Reduced-basis stiffness inversion of a structure-foundation system via component-mode synthesis

The purpose of this paper is to propose a new formulation for incremental reduced-basis stiffness inversion via component-mode synthesis. An elastically supported shear building model is taken as an example of an assemblage of substructures. The superstructure, the swaying spring and the rocking spring are regarded as the constituent substructures. The story stiffnesses of the superstructure are expressed in terms of linear combinations of several stiffness basis distributions. Eigenmodes of a fixed-base shear beam model having a uniform cross-section combined with rigid modes due to swaying and rocking displacements of the foundation are adopted as component modes for an overall model. It is shown that inverse use of the component-mode synthesis technique in an incremental inverse problem enables the development of an efficient computational procedure for finding stiffness parameters in the design problem. An approximate expression for the seismic response to stationary random excitations is also presented for the reduced model. The validity of the proposed method is demonstrated through several elastically supported shear building models. Copyright (C) 2000 John Wiley & Sons, Ltd.