Damage assessment of base-isolated building using subspace identification approach

This paper proposes a damage detection algorithm of structural health monitoring (SHM) systems for a base-isolated building. The proposed algorithm mainly consists of the multiple-input multiple-output (MIMO) modal analysis and the physical parameter identification. Story stiffnesses as direct damage indices of the structure are identified using complex modal properties obtained by subspace identification. This algorithm is tuned for base-isolated buildings using model reduction to a single-degree of freedom (SDOF) system. The isolation layer and the superstructure are treated as separate substructures as they are distinctly different in their dynamic properties, so that the damage scenario for a base-isolated building is much simpler and more accurate than for a conventional building. Our strategy is to maximize the benefit of this simplicity. The effectiveness is verified through the numerical analysis and experiment.