Numerical-Experimental Approach for the Vibrational Analysis of a Steel Footbridge

This study presents an in-depth investigation into the dynamic behaviour of a recently constructed steel arch footbridge located in the Marche Region (Central Italy). The main objective is to assess the vibrational response of the structure under operational conditions through a synergistic approach that combines experimental testing and numerical analysis. The experimental phase involved an on-site testing campaign aimed at identifying the global modal properties using Operational Modal Analysis (OMA) under ambient excitation conditions. Additional dynamic tests were carried out to evaluate the footbridge’s response to varying levels of pedestrian traffic, progressively increasing the number of participants, in accordance with the European guidelines HIVOSS and SETRA. In parallel, a finite element model was developed and calibrated based on the experimental data and used to perform vibrational analyses in compliance with current standards. The combined use of numerical modelling and experimental testing offers a comprehensive insight into the bridge’s vibrational behaviour and supports the development of alternative, more flexible testing protocols that better represent real operational conditions than current standard procedures. Furthermore, this approach could facilitate the implementation of new numerical analysis strategies to simulate the effects induced by pedestrian activity.