Seismic damage detection for a masonry building using aftershock monitoring data

The problem of detecting structural damage by exploiting vibration signal measurements produced from earthquake excitation is addressed in this work. Following the Wenchuan earthquake of 12 May 2008, a residential masonry building was selected for instrumentation with accelerometers by the Harbin Institute of Technology. This building had been damaged in the Wenchuan earthquake. It represents a rare case of an instrumented building that has been previously damaged, thus serving as a full-scale benchmark model to evaluate structural identification and damage detection methods. More than 20 earthquakes were recorded by the system after the building was instrumented. For detecting the structural damage, a vibrationbased damage detection algorithm for structures under earthquake excitation is introduced in this paper. This method is based on a residual associated with subspacebased modal identification, with global χ²-tests built on this residual. This method makes effective use of non-stationary and limited duration earthquake excitation, handles the uncertainties, and further detects the structural damage. The results obtained from these structural responses and earthquake excitations are reported using both identification and damage detection methods.