Output-Only Modal Analysis of a Footbridge Based on Compact-Bandwidth Regularization

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Abstract

Estimation of the modal parameters from ambient vibration plays a fundamental role in structural health monitoring. To this end, a new compact-bandwidth regularization approach is developed in this paper for output-only modal analysis. The approach manipulates only on the measured signal and does not involve the structural model. The key ingredient lies in the compact-bandwidth constraint, that is, an arbitrary structural mode shall be compact around the modal frequency in the frequency domain. Then, the alternating minimization algorithm is adopted to deal with the compact-bandwidth constrained modal separation problem. Practical application to modal analysis of a real footbridge is conducted to see the performance and effectiveness of the proposed approach.