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A significant number of masonry buildings, built prior to existing seismic codes, nowadays are used and serve a function as public institutions, namely schools, administration offices, courts, museums, theatres, etc. The necessity for evaluation of the seismic risk of these existing buildings is of high priority. In the framework of the research project SeismoWall, sixteen representative masonry buildings were selected and studied. The investigated buildings with their architectural layout, structural system and materials are typical for the buildings built between the end of the nineteenth and the beginning of twentieth century, not only in the country, but in the wider region of the Balkan Peninsula. The research activities in the project are divided in four main work packages: WP1-Selection of representative buildings and their static and seismic analysis, WP2-Experimental analysis of the mechanical properties of constituent components of the buildings and ambient vibration testing (AVT), WP3-correlation of numerical and experimental data and calibration of the dynamic characteristics of the buildings with the results from AVT and WP4-Determination of vulnerability curves for the selected masonry buildings. The main aim of the project SesimoWall is to define a series of seismic vulnerability curves for four classes of masonry buildings (unreinforced masonry with rigid/flexible floors, regular/irregular plan layout) for five geographical regions in Republic of North Macedonia with distinctive severe seismic hazard.

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Seismic vulnerability estimation of existing structures is unquestionably interesting topic of high priority, particularly after earthquake events. Having in mind the vast number of old masonry buildings in North Macedonia serving as public institutions, it is evident that the structural assessment of these buildings is an issue of great importance. In this paper, a comprehensive methodology for the development of seismic fragility curves of existing masonry buildings is presented. A scenario -based method that incorporates the knowledge of the tectonic style of the considered region, the active fault characterization, the earth crust model and the historical seismicity (determined via the Neo Deterministic approach) is used for calculation of the necessary response spectra. The capacity of the investigated masonry buildings has been determined by using nonlinear static analysis. MINEA software (SDA Engineering) is used for verification of the structural safety of the structures Performance point, obtained from the intersection of the capacity of the building and the spectra used, is selected as a response parameter. The thresholds of the spectral displacement are obtained by splitting the capacity curve into five parts, utilizing empirical formulas which are represented as a function of yield displacement and ultimate displacement. As a result, four levels of damage limit states are determined. A maximum likelihood estimation procedure for the process of fragility curves determination is noted as a final step in the proposed procedure. As a result, region specific series of vulnerability curves for structures are defined.

In this paper, a scenario-based neodeterministic approach for seismic hazard assessment (NDSHA) giving a realistic description of the seismic ground motion due to an earthquake of a given distance and magnitude is applied to the territory of North Macedonia and the hazard maps are obtained. A comprehensive understanding of both the seismic source process and the propagation of seismic waves is a prerequisite in the process of the application of NDSA on a specific region. The procedure is based on the integration of the existing geological, seismotectonic and geotechnical databases relevant to the selected region. In the definition of scenario earthquakes, the available seismic data, as well as information for the geological active faults in North Macedonia are used. This multi scenario-based analysis simultaneously incorporates the known databases and with use of advanced physical modeling techniques provides the required ground motion data set.The results are based on the computation of realistic synthetic seismogram. A reliable hazard map at regional scale, for the complete territory of North Macedonia are shown.As a final result, Maximum Credible Seismic Input -MCSI is computed for various locations in North Macedonia and valuable response specrta for the selected locations are obtained. These data (spectra and time histories) are set to be used as seismic input for the nonlinear analysis of the existing structures in North Macedonia in the process of seismic risk analysis on a regional scale.