The paper describes the performance-based assessment procedure developed for masonry cultural heritage structures by PERPETUATE project (funded by the European Commission in the Seventh Framework Programme - www.perpetuate.eu). The three main points of this research programme are: 1) increasing of knowledge on the cultural assets and on the peculiar intensity measures of the seismic hazard; 2) improving of modelling strategies of the ground, the foundation system, the structure and the materials; 3) design of innovative, low-impact and reliable strengthening interventions. Final aim of the project is to develop European Guidelines for evaluation and mitigation of seismic risk to cultural heritage assets. 

In particular, in order to face these hard issues, the methodology proposed in PERPETUATE uses a displacement-based approach for the vulnerability evaluation and the design of interventions. According to recent trends in the field of seismic assessment, the use of safety verification in terms of displacement, rather than strength, orients to new strengthening techniques and helps in the comprehension of the interaction between structural elements and unmovable artistic assets. The procedure is based on the following fundamental steps: 1) definition of performance limit states, specific for the cultural heritage assets (considering both architectonic and artistic assets); 2) evaluation of the seismic hazard and of the soil-foundation interaction; 3) construction knowledge (historical analysis, survey, non-destructive testing, material parameters, structural identification); 4) development of structural models for the seismic analysis of masonry structures and artistic assets, in the actual state and for the design of interventions. The seismic performance assessment is evaluated in terms of the maximum Intensity Measure (selected as the most representative for the interpretation of the seismic response of the examined asset) value compatible with the given performance level examined: then, this IM value may be translated in the corresponding return period of the input demand.  This parameter becomes the crucial tool for planning the rehabilitation decisions. Two main scales are considered: a) the assessment of a single historic building or artistic asset; b) the evaluation of the seismic risk to cultural heritage assets in a wide territorial area, in order to plan mitigation strategies.

Within the project, the proposed procedure has been applied to different case studies that provide an exclusive occasion to face the problem of seismic protection of cultural heritage at different scales (single asset or group of buildings in town) and conditions (seismic prevention or reconstruction after an earthquake). Moreover in most of cases, relevant artistic assets are present, allowing us to test results provided by the project also for these “non structural” elements.