Rocking and overturning prevention for non-structural monolithic objects under seismic excitations through base isolation: a case study in Ferrara (ITALY)

This paper addresses the problem of earthquake protection of heavy non-structural monolithic objects usually placed on the top of historical masonry constructions for mainly decorative purposes. Such objects, when subjected to seismic actions, may undergo rocking phenomena which may eventually lead to the overturning of the whole body. Understanding the dynamical behavior of these systems under earthquake excitations is highly important in order to devise an effective protection strategy. In this paper it will be shown that base isolation can be a very promising technique which allows for an effective, low-invasive solution to the problem of seismic protection of nonstructural monolithic objects which is widely encountered when working in the field of seismic retrofit of historical constructions. With this purpose, the actual case study of base isolation of ancient marble pinnacles placed on the top of a three-arched masonry city gate in Ferrara (Italy) will be dealt with in details.