A new sub structure-based damage detection method is proposed in this paper to locate local damages in a structure. The method assumes a dense array of sensor instrumentation to a structure to enable damage localization in structural member level. The performance of the method is demonstrated using numerical simulation data sets obtained from seismic response analysis of a three-dimensional 5-story steel structure frame model which has artificially damaged beams and columns. The proposed method successfully detects and locates the structural member level damages in the structure.