Fixed and base isolation retrofitting of historic masonry buildings

Abstract

Traditionally, most historic buildings represent pre-21th century masonry structures. It is due to the extensive presence of such masonry structures that their behaviour under earthquakes will be analysed in this paper. First, this paper will outline the traditional methods and materials used in the construction of historic masonry structures. Second, a typical damage scenario will be described showing what happens when these historic structures are subjected to earthquakes. Reference will also be given to damage suffered by historic buildings under the latest catastrophic earthquakes in L'Aquilla, Haiti and Chile. The traditional, standard methods for repair are discussed. Then, the principles of the base isolation theory and the current hardware used for isolating structures is presented. Next, a time-history analysis of a historic masonry church is discussed, comparing the response of a fixed-base versus an isolated church. Finally, a review of the IZIIS' activities related to protection of historic buildings against earthquakes is given. It is concluded that base isolation is very applicable in retrofitting of historic buildings since it drastically reduces the seismic forces and enables protection of these structures by minimal interventions.