Estimation of residual deformation of building structures using singular spectrum analysis for a safety assessment

Abstract

Inter-story drift or roof drift plays an important role in the damage assessment of building structures. Hence, three performance levels regarding drift limits for reinforced concrete (RC) structures and steel structures are addressed in the seismic rehabilitation prestandard of the Federal Emergency Management Agency (FEMA 356). However, directly measuring the structural displacement is very difficult in most field applications and, alternatively, accelerometers are generally deployed to collect the structural responses instead of using displacement meters for building seismic monitoring. During the past decade, different techniques have been developed to provide displacement estimation using acceleration measurements but the conventional integration scheme relies on baseline correction methods to have a reasonable result and none of these techniques can properly estimate the residual displacement. In this study, the techniques of singular spectrum analysis (SSA) and the integration scheme are combined to estimate the displacement directly from the recorded acceleration. In the proposed method, SSA decomposes the acceleration measurement into approximation and detailed parts; the approximation parts are used as weighting factors, and the detailed parts are integrated twice to have the temporary displacements. Then, the displacement waveform can be correctly reproduced by fusing these two parts. Moreover, the proposed method is verified by using the roof responses of the RC specimen recorded during the shaking table test. The displacement waveform is correctly estimated as well as the induced permanent deformation during earthquake excitation. Last of all, a conclusion is briefly drawn and the applicability of the proposed method to building seismic monitoring is described.