In this paper, a novel modal identification technique based on wavelet transform and singular value decomposition (SVD) is proposed. Under the assumption that structural system is time-invariant and the ambient excitation forces are white noise process, structural acceleration measurements from multiple points are fed into a covariance-driven preprocessor firstly. The obtained time domain covariance responses are then transformed into time-frequency domain through the wavelet analysis. The SVD technique is then employed step-by-step along the time axis to extract the ridges from those wavelet scalograms. The extracted ridge scales and their corresponding skeletons can be used for structural modal parameter identification. An experimental study on the north cable pylon of the Sutong Bridge, the longest cable-stayed bridge of the world, is performed to demonstrate the proposed technique. The results prove its capacity in identifying structural modal parameter for large scale civil engineering structures.
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