Flexible Pavements

Abstract

This work explores the differences between walking locomotion on rigid pavement and a particular type of flexible pavements made of EVA75 foam having thickness of either 10 or 20 mm. The aim is to analyse how human movements, in terms of trajectories of different body parts, are influenced by rigidity of such pavements. This research line is ultimately directed towards evaluation of the influence of flexible pavement on the vibration perception by human test subjects walking over vibrating decks of lively footbridges and floors.

The experiments were carried out in the Structures Laboratory at the University of Warwick, UK. A part of a 20 m long walkway was monitored using six infrared cameras. Three test subjects, instrumented with reflective body markers were asked to walk over the walkway made of concrete. Nominally the same experiments were then conducted on the walkway covered with one 10 mm thick layer of foam (ethyl vinyl acetate EVA75) first, and then with two layers of foam having thickness of 20 mm. Mechanical properties of the foam and its influence on the vertical ground reaction forces (GRFz) depending on the number of layers are studied. The trajectories of the reflective markers attached to the human anatomical landmarks are traced using the Vicon motion capture system. Averaged amplitudes of movement for chosen markers are compared for walking over the three supporting surfaces. While the first peak in the GRFz decreases when increasing thickness of the foam the magnitudes of displacements and accelerations of all analysed markers increase. The findings reveal that human walking on surfaces of different flexibility can be characterised by acceleration of body segments as well as by the way the forces propagate through the body via skeletal system.