Structural Analysis of Historical Constructions, New Delhi 2006 P.B. Lourenço, P. Roca, C. Modena, S. Agrawal (Eds.) 1 FOREWORD 1.1 Background The seismic assessment of existing structures can be considered a difficult task for several rea- sons. Research carried out in the last decades, following the 1976 Friuli and 1980 Irpinia earth- quakes, showed in fact that while in case of new constructions the behavioural models proposed by different international seismic codes, based on thorough analytical and experimental bases can be satisfactorily used, for what concerns buildings that belong to the cultural heritage the adoption of the same class of predictive models can be misleading with regards to the real re- sponse of the buildings. This is essentially due to the fact that existing constructions were built according to traditional rules that were far from the present day building process, and that the continuous modifications experienced by the building over the time produced several uncertain- ties in the model definition, besides the generally unsatisfactorily level of knowledge on the structural layout and on the mechanical properties of the constituting materials (Binda et al. 2005). At a European level (EC8, part 1.4) an attempt was made to define principles and general considerations that can take into account the diversity of the historical respect the new build- ings, even if the document seems not to be fully conscious of the particularities and preservation needs of such class of structures. Since 1986 (D.M. 24/01/1986) in Italy there was the introduc- tion of the concept of “seismic improvement” rather than seismic upgrading, that allowed, in case of minor interventions that did not alter in a significant manner the overall behaviour of the structure, to avoid the verification according to the standards prescriptions. Reasserted in 1996 (D.M. 16/01/1996), such concept was then connected to the assessment of cultural heritage buildings of monumental character, since it was considered compatible with their preservation exigencies. Codes of Practice for Architectural Heritage in Seismic Zones Claudio Modena University of Padua, Department of Structural and Transportation Engineering, Italy Filippo Casarin University of Padua, Department of Structural and Transportation Engineering, Italy Maria Rosa Valluzzi University of Padua, Department of Structural and Transportation Engineering, Italy Francesca da Porto University of Padua, Department of Structural and Transportation Engineering, Italy ABSTRACT: The acknowledgment from the scientific community that the buildings belonging to the cultural heritage can not be evaluated with regards to the seismic action according to stan- dards that are fitted for newly constructed buildings, indicated a new way to undertake in the seismic assessment of such class of buildings. In particular, it was accepted that the balance be- tween structural safety and architectural preservation must take into account both exigencies, on one hand not fully complying with the seismic actions defined by the standards if this would lead to interventions that can alter in a significant manner the cultural and architectonical es- sence of the building, on the other even changing the use of a specific building, in order to make it able to withstand the seismic action. Safety evaluations must then involve a multidisciplinary, qualitative/quantitative approach.