Combining subspace approach and short time Fourier analysis for locating structural damage storeys

Chiung-Shiann Huang, Liane Jye Chen, Shih-Lin Hung, Chun Ting Ding, Wei Chih Su*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


This study proposes a novel and efficient approach for locating the floors of a building whose stiffnesses change after being subject to a strong earthquake. The floors that may be damaged are determined by comparing the unitary stiffness matrix in different stages in the life cycle of a building. To evaluate the coefficient matrices of a state-space model, the proposed procedure applies a subspace approach in conjunction with the short time Fourier analysis. The dynamic characteristics of a structure are determined from the coefficient matrices. Next, the unitary stiffness matrix is constructed by identifying natural frequencies and mode shapes. The effectiveness of the proposed procedure is verified using the measured earthquake acceleration responses of a three-storey structure that sustains damage on one or two floors and an eight-storey steel frame under a 200 Gal and a 1200 Gal earthquake, such as the Chi-chi earthquake that shook Taiwan on September 1999. The proposed scheme is compared to mode shape based approaches in identifying damaged floors, and is demonstrated to be superior to both MAC (Modal Assurance Criterion) and COMAC (Coordinate Modal Assurance Criterion).

Original languageEnglish
Pages (from-to)2480-2490
Number of pages11
JournalJournal of Vibroengineering
Issue number5
StatePublished - Aug 2015


  • Damage assessmen
  • Short-time Fourier analysis
  • Subspace approach


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