Theoretical and experimental analysis of the quasi-static and dynamic behaviour of the world's longest suspension footbridge in 2020

This work validates the simplified theoretical, analytical and numerical models used in the preliminary design stage of the 516 Arouca footbridge over the River Paiva (Portugal), the world's longest suspension footbridge. The models were used to define the configuration of the bridge under static loading and the eigenfrequencies excited under dynamic loading. The three-dimensional finite element model used in the detailed design of the bridge is briefly described. The paper also presents in situ experimental results. Tests were performed to study the static and dynamic behaviour of the footbridge under service loads and to assess the analytical/numerical modelling assumptions. The structure was subjected to loads generated by the wind and by a group of people crossing the bridge. Global Navigation Satellite System (GNSS) antennas were used to record the displacements of the bridge under quasi-static loadings caused by the people crossing the bridge at a slow pace. The data recorded by a set of seismometers allowed us to identify the natural frequencies and modes of vibration. The agreement between all the analytical/numerical solutions and the experimental data was found to be very good. The data recorded also allowed one to evaluate the damping coefficients of the bridge for the different vibration modes, something that is very difficult to predict in the design stage. © 2022 The Author(s)The authors would like to acknowledge the support provided by Arouca City Hall (Câmara Municipal de Arouca), with special gratitude to the President, Margarida Belém, and the Council Engineer, Conceição Oliveira; to the group of 34 volunteers for their time and patience; to the Portuguese enterprises MEO - Serviços de Comunicações e Multimédia, S.A and Geoide Geosystems SA, for the internet connection and GNSS antennas data, respectively; to LNEC (National Laboratory of Civil Engineering) for the anemometer data and their help in coordinating the group and the work; to Prof. Eduardo Kausel From MIT for his help with defining the analytical models. Finally, the authors would also like to acknowledge the financial support provided by the Spanish Ministry Science, Innovation and University (PID2019-109622RB-C21), and by the FEDER Andalucía 2014-2020 Operational Program (US-126491)