ABSTRACT
When considering damaged structures, a modification of the response due to damage is observed. Variations in the behaviour of the system can be associated with the decay of mechanical properties.
In the context of this study, an arch bridge was subject to a demolition process, after the construction of a new steel bridge. During the demolition progression, several dynamic tests were carried out with different kinds of measurement sensors and different configurations. The main aim of the study is to give a dynamic assessment of the structure by evaluating its modal parameters from ambient output-only measurements, observing the effects of the damaging process. Therefore, it is appropriate to evaluate the modal parameters of the bridge, before and after the partial demolition, not only with the classical modal techniques aforementioned but also with a recently developed approach (Hong, 2010), called Enhanced Canonical Correlation Analysis. This technique, together with an advanced cluster analysis developed, helped to get consistent results which will confirm the unexpected behavior of the bridge before and after the partial demolition. All the experimental data are then used to update FE models representing the demolition procedure that will validate what has been captured in the field measurements.
