An Analysis of Outrigger Belt Truss System in High-Rise Buildings

Tall building development has been rapidly increasing worldwide, introducing new challenges that need to be met through engineering judgment. The outrigger-belt truss system is commonly used as one of the structural systems to effectively control the excessive drift due to lateral load (either wind or earthquake load) so that the risk of structural and non-structural damage can be minimized. For high-rise buildings, particularly in wind load dominant or seismic active zones, this system can be chosen as an appropriate structure. An effort has been made on the behavior of outrigger building models of 90 m height by performing lateral load analysis. In the analysis, different building models with two outriggers and buildings without outrigger are considered. The lateral load analysis is performed by subjecting the building models to the trapezoidal distribution of wind loads calculated by Gust factor method as per IS: 875 (Part 3)-1987. Thus, this paper aims at investigating and comparing various building models by varying the location of outriggers. A comparison of analysis results in terms of storey drift, core base moments and axial forces is presented. The results showed that using optimized multi-outriggers system can effectively reduce the deflection of the structure and increase the rigidity of the structure.