Effect of the frequency content of earthquake excitation on damage detection in steel frames

In this study, the effect of earthquake frequency content and noise effects on damage detection has been investigated. For this purpose, the damage was defined as nonlinear behavior of beams and columns, and several ground motion records were scaled so that some elements yield under the applied excitation. Then the acceleration response data of each floor obtained using the nonlinear dynamic analysis. Using the discrete wavelet analysis, the occurrence and time of damage in a frame can be detected based on the spikes appearing in the wavelet details plots obtained from discrete wavelet decomposition. The mean period (Tm) was used to determine the frequency content of earthquakes. The implications of this parameter for the analyses with different ground motion records were investigated and the results showed that the records with low Tm are more suitable for structural damage detection. To investigate the effect of noise or measurement errors on damage detection process, the discrete wavelet analysis was repeated with a noise introduced to the acceleration response data.