2nd Croatian Conference on Earthquake Engineering 2CroCEE

The response of structures exposed to earthquakes is mainly defined by the stiffness of the structural elements which is governed by their dimensions and the material properties. Building’s seismic performance is essential for their earthquake resilience especially beyond safety point defined by building code. The main philosophy of modern codes is to increase the earthquake resiliency of the buildings. Unfortunately, Macedonia is one of the last European countries were designing the structures is according to codes that are outdated. The older national seismic codes have not been modified in view of the implementation of the most recent knowledge. In this sense, there are no strict limits to prevent the design of rectangular columns with an unsuitable ratio of the section sides. Mainly, due to the need for greater open space and flat interior walls, the columns are designed as rectangular where the lower section side is oriented along a larger span. This results in decrease of the column capacity in that direction and also highly affects the global response of the structure under earthquake excitation. In order to investigate the influence of the ratio of section sides of a rectangular column on seismic performance of building structures, an existing RC frame structure was chosen for analysis. The results of the performed seismic assessment of the selected structure by nonlinear dynamic analysis, emphasize the importance of choosing square shape columns or rectangular columns with appropriate dimensions of the cross section even for low-rise buildings. Based on the analysis’ results, we conclude that designers need to pay more attention when choosing columns’ cross section dimensions in order to achieve an acceptable building resilience against earthquakes. The main finding underlines the need to use the new codes for building design in the territory of Macedonia.