Damage detection of a structural health monitoring system for a seven-story seismic isolated building

Abstract

This paper proposes damage detection algorithm of a structural health monitoring (SHM) system for a seismic isolated building. The proposed algorithm consists of the multiple-input multiple-output (MIMO) modal analysis and the physical parameter identification. A story stiffness as a direct damage index of the structure is identified using complex modal properties obtained by subspace-based state space model identification (4SID). This algorithm is tuned for seismic isolated structures using substructure approach (SSA). Of a seismic isolated structure, the isolation layer and superstructure are treated as separate substructures as they are distinctly different in their dynamic properties. The damage scenario for a seismic isolated structure 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. The method is finally applied to an existing building in Japan. The monitoring target is a 7-story seismic isolated building with the gross floor area of 18606m² and with total height of 31m. This study shows potential to build a simple and reliable SHM system for seismic isolated buildings.