Determination of Optimum Design Parameters of Non-linear Damped Outrigger System for High-rise Buildings

In addition to the inherent advantages of an outrigger system over conventional framed structural system, damped-outrigger systems (DOS) enhance it further with its agility to resist lateral loads in high-rise buildings. Dynamic response of slender and flexible buildings with DOS induces vibration control in which twisting of core structure is restricted by shear deformation of the damper present at the end of outrigger connected by perimeter columns. In this paper, a 300 m tall core-tube type steel building is modelled and analysed using ETABS based on GB 50011-2010 with singly viscous-damped outrigger system and its predefined optimum location obtained from literature as 240 m (from the base storey). After validation, 25 models are created for parametric studies by increasing number of DOS, changing level of DOS, changing the stiffness of outrigger and elastic properties of non-linear fluid viscous damper (FVD), pall friction damper (PFD), buckling restrained braces (BRB), viscoelastic, improved viscous damper (IVD) including damping coefficient, exponent of damping and effective stiffness. Optimum locations of different outrigger system and adequate properties with respect to supplemental damping devices are determined by carrying out time history analysis for maximization of building stability against high seismic excitation. The maximum response of the building, economic analysis of materials and available space for free planning are used to define two factors, viz., cost-effective response factor (CERF) and overall efficiency factor (OEF) based on which the different models are compared.