PROPOSAL OF SEISMIC SAFETY EVALUATION METHOD FOR SEISMICALLY ISOLATED BUILDINGS CONSIDERING REDUNDANCY FOR EARTHQUAKE GROUND MOTION LEVELS

Abstract

The occurrence of earthquake ground motions exceeding the assumed design level may lead to plasticization of the superstructure of seismically isolated buildings. It is known that the plasticization of the superstructure is accompanied by a rapid development of deformation (quasi-brittle). In this paper, the relationship between the Ds value and the ductility factor is determined using incremental dynamic analysis, and the nature of quasi-brittle is quantified by formulating this relationship. Furthermore, seismic safety evaluation method for the limit state of seismic isolation layer and superstructure in seismically isolated buildings is proposed using this relationship.