Abstract (EN):
This paper reports the environmental effects on modal properties of the stress-ribbon footbridge of FEUP
Campus, based on experimental data acquired by a continuous dynamic monitoring system, with remote
control through the Internet, working permanently since June 2009, which comprehends a set of
piezoelectric accelerometers and temperature sensors. A toolkit in LabVIEW environment was developed
to process all the data collected by the monitoring system during almost one year, using an automated SSICOV
modal identification method and an algorithm for the evaluation of averaged vibration amplitude. It
is revealed that the natural frequencies are affected by both temperature and vibration amplitude caused by
pedestrians. Comparison of modal estimates obtained from ambient vibration tests performed in October
2009 and October 2004, as well as the continuous monitoring results demonstrate that these ambient
effects may mask subtle changes caused by possible damage. The application of Principal Component
Analysis on the natural frequencies effectively eliminates such effects, enabling the establishment of a
baseline to detect possible damage.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
15