SEISMIC ASSESSMENT OF HISTORICAL NATURAL STONE MASONRY BUILDINGS THROUGH NON-LINEAR ANALYSIS

摘要

Seismic assessment of historical buildings is a complex problem due to the wide variety of involved aspects, such as the quality of masonry, the structural systems, the large effort in inspection and diagnosis, the economical and cultural implications.In the last years significant developments have occurred with respect to the possibilities of experimental and numerical analysis of ancient cultural heritage buildings. An example is the TREMURI program allows to obtain complete 3D macro-element models on which global non-linear static and dynamic analyses can be carried out, with limited computational efforts. By means of internal variables, the macro-element considers both the shear damage failure mode and its evolution, controlling the strength deterioration and the stiffness degradation, and rocking mechanisms, with toe crushing effect.In this paper the results of the experimental investigations and non-linear analyses on a historical building are shown. The analysed building is the St. Michele Arcangelo Monastery in Gragnano (Naples, Italy), that is a large Campanian natural stone masonry building with an internal cloister. Analyses were carried out, through laboratory tests and in-situ investigations; they underline critical issues related to the seismic response of historical buildings, such as the variability of traditional material properties, the different construction techniques, the limited knowledge on previous damage or the limitations in inspections and tests due to conservation issues for buildings of historical value. Finally several interesting considerations about various strengthening configurations are reported, in order to assess the effects of some common interventions on historical masonry buildings, considering both the global response and local collapse modes.