effects of staircase on the seismic performance of reinforced concrete frame buildings considering the position of the staircase

due to importance of stairs performance making the possibility of leaving the building for residents, they play a vital role in the building and their seismic performance is so important and should be taken into consideration. in this paper, 2 series of analysis models have been made by etabs. in these series, relevant analysis has been made about the influence of stairs in 6-story building while it is near the middle of the structure and while it is near the corner of the structure. results from linear analysis show that in concrete structure, it is essential to consider the modeling of structure as it causes additional stiffness and change in coordinate of center of rigidity, in a way that its effects are significant while the position of staircase is far from center of rigidity of the structure not having the staircase. these effects can be evaluated in period, stiffness, torsional moment, columns force and displacement of the structure.