Design of lightweight footbridges for human induced vibrations

Joint report prepared under the JRC-ECCS cooperation agreement for the evolution of Eurocode 3. Nowadays, it is well-known that for the structural safety verification of footbridges, and for the comfort guarantee of its users, it is fundamental to consider the effect of human induced vibrations, particularly: vibrations due to pedestrian traffic should be within acceptable limits for users; the lock-in phenomenon should be prevented; and, the footbridge structural safety should be guaranteed if subjected to intentional excitations. Recognizing a gap in lightweight footbridges design procedures, a guideline is presented in this document proposal for footbridges design taking into account human induced vibrations. First, the proposed methodology is detailed. Attention is devoted also to the response measurements, identification tests and instrumentation used in the evaluation of the dynamic properties of footbridges. The potential strategies to control the vibration response of footbridges are reviewed. Finally, three worked examples of application of the proposed design methodology are exposed, namely a simply supported beam and two existing footbridges.