SSI for Stay Cables with an Alternative Stabilization Diagram

What is it about?

This study establishes a new methodology based on stochastic subspace identification for extensively identifying the modal parameters of a stay cable. An alternative stabilization diagram is further proposed to more conveniently stand out stable modal parameters of cable. Finally, a hierarchical sifting process including three stages is developed to systematically and automatically extract reliable modal parameters from the alternative stabilization diagram.

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Why is it important?

1. It is first found that that the lower limit for setting the time lag parameter can be decided by the ratio of the fundamental period of cable to the sampling time increment for a valid identification with the conventional stabilization diagram; 2. An alternative stabilization diagram is proposed to more conveniently stand out stable modal parameters of cable; 3. A hierarchical process including three sifting stages is developed to systematically and automatically extract reliable modal parameters; 4. The modal frequencies, damping ratios, and mode shape ratios for almost all the cable modes in the examined frequency range for three stay cable of Chi-Lu Bridge are obtained; 5. The modal frequencies and damping ratios of bridge deck from the ambient vibration signals of cable are effectively identified.

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