Analytical Behavior of Optimum Position of Multi-level Outriggers in RCC Frames

Abstract

This research aims to determine the optimum position of single-level, double-level, and multi-level outriggers for 10, 15, and 20 stories at 30, 45, and 60 m in height, respectively. A network of connected shear walls is often used to provide resistance against the lateral stresses that are caused by wind or earthquakes in tall structures. Nevertheless, as structures become higher, lateral stiffness becomes more of a worry; to address this issue, an outrigger may be added between the central core and the outside columns. When the structure is exposed to lateral forces, which would normally cause the core to rotate and result in excessive lateral deflection and the base moment, the outrigger helps to reduce the effects of both of these phenomena. Both symmetrical and asymmetrical outrigger provisions are taken into consideration while designing for the static and seismic stresses, respectively. The structural system is analyzed in 2 dimensions because, when bent in plane, it acts like a vertical cantilever. The values of lateral deflection, lateral drift, and base shear are measured in order to provide an evaluation of performance. The optimum position of a single-level outrigger is H/2, H/2.5, and H/2.85 from the top at 30, 45, and 60 m, respectively. For a two-level outrigger, the optimum position of the second outrigger is H/1, H/1.25, and H/1.4 at 30, 45, and 60 m, respectively (H-height of the building). Key findings from the research on the outrigger system's impact are tabulated and illustrated. The standardized software program ETABS 2019 was utilized for the analysis process.