Statistical tools for the characterization of environmental and operational factors in vibration-based SHM

In recent years the interest in permanent monitoring of civil structures has raised because of the needs of controlling the ageing of a huge number of existing infrastructures. The recent advances in sensing technologies and data processing have made the installation and operation of permanent monitoring systems more and more attractive. Vibrationbased monitoring is based on the analysis of the evolution in time of damage features. A lot of these features are obtained from experimental estimates of the modal parameters. However, these estimates are usually influenced by environmental and operational factors. The variations they induce in the estimates may hide the small changes due to damage, so their influence has to be appropriately considered in practical applications. Using a large number of experimental data, models relating modal properties and environmental and operational factors can be set. However, the selection of the factors to be measured is typically not straightforward. As an alternative, statistical tools can be used to correct the estimates without the need to measure those factors. In the present paper, after a review of the available approaches to quantify the influence of environmental and operational factors, the opportunity of applying robust blind source separation techniques in this field is assessed. © The Society for Experimental Mechanics, Inc. 2015.