At the core of every project designed by structural engineers, lies the requirement that the structure has to maintain its integrity under different actions, among which the most specific is the seismic action. The Republic of North Macedonia is situated in region which is seismically very active, so we need to pay special attention to the seismic action and its influence on the behavior of reinforced concrete structural elements.

In this paper, parameter study and numerical analysis are performed by varying the seismic hazard of certain reinforced concrete building. According to the seismic zone map for our country, its territory is divided into five seismic zones. The variable parameter for each zone is the peak ground acceleration a_gR (PGA), which according to EN 1998-1 is used to define the seismic hazard. This parameter takes the following values: a_gR={0,1g; 0,15g; 0,2g; 0,25g; 0,3g}. By implementing an analysis for each of the listed values, it is realized how and to what extent the seismic hazard affects the behavior of reinforced concrete structural elements.

It is expected that by increasing the value of PGA, the design values of the effects of actions in beams and columns will also increase. As a consequence to that, the geometric reinforcement ratio increases, too. When PGA varies, the design values of bending moment in beams, and thus the reinforcement ratio increase by 2-3 times. At the column sections, this ratio reaches an increase of 40% when PGA varies.

Overall, it may be said that the seismic hazard has a huge impact on the structural elements and the behavior of the structure at all. Therefore, it is necessary to pay special attention when designing buildings that are located in seismically active areas.