Seismic Analysis and Strengthening of Mallorca Cathedral

Abstract

Due to the complexity associated with the seismic action, as well as the dynamic properties of the structures, the design of historical buildings only took into account static actions. Depending on the seismicity of the site, the buildings are characterized by more or less constructive details adopted in order to prevent important damages due to seismic action. Therefore, the seismic analysis of Mallorca Cathedral is carried out in the present work. The typical damages arising from seismic activity in historical buildings are caused by single architectonic parts that are characterized by an autonomous structural behaviour than the rest of the building. These local mechanisms, which are likely to develop during an earthquake, are individualized with respect to Mallorca Cathedral within this thesis. The seismic analysis of Mallorca Cathedral comprises the individual analysis of each one of the considered local mechanisms. The nonlinear structural behaviour is obtained through limit analysis and the performance point is obtained though the capacity spectrum method. The results obtained for each local mechanism are its safety condition and, in the case of the safety being assured, the damage level that may be expected. A specific procedure developed for the analysis of historical structures that is recommended in the Italian code is used. The seismic demand of Mallorca Cathedral considered within this thesis corresponds to several spectrums obtained from the European and Spanish codes and the detailed seismic hazard evaluation of the cathedral carried out in a previous work. This evaluation comprised deterministic and probabilistic estimations of the seismic action that may be expected in the site. In order to reduce the damage level or to assure the safety of the local mechanisms, strengthening solutions are proposed in order to improve the seismic behaviour of Mallorca Cathedral. The mainprinciples and criteria for conservation and restoration of historical structures are respected.