Base isolation systems for earthquake protection of multi-storey shear structures

This paper is a study of the effectiveness of a wide range of bilinear hysteretic isolation systems in shielding multistorey 2-D shear structures from earthquake excitations. Important parameters of the isolation system are identified and their effect on structure response noted. It is shown that isolation systems can be constructed which allow the structure proper to remain purely elastic even during very strong ground motions. It is further shown that the shear responses and base displacements of structures on these isolation systems can be accurately estimated from elastic response spectra of the forcing earthquakes. The philosophy of structure isolation is discussed and an introduction given to the physical devices currently available to provide it.