Effect Of Vertical Irregularity On Fundamental Period And Stability Of Reinforced Concrete Building


Bereket Netsanet Bekele, Lecturer
Department of Civil Engineering, Wolaita Sodo University, Ethiopia.
Wudenesh Honja Angelo, Lecturer
Department of Civil Engineering, Wolaita Sodo University, Ethiopia.


Now a day, many building have not regular configuration both in plan and in elevation due to different functional and aesthetic requirements. Hence, the evaluation of the seismic behavior of reinforced concrete building with plan and elevation irregularity is required. In this study the evaluation of the effect setback irregularity on fundamental and stability of reinforced concrete. The standards used for analysis of base case building and vertical irregular building using response spectrum analysis (RSA) method are adopted according to the provision of ES EN 1998-1:2015. The evaluation of fundamental period and stability based on the value of sensitive inter-story drift were assessed in detail using seven different building. Story eight and Story twelve reinforced concrete building with different setback irregularity were selected and their responses were compared with the ones of a corresponding base case was done using ETABS 2016.1.0 software. The setback of building is formed by the abrupt reduction in different floor area along the height of the building. The fundamental period and stability of setback buildings was found to be significantly different from the base case building, according to the findings of this study. It was discovered that the fundamental period of rigidity irregular buildings is longer than that of equivalent regular buildings. The fundamental period of a setback structure is shorter than that of a comparable regular structure. The findings reveal that the seismic response variation of setback building from the base case is dependent not only on the size of the irregularity, but also on the placement of the irregularity.