NEHRP Clearinghouse

Title
Feasibility Evaluation of Base Isolation for the Aseismic Design of Structures.
File
PB84186717.pdf
Author(s)
Vaidya, N. R.; Eggenberger, A. J.
Source
National Science Foundation, Washington, DC., January 1984, 130 p.
Abstract
The development of base isolation for use in seismic protection of building structures is examined and the base-isolated design philosophy is discussed. The shape, size, and number of bearings used to isolate a structure are evaluated in terms of the structure's aseismic design requirements. The equations of motion for structures of base-isolation bearings are described, along with procedures for the step-by-step integration of the nonlinear equations of motion. Three case studies are presented to illustrate the base-isolated response of structures. It is concluded that base isolation is most effective in reducing seismic forces on rigid structures, with fundamental frequencies in the range of about 3 to 10 Hz. It is recommended that variability of building material properties and the dynamic characteristics of the building be included in a probabilistic analysis to develop risk assessment for base-isolated designs.
Keywords
Dynamic response; Ground motion; Buildings; Bearings; Earthquake engineering; Earthquake resistant structures; Base isolation; Seismic design; Elastomers; Design criteria; Mathematical models; Seismic waves