Development and Validation of a Seismic Isolation System for Lightweight Residential Construction

Keywords: Seismic isolation, residential construction, single concave rolling isolator, deformable rolling ball, displacement restraint, collapse performance.

Abstract: This report presents a study for the development of a practical low-cost seismic isolation system for lightweight residential construction. The study concludes that single concave rolling isolators cast in high strength concrete with a steel-reinforced plastic rolling ball and a displacement restraint system represent a promising isolation system.  A full size isolator suitable for application to typical reinforced concrete houses in Turkey was built and tested. The vertical stiffness, creep characteristics under gravity load and the lateral force-displacement characteristics have been studied. Models for behavior have been developed and validated. These models are useful for response history analysis in commonly available commercial and open source analysis software. A procedure was developed for designing reinforced concrete houses in Turkey equipped with the developed isolator. The validity of the design procedure was investigated in a study of the seismic collapse performance of two-story houses in Turkey following the procedures of FEMA P695. It was shown that houses in Turkey designed by this procedure and equipped with the developed isolation system have acceptable collapse risk, whereas comparable non-isolated houses do not.