Loop substructure identification for shear structures of unknown structural mass using synthesized references

Abstract

Shear structure is widely adopted to model the dynamics for building structures. Thus, developing accurate and efficient parameter identification methods for a shear structure plays a crucial role in structural health monitoring for building structures. In the authors’ previous studies, a loop substructure identification (LSI) method was proposed for shear structures, in which the dynamic equation of a two-story substructure is utilized to establish a loop identification sequence, directly estimating the substructure’s parameters. To ensure the convergence of the loop identification sequence, some structural control (SC) systems are needed to change the critical structural responses in a favorable way. However, the limited availability of SC systems in general buildings restrains the wide application of this controlled loop substructure identification (CLSI) method. In this paper, the original LSI method is first reformed, which can perform the LSI even if the structural mass is unknown. Then, a new reference selection method is proposed to make the LSI method converge without the help of SC systems. Different synthesized reference responses, formed by a weighted linear combination of measured structural responses, are used to formulate the LSI sequence. Next, an optimization strategy is proposed to determine the optimal weighting factors of the synthesized reference responses, which makes the LSI converged. Finally, the LSI is carried out for a 20-story shear structure, the identification results of which show that the proposed LSI method, combined with the proposed reference selection method, can very accurately estimate the substructure parameters of the shear structure.