Aftershock monitoring of Wenchuan Earthquake for a residential masonry building

The purpose of this work is to obtain structural dynamic responses by exploiting vibration signal measurements produced by earthquake excitation. After the Wenchuan Earthquake in 12 May 2008, a residential building was selected to be instrumented with accelerometers by Research Center of Structural Monitoring and Control, Harbin Institute of Technology. This building has been damaged by the Wenchuan earthquake. It represents a rare case of an instrumented building that has been damaged, and thus can serve as a full-scale benchmark to evaluate and further develop structural damage detection and identification methods. More than thirty earthquakes occurred after the building was instrumented in that area, and 15 of them, which have been recorded, excited the building vibrating obviously. Both the earthquake excitations and structural dynamic responses are presented in this paper. With help of subspace-based modal identification algorithm, structural modal parameters, including frequency, mode shape and damping ratio were obtained from above data. The variety of structural modal parameters can be found under different earthquake excitations. Based on this work, farther vibration-based structural damage detection and safety evaluation can be applied on this structure, which also were discussed in this paper.