The thesis addresses the building of the Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, with a focus on the assessment of the building’s fundamental vibration periods. In the first part of the thesis, the procedure for modeling the building structure is described, taking into account reinforced concrete elements and brick infills, which can significantly increase the stiffness of the building and, consequently, influence on the vibration periods. More specifically, the model used to represent brick infills according to the Eurocode 8 rules and to determine their characteristics is presented. The method for accounting for openings in the infills, which are modeled using an equivalent diagonal, is also described. In addition to the modeling, the basics of vibration period calculation using the Rayleigh method and the determination of design seismic forces are briefly summarized. The second part of the thesis presents the description and analysis of the building in three models, in which the influence of infills was gradually added. In the first model, brick infills were not considered; in the second model, only the parapets on the facade were included; and in the third model, all infills present in the building were taken into account. It was found that modeling the infills, as executed in the building, reduces the vibration period to 87 % and 73 % of the period in the X and Y directions of the model without infills. Therefore, the influence of infills should be considered in seismic analysis of buildings, otherwise seismic forces may be underestimated. Further research is needed to improve the modeling of buildings for the purpose of assessing seismic resilience.
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