Post-earthquake Resilience of a Room and Pillar Rock Cavity in Naples

The stability of ancient room and pillar cavities dug in seismic sites was modified by the occurrence of earthquakes during the time. In such complex systems, the seismic-induced modifications of resistances and loads may lead to local improvements of the condition under gravity loads. The paper proposes a probabilistic evaluation of such effect, in the frame of the performance based seismic assessment. The procedure was applied to evaluate the safety and the resilience of a room and pillar cavity dug in a rocky hill in Naples, known as Fontanelle cemetery, after the maximum credible earthquake. Non-linear dynamic analyses were performed on a refined 3D model calibrated on the available experimental data. The safety of pillars and rooms was evaluated against two limit states, defined as a function of the Ratio between the Capacity and the Demand, CDR. The CDR of room and pillars computed after the seismic analyses were compared to their values before earthquake to check the capability of the cavity components to face the earthquake-induced modifications of the static equilibrium and consequently evaluate their resilience.