Serviceability conditions of pedestrian structures using a simplified moving mass model

Abstract

A simple mechanical model for pedestrian loading, consisting on a mass with a single degree of freedom that moves at constant speed along the footbridge, is presented. The footbrigde is modelled using a reduced number of beam 2D finite elements, simply supported at its ends. The dynamic interaction is ensured through direct requirement of contact conditions between the mass and the corresponding interpolated point in the beam. When the beam is massive enought, the results are similar to those obtained with models of mobile forces. However, if the beam is lightweight, the effect of the mass of the pedestrian can be significant, resulting in a more realistic modelling. The coupled model allows to study the interaction between the pedestrian and the structure and the results can be used to estimate by simulation the serviceability conditions of this type of slender structures under pedestrian loading.