Frequency changes in frequency-based damage identification

Marian Ralbovsky, Stefan Deix, Rainer Flesch

Research output: Contribution to journalArticlepeer-review


The eigenfrequencies of a bridge are influenced by the environment and by structural integrity. The task of damage identification is to conclude structural integrity from measured eigenfrequencies. Environmental frequency changes are a negative effect that hinders reliable damage identification. In this paper, it is experimentally shown how temperature and traffic load affect the eigenfrequencies, and reduction of this effect using a frequency prediction model is presented. Random variations are described using a probability density function, and a damage indicator based on this function is proposed. The paper addresses the issue of reliability of damage detection considering random and systematic errors that are present in the eigenfrequencies extracted from measurements. Various damage scenarios are presented, both with identifiable and non-identifiable damages.
Original languageEnglish
Pages (from-to)611-619
Number of pages9
JournalStructure and Infrastructure Engineering
Publication statusPublished - 2010

Research Field

  • Former Research Field - Mobility Systems


  • damage identification; eigenfrequency variation; bridge monitoring; reliability of damage detection


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