The seismic assessment and retrofit of existing buildings is one of the main topics in the world of constructions due to progressive relative reduction of new construction activity with respect to interventions on existing structures, but the complexity of the topic constitutes a great obstacle to a strict codification of methodologies and approaches.

The first chapter deals with general consideration on the current norms for interventions on masonry building. More specifically a comparison between the Eurocode and the Italian Standards is proposed, highlighting several issues in which the Italian norms felt the necessity to introduce more articulation with respect to the relevant European norm.

Chapter 2 presents linear and non-linear analysis performed on a half scaled building specimen tested at the shaking table of the Laboratory of Earthquake Engineering of NTUA. The analyses of the building were carried out using three different models developed with well-known FEM programs. Through comparison between the experimentally extracted and the calculated modal properties, the accuracy of the FEM models was assessed and non-linear pushover analysis was performed.

Chapter 3 deals with the assessment and retrofit of a three story residential masonry building. Extended in-situ testing and investigations were carried out in order to evaluate the mechanical properties of the materials and the quality of the construction details. Linear and non-linear analyses were performed both at the initial state of the building and after the strengthening interventions. A comparison between the two methods of analyses is proposed and discussed.

chapter 4 offers a detailed report of the flat jack tests performed in the building analysed in chapter 3. The procedure of execution and the results of single flat jack test and double flat jack test are presented.

The structural evaluation of a historic orthodox church is the topic of chapter 5. Based on the results of in-situ testing and modal response spectrum analysis previously carried out on the church, the chapter deals with a local non-linear analysis in order to evaluate the transversal seismic response of the church at the initial state and after the proposed strengthening interventions. The methods used for the structural modelling and the results of the analyses are presented.