Human-induced vibration analysis and human comfort assessment of pedestrian footbridges

Resumo

The design of pedestrian footbridges has always been challenging. Essentially, this type of structure
presents long spans and, due to more resistant materials, the structural elements slenderness has been
considerably increased. Consequently, the excessive vibration problems become more evident and may cause
discomfort to the pedestrians or even structural risk. Therefore, aiming to predict the dynamic structural response
of footbridges induced by human walking, two mathematical models were used: single force model and
biodynamic models. Based on the use of the two loading models, an extensive parametric study was carried out
considering the pedestrian step frequencies, the pedestrian-footbridge mass ratios and the structural damping
rate. The results obtained along this investigation shows that the influence of the human walking depends on the
relationship between the mass of the pedestrians and the footbridge, and the pedestrian-footbridge dynamic
interaction effect can be irrelevant for small mass ratios. On the other hand, the human walking can, without any
doubt, provoke higher dynamic structural responses, especially when the footbridge fundamental frequency is
close to the pedestrian step frequencies’ range. In this situation, the structural system can reach high vibration
levels that can compromise the footbridge user’s comfort.