Vertical irregularities in high-rise buildings present unique challenges to structural performance under lateral forces like wind and seismic loads. These irregularities involve changes in mass, stiffness or geometry of structures and cause disturbance in forces and deformations, bringing stress concentrations and irregular displacement patterns. Such vulnerabilities cause high possibilities of structural failure depending on such regions as those that experience an earthquake frequently. The effects of vertical irregularities in high rise structural framework are examined comprehensively through computational simulations which have been verified with experimental analysis in this paper. The analysis focuses on three key types of irregularities: The first include mass discontinuities, stiffness variations and geometric setbacks. Calculation results show that mass irregularities greatly increase axial forces, bending moments, and shear stresses within the transition floors. Lateral load distribution disparities like soft story cause excessive inter story drift than required whereas geometric dispersions affect torsional responses and disrupts flow of displaced length. Related to this, the findings stress the importance of using performance-based design methods to respond to existing vertical gradient irregularities. Possible control measures are: massive strengthening of weak stories with shear walls, mass re-arrangement for balanced structure behavior, and increasing the torsional stiffness by better detailing and these findings provide valuable design guidelines for engineers and designers towards development of improved structures whose design withstands the exercise of the extreme events. In turn, this research aims to develop design concepts for higher structures and identify how to improve their safety and lifespan in cases of seismic activity.
Zain et al. (Sat,) studied this question.