A Review on the Development of Outriggers and Introduction to Hybrid Outrigger System on Tall Buildings

The concept of outriggers as a lateral load resisting system in high-rise structures has been used since decades. The relevance of outriggers gains prominence due to its efficiency in restraining the rotations in core wall which in turn reduces its bending moment and lateral deflection of the structure. Studies related to the behaviour of outriggers on tall buildings have been undertaken by various researchers, and condensing the concept, mechanism and its behaviour is vital in providing a proper guidance to researchers. Even though researchers have worked on buildings with outriggers, literatures mentioning the analysis of both conventional and virtual outriggers in the same building which acts like a hybrid outrigger system were underexplored. Therefore, this article discusses a review on the background of outriggers, classification of outriggers, parameters influencing the outrigger behaviour and introduces the concept of hybrid outrigger system in high-rise RCC structures. The efficacy of conventional, virtual and hybrid outrigger system is compared by modelling a 30-storey RCC building in a finite element software, ETABS, for both static and dynamic loads. The results from the comparative study showed that hybrid outrigger system may be used as an efficient lateral load resisting system.