Dynamic Response and Control of Vibrations in Four Medium Span Steel Footbridges

Resumen

The design and performance of four footbridges in Slovenia and Spain were analysed recently to address the dynamic response and control of vibrations in medium span (25-50 m) steel footbridges. A comparative analysis of the four footbridges being studied was done, three of them already in service, in order to define the main dynamic characteristics and behaviour of medium span steel footbridges. The study includes dynamic load models and analysis considered (response spectra method and time history analysis), as well as the comparison of model predictions to experimental results from dynamic load tests. The article shows the sensibility of medium span steel footbridges to vertical vibrations induced by pedestrians, and considers the inclusion of tuned mass dampers (TMD) as an effective and easy to implement system to improve their dynamic response, reducing the vertical accelerations to meet the required comfort criteria.