Resumo (PT):
Abstract (EN):
The development of efficient vibration based structural health monitoring
systems requires distinguishing between abnormal changes in modal parameters caused by
structural damage and normal changes due to varying environmental conditions. In this context,
this paper is focused on the analysis and extraction of effects of temperature oscillations on
natural frequencies of a footbridge, where a long-term dynamic monitoring system was installed
by the Laboratory of Vibrations and Monitoring of the Faculty of Engineering of University of
Porto. With that purpose, firstly, the temperature influence on the natural frequencies is
reported, and correlations between measured temperatures and estimated natural frequencies are
analyzed. Then, the Principal Component Analysis (PCA) and the Novelty Detection method
are applied to identified natural frequencies: PCA effectively eliminates environmental
influence; Novelty analysis on the residual error of PCA predicted model is used as a statistical
indication of damage. The proposed procedure is illustrated using continuous dynamic data
collected from the footbridge during more than one year.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
8