عنوان مقاله [English]
Based on Iranian Standard 2800, structures should be controlled for story drift after being designed for applied loads. In this phase, the base shear that causes the drift is determined based on one of these structural periods: 1-the proposed formula of the code (T1) 2-the analytical model of the structure (T2). To study the influence of the assumed period in the drift controlling phase, two similar 5-story buildings were designed. T1 and T2 have been used in the drift controlling phase of these two structures. Nonlinear time history analysis results show that the second structure has better seismic behavior, despite having a lower structural weight. Furthermore, a method is proposed here to find those elements that should be strengthened to satisfy the drift criteria. In slender tall buildings, some elements should be substituted by stronger ones in order to satisfy drift controlling criteria. There is not a standard method to find these elements, and they are normally found by engineering judgment or experience. To satisfy the drift criteria in some design offices, only the first story columns are changed. The obtained results of nonlinear time history analysis on 6 to 9 story slender buildings show that the proposed method of the present study is efficient in improving the seismic behavior of the buildings. However, changing only the first story columns worsens the seismic behavior of the buildings, despite satisfying the criteria.