Conventional seismic design of earthquake-resistant structures is based on the philosophy conditions that the structural safety must be assured in extreme earthquake and the possible damage, if any, should be minimized or avoided in moderate earthquake ones. In the recent years the technique of seismic isolation appeared suitable to provide protection of buildings against seismic loadings introducing isolation devices (i.e. isolators) between the building itself and the foundation that may be adequate to shift the structures fundamental frequency outside the seismic characteristic range. The aim of this paper is to evaluate the influence of high damping rubber bearings, like the lead rubber ones, in the propagation of dynamic loading along NPP buildings. To this purpose a numerical approach was applied setting up suitable finite element models of the possible Generation III+ or IV NPPs. The influence of the isolator characteristics on the response of structures is analysed considering the variation of important parameters like the superstructure flexibility, isolation time period, etc. Several seismic analyses were therefore performed assuming as input different real earthquake ground motions as available in literature and in the relevant rules. The obtained results were herein presented and discussed in order to highlight the isolation technique effectiveness.
ANALYSIS OF SEISMIC ISOLATION PROBLEMS OF NPP BUILDINGS
LO FRANO, ROSA;FORASASSI, GIUSEPPE
2010-01-01
Abstract
Conventional seismic design of earthquake-resistant structures is based on the philosophy conditions that the structural safety must be assured in extreme earthquake and the possible damage, if any, should be minimized or avoided in moderate earthquake ones. In the recent years the technique of seismic isolation appeared suitable to provide protection of buildings against seismic loadings introducing isolation devices (i.e. isolators) between the building itself and the foundation that may be adequate to shift the structures fundamental frequency outside the seismic characteristic range. The aim of this paper is to evaluate the influence of high damping rubber bearings, like the lead rubber ones, in the propagation of dynamic loading along NPP buildings. To this purpose a numerical approach was applied setting up suitable finite element models of the possible Generation III+ or IV NPPs. The influence of the isolator characteristics on the response of structures is analysed considering the variation of important parameters like the superstructure flexibility, isolation time period, etc. Several seismic analyses were therefore performed assuming as input different real earthquake ground motions as available in literature and in the relevant rules. The obtained results were herein presented and discussed in order to highlight the isolation technique effectiveness.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
