Ground reaction forces generated by runners-harmonic analyses and modelling

Abstract

Building structures carrying pedestrian traffc, e.g., footbridges, long-span floors and long cantilevered platforms projecting outwards from the walls (long balconies), can be susceptible to the dynamic influence of its users. One type of dynamic action that can occur on these structures is the dynamic action of people running. The main aim of this paper is to present the results of the harmonic analyses and mathematical models of two types of ground reaction forces (GRFs) generated by people applying different running techniques, i.e., forefoot-and heel-strike (rearfoot) running technique. The analyses of the GRFs were performed on the basis of the results of laboratory tests of running people and concern the vertical component of the ground reaction forces (VGRFs) generated by runners. The harmonic analyses were performed using Fourier transform. The results of the study show the main features and differences between forces generated by forefoot-and heel-strike runners. Data obtained for various running styles allowed the development of a load model proposal for the VGRFs generated by heel-strike runners. The results of the VGRF parameterization and the proposed new VGRF model allow the VGRFs generated by forefoot and heel-strike runners to be accurately estimated in the case of normal running pace (recreational running). The application of the presented results allows improvements to the accuracy of determining the dynamic response of structures induced by runners.