Safety and reliability of structures including ductile and brittle elements

For many countries in seismic areas, the maintenance of the architectural heritage is nowadaysan essential priority. In Italy for example, the 90 % of the built up areas are more than 30 years old and the problem of the safety assessment and rehabilitation of the existing buildings is somehow crucial, due to the coming into force of a new generation seismic code adopting safety standards that are definitely higher than the previous. In this framework, the authors present a first analysis of the seismic reliability of a number oflow-rise ordinary masonry buildings, sorted with different geometrical and mechanical properties anddifferent ages. The analysis is then repeated by considering the main shear walls of the buildings strengthenedwith fiber reinforced polymers (FRP) reinforcements. Typically, masonry shear wall systems behavelike a low-ductility parallel systems, which exhibit a somewhat redundancy. When structural reinforcements with brittle behavior like FRP are introduced, the system ductility decreases together with the residual redundancy, and the reliability outcome does not increase as expected. The obtained results allow very interesting considerations on the reliability of the existing masonry structures andthe effectiveness of this strengthening technique when applied to masonry shear wall systems