STUDIES ON SEISMIC ISOLATION OF BUILDINGS

This paper has studied the applicability of base isolation to structures. The Navy is evaluating the potential use of base isolation for essential structures that must remain functional in a postearthquake environment. The paper reviews preliminary building-selection criteria and structural design criteria. For low-rise regular-frame construction situated on a rock or stiff site and housing-sensitive equipment, base isolation of the columns offers the potential for significant damage reduction. The paper presents a comparison of analysis techniques treating the isolator as a nonlinear hysteretic element and as linear elements with and without nodal damping. The results indicate that for the case studied, significant differences in displacement and drift result while moments vary by about 10%. Vertical acceleration effects were found to cause an increase in maximum moment by about 15%.