Damping ratio identification using attenuation responses extracted by time series semantic segmentation

•A time series semantic segmentation method is proposed to extract attenuation responses from long-term monitoring data.•The principles for selecting desirable attenuation segments to construct the semantic dataset are determined.•The long-term damping ratio of a continuous girder bridge is calculated with high reliability from the monitoring data.•The properties of damping ratio regarding the influence of calculation algorithms and the temperature effect are revealed.