Milad Jahangiri

With the increase in population, people are looking to build buildings with more height and floors than in the past, as a result, engineers will have to retrofit and improve structures with different heights in the not-so-distant future, and currently most of the regulations They suggest a damping ratio of 5% for all structures. On the other hand, to investigate the seismic behavior of structures, other dynamic parameters of the structure such as the dominant frequency of the structure (period of the structure) are also needed and should be accurately provided to engineers and researchers. One of the most reliable methods of determining dynamic parameters is the measurement of microearthquakes using field methods. In this thesis, dynamic parameters of buildings. It has been calculated and determined using micro-seismic sampling and floor spectral ratio (FSR) and random reduction (RDM) and functional modal analysis (OMA) methods and for different buildings in terms of height and floors and different structural systems such as Masonry, metal and concrete, are also compared in terms of age or different ages . The investigations carried out in this thesis show that the damping ratio decreases with the increase in the number of floors in buildings.