Seismic Response Analysis of High-Rise Reinforced Concrete Buildings Using Outrigger System

For the past few years, the trend of construction of high-rise buildings has progressed due to rapid urbanization and lack of land for horizontal expansion, especially in metropolis. These buildings are uniquely characterized by the requirement of major design consideration under lateral loads, earthquakes, or wind. So, it becomes more difficult to control the drift and deflection with the increasing height of the structure. To this end, this study presents a few energy-dissipating techniques that can be used in buildings to increase their stiffness and stability under seismic forces, along with a comparative analysis of the appropriate system to dissipate the maximum energy induced by these forces. A total of one hundred twenty-three analytical models were created on finite element modeling software using two sets of models. The linear dynamic analysis was carried out in the reference building and building with three different outrigger systems. The best outrigger system was selected, and its optimum location was determined by comparing their results in terms of story drift and top story deflection. The seismic response analysis of the first set of models illustrates that the M3 system with belt truss and cap truss is the best outrigger system, and its position is nearly at the mid-height of the building. Furthermore, the research was extended to the second set of models with ten more different systems with varying numbers of stories to investigate the effect of the slenderness ratio to locate the optimum position of the outrigger. The study highlights that it is more effective to place the outrigger at the upper heights of the building with a lower slenderness ratio to control the lateral displacement. © 2023, The Institution of Engineers (India).