A BUILDING CLASSIFICATION SYSTEM FOR SEISMIC RISK ASSESSMENT OF GOSTIVAR, NORTH MACEDONIA

Strong earthquakes are among the natural hazards with most destructive potential to life and property. Their negative effects must be adequately addressed allowing the communities to withstand, respond and recover from seismic events. Common mitigation measures include enforcement of seismic codes, land-use planning and strengthening of the existing structures. The seismic risk assessment process of the existing buildings is therefore central for planning of the emergency response and short- and long-term mitigation efforts. North Macedonia is one of the seismically active regions in the Balkans, south-eastern Europe. Of major importance is the NE-SW seismotectonic zone extending a few hundred kilometres from Kjustendil (Bulgaria), via the capital Skopje to Vlorë (Albania), since it affects the most densely populated areas with about 60% of the total population. The city of Gostivar located in its central part, about 65 km SW from Skopje, was selected as the study area for the present research. With a population of more than 30,000 inhabitants, the urban area is characterized with a large portion of older buildings built before the introduction of the first seismic design code in 1964. Most of the recent building stock consists of residential buildings built of reinforced concrete. This paper focuses on the classification model for the existing building stock in Gostivar. It was developed collecting information from multiple sources, i.e. cadastre, municipal archives and rapid visual screening. The retained building classification scheme represents a combination of the exposure model for Skopje developed following the 1963 earthquake, Risk-EU project and GEM building taxonomy. The inventory encompasses more than 10.000 buildings and is characterized with several building attributes including coordinates, footprint, number of stories, structural material, load bearing system, code level, occupancy class. Particular attention was paid to the classification of the essential facilities such as hospitals, police and fire stations, and schools.