Structural modeling and conservation of single columns in archaeological areas

Conflicts between conservation and safety assume in the archaeological areas a determinant role, since the constructions to be evaluated are ruins. In these areas safeguard of heritage, safeguard of tourists and exigencies of fruition cannot coincide. An emblematic case in the Pompeii site is the safeguard of isolated constructions made of superimposed rigid blocks, such as isolated columns, groups of columns connected with a trabeation, jambs made of grey tuff cutted blocks without connections with the walls behind. The original state of the elements is often compromised by cracks, out of plane configurations, material detach. Often the archaeological exigency is the preservation of the defects in order to record historical facts. Usually repairs are made by sealing the cracks with grout, reattaching of stone piece with mortar only or pins. The choice of the structural model to assess the seismic vulnerability of elements strongly influences the types of interventions, and this is a significant point in the case of Pompeii. In this paper the out of plane behaviour of superimposed masonry blocks is examined. A significant role is played by the material parameters, often difficult to evaluate. The safety assessment and the comparison with the conservation need can lead to different approach to the cultural heritage with respect to ordinary constructions