Seismic Pounding Analysis of Palazzotto Borbonico “Vecchio” and “Nuovo” in Naples

Recent investigations of past earthquake damages in Italy highlighted the importance of assessing the seismic pounding between adjacent buildings. The problem of the safety verification of adjacent buildings is becoming extremely relevant as pounding effects may be highly destructive. The seismic vulnerability connected to this phenomenon is usually increased when the adjacent buildings present different construction materials and were realized before building codes prescribed a minimum size for separation joints in seismic areas. The case study which is here discussed refers to the city of Naples, Italy, a seismically active site, and to a couple of buildings which were built in different centuries and present different structural materials, i.e., masonry and timber for the historical one, called “Palazzotto Borbonico Vecchio”, and reinforced concrete for the modern one, “Palazzotto Nuovo”. Such buildings constitute two independent dynamic units, as it is clearly shown by the separation joint which was spontaneously generated along the bearing masonry wall that they share. The structures have been analyzed by means of three Finite Element models, both individually and joined; the global F.E.M. allows to consider the non-linear effect due to the buildings collision. Several linear and non-linear dynamic analyses have been performed in order to investigate the correct separation distance required for avoiding the pounding phenomenon, and the effects of pounding, varying parametrically the gap distance and the stiffness of the link elements.