Abstract (EN):
The Infante D. Henrique Bridge is a concrete arch bridge with a span of 280m that crosses the Douro River at the city of Porto. The very delicate construction procedure required the installation of a static monitoring system that has been in operation since that phase. In September 2007, it was also implemented a dynamic monitoring system with the aim of investigating the feasibility of vibration based damage detection in the long term, by developing and implementing robust and objective operational modal analysis tools for continuous monitoring. This effort was preliminary described at Eurodyn 2008 [1]. This paper, after a description of the bridge and of the monitoring project, presents an overview of the state of the art tools that were created to perform the automatic identification of modal parameters, followed by a short description of the statistical models developed to study the effects on the continuously tracked bridge modal parameters of environmental and operational factors, such as temperature and traffic. At last, using the database collected during the last five years, the fluctuations of the bridge dynamic parameters is interpreted, highlighting the long term evolution of the natural frequencies, and it is shown that it is possible to minimize the effects of environmental and operational factors on the bridge modal parameters and then evaluate an index that is able to automatically detect eventual structural anomalies.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
8