Environmental vibration data analysis for damage detection on a civil engineering structure

Management of the useful life and safety performance of the infrastructure of a motorway network is currently a topic of great interest. The dynamic behavior of civil engineering structures has usually been studied by means of ambient vibration observations, analyzing them with methods of Operational Modal Analysis and the so-called Peak-Picking technique. The present paper reports the results of an alternative multivariate statistical approach, specifically Principal Component Analysis (PCA), for ambient vibration data, collected to detect suspected structural damage on some specific highway bridge spans in Sicily. The method consists in comparing the system structures of undamaged spans with that coming from a suspected damaged one, as designated by optimal subspaces determined by PCA. The distance between the subspaces, measured by means of the maximum principal angle between them, provides evidence regarding damage in the span under investigation.