Strutture voltate e terremoto: l’esempio di Ischia

Recent seismic events revealed the vulnerability of heritage buildings, and curved elements (arches, vaults and domes) add further vulnerability to those buildings. The internal thrust increases yielding to the out-of-plane mechanisms of the supporting masonry walls when curved elements are subjected to dynamic actions. This effect is strongly influenced by the shape and type of elements. For single curvature elements (arch, barrel vault), a kinematic failure mode can occur not involving the supporting structure. The collapse of more complex structures (e.g. domes) is generally related to out-of-plane mechanisms of the supports. Simplified approaches for dome assessment provide barely the cracking conditions. Key aspects on structural behavior of domes and effects of recent Casamicciola earthquake in 2017 (Ischia, Italy), confirming them, are discussed by means of a case study.