Modeling of structural coupling for assessment of modal properties of twin tall buildings with a skybridge

This paper describes analytical modeling of structural coupling for generic twin buildings with a skybridge. The structural coupling of the interconnected buildings is modeled by introducing a six-degree-of-freedom model lumped at the skybridge level. The equations of motion of the reduced system are derived. In free vibration analysis, the natural frequencies and modal shapes are obtained for various levels of the relative stiffness of the inter-building beam representing the skybridge. Dependence of the calculated natural frequencies and modes of vibration on the skybridge stiffness is investigated. The empirical formulas to describe these quantities are proposed for preliminary design of twin buildings with structural coupling.