NCEER-93-0004 | 3/23/1993 | 210 pages
TOC: The table of contents is provided.
Keywords: Corner Displacement, Base Isolated Structures, Design Codes, Nonlinear Time History Analysis, Uniform Building Code (UBC) 1991 Edition, SEAOC Recommended Lateral Force Requirements 1990 Edition, Analytical Methods, Code Provisions, Static Analysis, Response Spectrum Analysis, Correlation Studies, Center Displacement, Experimental Evaluation, Nonlinear Dynamic Analysis, Story Shear, and Interstory Drift.
Abstract: The Structural Engineers Association of California (SEAOC) and the International Conference of Building Officials have adopted guidelines and regulations for the design of seismic-isolated structures. These guidelines and regulations specify procedures for the analysis and design of isolated structures. These procedures include a static analysis method for establishing minimum limits of design, and a dynamic analysis method which includes response spectrum and time history analysis methods. This report presents a comparison of results of the static and response spectrum analysis methods to results of nonlinear dynamic analysis for a class of seismic-isolated structures. The structures include 1-story (stiff) and 8-story (flexible) superstructures on stiff and medium soil sites and isolation systems described by twenty-two different generic nonlinear hysteretic models, which are representative of a wide range of elastomeric isolation systems. It is shown that when the response spectrum analysis procedure is properly applied, the static and response spectrum analysis procedures predict results which match the mean of time history results for the bearing displacements and shear forces at the base of the building. However, the static and response spectrum analysis procedures can significantly underpredict the shear force in the upper stories even for the case of low effective damping in the isolation system.