Modal Identification of Damage in the Dowling Hall Pedestrian Footbridge

Resumo

The methods that stand out in damage identification are those rooted in vibration response analysis,
known as Vibration-based Damage Identification (VBD). This arises from the direct influence of deterioration on
the global and local dynamic responses of structural elements, leading to alterations in dynamic parameters. Modal
indices, such as modal curvature (MC) and modal strain energy (MSE), were evaluated for the Dowling Hall
pedestrian walkway using a finite element model that extracted three-dimensional vibration modes. Additionally,
a newly introduced index known as the resultant vector, which incorporates three-dimensional modal coordinates,
was also examined and compared with the other indices. The results showed that there is a strong correlation
between the location of the actual damage and the location predicted by the indices. The study further investigates
the influence of damage magnitude on the accuracy of the indices and analyzes how damages impact adjacent
beams. The objective is to minimize ambiguities in determining damage locations and to provide guidance for
inspection and structural integrity monitoring programs. In conclusion, the methods of MC and MSE presented
more satisfactory results in identifying the introduced damages, whereas the resultant vector method exhibited
certain inconsistencies. The study also observed minimal variations when applying damages of different
intensities, indicating heightened sensitivity primarily in lower intensities.