Behavioral Study of R.C. Structures Using Hybrid Outrigger System Under Seismic Loads

The prompt expansions of materials, construction technologies and structural systems have given upsurge to a substantial increase of skyscrapers over the previous decades. The reduction of the top drifts and base core overturning moments under lateral loads, such as earthquakes and wind loads, has drawn accumulative care in the structural design of tall buildings. When building height increases, the structure should have a lateral load resisting systems other than shear walls for evading the effect of lateral loads, since the shear walls when used alone are appropriate only up to 20 storied building. To overawed this encounter, the outrigger system has developed as a substitute solution, providing adequate lateral stiffness beyond the competencies of shear walls and bracing systems. Outrigger systems are one such protruding system and are deliberated to be the most prevalent and effectual because they are at ease to build and afford better lateral stiffness. The principle of using an outrigger system to develop the structural lateral stiffness and overall stability by connecting core tube and external columns through rigid horizontal cantilevers. Contingent on the connectivity between the core and the exterior columns, the outrigger system can be divided into virtual outrigger system and conventional outrigger system. The hybrid outrigger system has one conventional outrigger and one virtual outrigger at two distinct floor levels. Optimal locations for installations of outrigger systems can be originated. A concept of Virtual Outrigger is reviewed and evaluated in this study. Prominence is given to employing the Hybrid Outriggers instead of Conventional ones. Overall displacements and lateral drift can be reduced by conventional outrigger system for such heights. Outrigger systems enrich the stiffness of high-rise buildings by the introduction of rigid outriggers at different locations. The loads deliberated are as per IS codes. An ETABS model of buildings with varying heights are considered for this study.