Robust modal identification of a large-span bridge with the new SpCF technique

When performing vibration tests on bridges, engineers face the challenge of extracting the global dynamic properties of these structures from the vibration responses measured at several degrees of freedom. In this paper, the new subspace-based poly-Reference Complex Frequency (SpCF) technique is applied to the vibration measurements of a large span bridge. The advantage of the SpCF with regard to other modal or system identification techniques is that it provides robust estimates for the modal properties, which leads to very clear stabilization diagrams. In order to assess the performance of the new SpCF, its estimates for the modal properties of the aforementioned bridge are compared to those of the poly-reference Least Squares Complex Frequency (pLSCF, also known by its commercial name polymax), which is deemed as a standard technique in experimental and operational modal analysis.