Relation of Natural Frequencies to Traffic Pedestrians’ Comfort of Some Steel Footbridges

In this paper several aspects regarding the dynamic behaviour of the steel footbridge structures under the action of the loads generated by the pedestrians’ displacement, correlated with the traffic comfort of the pedestrians crossing the structure are presented. The crossing pedestrians’ comfort criterion requires the values of vibration frequencies and accelerations of the structures in certain limits so that the vibration amplification or resonance is avoided. The paper takes under investigation eight footbridges on steel, composite steel-concrete girders and a cable stayed structure from the viewpoint of frequencies in vibration Mode 1 in a vertical plane, generated by their own weight - natural frequency, or from a partial pedestrian loading, as well as the resulting resonance risk and the traffic comfort.