Vibration characteristics of a suspension footbridge

A suspension footbridge located in a tourist attraction in Singapore has a suspended span of 35 m and was designed for static pedestrian and wind loads. In common with other bridges of this type, it is a light, efficient structure and has a lively dynamic performance. Distributed parameter and finite element models were used to understand the vertical plane behaviour of the bridge and a prototype dynamic test using impact excitation was conducted to check the models and investigate the dynamic response. The first two vertical vibration modes were found to occur at the same frequency, 2 Hz, as the average pedestrian footfall. Response to pedestrians was simulated using linear and non-linear models of a moving excitation source. (C) 1997 Academic Press Limited.