Operational modal analysis method in the study of a bridge dynamics

Modal analysis allows to determine natural frequencies, modal damping ratios and mode shapes of mechanical structures. This paper presents a case study of application of the operational modal analysis to testing of a bridge during its normal service. The main purpose of the research was to determine the natural frequencies and mode shapes for the purpose of assessment of the bridge’s truss condition. In the paper a method of verification of the recorded measurement data quality as well as results of estimation of modal parameters are presented. The results of the carried out investigations were used by the manager of the bridge to plan the bridge truss’ renovation