Code Requirements for Isolated Buildings

Abstract

The first building in the USA to use a seismic isolation system was completed in 1985 and was publicized in national engineering magazines and visited by a great many engineers and architects from the USA and around the world. However, it was several years before the second base-isolated building was begun. The acceptance of isolation as an anti-seismic design approach for some classes of buildings has clearly been inhibited in the USA by lack of a code covering base-isolated structures. It was recognized quite early that it was necessary to add isolation design requirements to the existing structural codes and, accordingly, the Structural Engineers Association of Northern California (SEAONC) created a working group in 1980 to develop design guidelines for isolated buildings. A brief document was produced and became the starting point for a sub-committee of the SEAONC Seismology Committee that was formed in early 1985.