Damage detection of a bridge model based on operational dynamic strain measurements

Vibration data analysis reserves a significant place in structural health monitoring practice since it can be employed for certain engineering problems such as locating damage and assessing damage severity by means of vibration signature interpretation. In this study, a damage detection study is carried out in light of vibration data analysis methods on a four-span bridge model by exploiting strain measurements. The concept of strain operating deflection shape along with an extraction method based on frequency and spatial domain decomposition is proposed. The damage-induced state of the bridge model is compared with the baseline state to detect and locate the damage. The result of strain analysis is also compared with acceleration analysis by simultaneous measurements of strain and acceleration. The power spectrum matrix of responses is estimated using digital signal processing principles. Besides the operating deflection shape analysis, operational modal analysis and correlation analysis of strain modes are conducted to identify and locate the damage.