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Nonlinear Dynamic Analysis of Three-Dimensional Base Isolated Structures (3D-BASIS)

S.Nagarajaiah, A.M.Reinhorn, M.C.Constantinou

NCEER-89-0019 | 8/3/1989 | 128 pages

About the Report:

TOC: The table of contents is provided.

Notes: This report is no longer available, however, the material has been updated in NCEER-94-0018.

Keywords: ign, Instantaneous Stiffness Formulation, Seismic Protection, Protective Systems, Base Isolation, Inelastic Behavior, Computer Programs, Dynamic Analysis, and 3D-BASIS.

Abstract: Base isolation for seismic protection has received considerable attention in the engineering community. Natural or synthetic rubber pads, Teflon bearings sliding on stainless steel, and combinations of displacement control and energy dissipation devices are used to reduce the energy input into building structures. This report describes the development of a comprehensive analytical model and a computer program, 3D-BASIS, for analysis of three-dimensional base isolated multistory buildings. Modeling various types of isolation devices with strong nonlinearities such as hysteretic and frictional devices or their combination is discussed. The superstructure, comprised of shear walls, frames and non-structural elements, is assumed to remain elastic. Comparison of response computed using 3D-BASIS with various existing programs and experimental results is considered. The hysteretic model considered in this report can reproduce bi-axial inelastic behavior of high damping rubber bearings with shear-stiffness degradation, steel dampers, viscoelastic dampers, bilinear behavior of lead-rubber bearings, and hysteretic behavior of friction interfaces effectively. The hysteretic behavior produced by this model compares well with available experimental results.