Modal identifiability of a cable-stayed bridge using proper orthogonal decomposition

M. Li, Yiqing Ni

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


The recent research on proper orthogonal decomposition (POD) has revealed the linkage between proper orthogonal modes and linear normal modes. This paper presents an investigation into the modal identifiability of an instrumented cable-stayed bridge using an adapted POD technique with a band-pass filtering scheme. The band-pass POD method is applied to the datasets available for this benchmark study, aiming to identify the vibration modes of the bridge and find out the so-called deficient modes which are unidentifiable under normal excitation conditions. It turns out that the second mode of the bridge cannot be stably identified under weak wind conditions and is therefore regarded as a deficient mode. To judge if the deficient mode is due to its low contribution to the structural response under weak wind conditions, modal coordinates are derived for different modes by the band-pass POD technique and an energy participation factor is defined to evaluate the energy participation of each vibration mode under different wind excitation conditions. From the non-blind datasets, it is found that the vibration modes can be reliably identified only when the energy participation factor exceeds a certain threshold value. With the identified threshold value, modal identifiability in use of the blind datasets from the same structure is examined.
Original languageEnglish
Pages (from-to)413-429
Number of pages17
JournalSmart Structures and Systems
Issue number3
Publication statusPublished - 1 Mar 2016


  • Cable-stayed bridge
  • Deficient mode
  • Energy participation factor
  • Modal identifiability
  • Proper orthogonal decomposition

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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