Performance assessment of vertically irregular low-rise and mid-rise reinforced concrete structures

Nowadays, the application of vertically irregular type of buildings gains a lot of interest in seismic research field. Many structures are designed with vertical irregularity, which are widely used to achieve architectural and/ or functional purposes. This study investigated the structural response of various regular and vertically irregular low-rise and mid-rise buildings. All reinforced concrete (RC) frame models considered had three and seven stories having four bays with a uniform bay width of 4 m and uniform story height of 3 m. As a vertical irregularity, stiffness/strength irregularity with missing beams or columns, mass irregularity, and vertical geometric irregularity (set-back) were studied. Each irregularity type composed of various cases. A total of two regular and thirty irregular frame models were examined through nonlinear pushover analysis. The capacity curve and plastic hinge formation in the structural members were determined for all models. In addition, the variation in the axial force of the columns of the RC frame buildings having the discontinuous column was evaluated. The analysis of the results showed that different types of structural irregularities had different types of influences on the case study structures.