Experimental study on identification of stiffness change in a concrete frame experiencing damage and retrofit

X. T. Zhou, J. M. Ko, Yiqing Ni

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


This paper describes an experimental study on structural health monitoring of a 1:3-scaled one-story concrete frame subjected to seismic damage and retrofit. The structure is tested on a shaking table by exerting successively enhanced earthquake excitations until severe damage, and then retrofitted using fiber-reinforced polymers (FRP). The modal properties of the tested structure at trifling, moderate, severe damage and strengthening stages are measured by subjecting it to a small-amplitude white-noise excitation after each earthquake attack. Making use of the measured global modal frequencies and a validated finite element model of the tested structure, a neural network method is developed to quantitatively identify the stiffness reduction due to damage and the stiffness enhancement due to strengthening. The identification results are compared with 'true' damage severities that are defined and determined based on visual inspection and local impact testing. It is shown that by the use of FRP retrofit, the stiffness of the severely damaged structure can be recovered to the level as in the trifling damage stage.
Original languageEnglish
Pages (from-to)39-52
Number of pages14
JournalStructural Engineering and Mechanics
Issue number1
Publication statusPublished - 10 Jan 2007


  • Concrete frame
  • Neural network
  • Retrofit
  • Seismic damage
  • Shaking table test
  • Structural stiffness identification

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanics of Materials
  • Mechanical Engineering

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