Experimental and numerical dynamic structural analysis of footbridges when subjected to pedestrians walking loads

This research work aims to investigate the dynamic structural behaviour and assess the human comfort of footbridges, when subjected to pedestrian walking, based on experimental tests and tuning of finite element model. This way, the test structure is related to a real pedestrian footbridge, located at the Osvaldo Aranha Street, route of great importance and so very heavy traffic of vehicles along the day, next to the new Maracanã Stadium, in the city of Rio de Janeiro/RJ, Brazil. The investigated footbridge presents two spans with length equal to 29.5 and 24 m, respectively, and a total length of 53.5 m. Initially, to identify and assess the global dynamic structural behaviour of the structural model an operational modal analysis (OMA) was performed on the investigated footbridge. After that, several forced vibration tests were performed on the footbridge, considering the pedestrians walking with different step frequencies. In sequence, a finite element model was developed based on the ANSYS computational program. This model was used for the calibration of results, obtained based on the footbridge experimental monitoring. Finally, a human comfort assessment was performed, based on the comparisons between the results (peak accelerations), of the dynamic experimental monitoring and the recommendations provided by design guides HIVOSS and SÉTRA.