Dynamic characteristics of wind-excited linked twin buildings based on a 3-dimensional analytical model

• An analytical model for the linked building system is formed as a matrix formulation.
• Modal properties and wind-induced structural responses are computed using the model.
• The link could substantially alter the modal properties of the system.
• The link can substantially alter the wind-induced responses of the system.
• Caution should be exercised in the wind-resistant design of linked building systems.

The present work investigates the effects of structural links on the modal properties and wind-induced responses of a linked building system (LBS) by using an advanced three-dimensional analytical model. The LBS in this study refers to a system consisting of twin buildings horizontally connected by structural links such as skybridges and skygardens. The proposed analytical model of the LBS is derived by assembling the structural-property matrices of a rigid floor diaphragm model of the buildings and those of a beam model of each link. The accuracy of the analytical model is then compared with and validated by a detailed finite element method (FEM) model. By employing the analytical model together with the layer-by-layer wind force time histories measured in a wind tunnel, the modal properties and wind-induced dynamic responses are computed for LBSs with different link properties. The results show that the link can substantially alter the modal properties of the system, and hence the structural responses. In some cases, the wind-induced responses of LBSs are reduced in comparison with those of two independent towers (without a link), attributing to the additional link stiffness as mobilizing the stiffness of an individual tower to resist the lateral wind loads. In other cases, the structural responses are increased, due to the extra link mass and the lateral–torsional coupling induced by the link. Therefore, caution should be exercised in the wind-resistant design of a LBS, in particular in regard to the link properties, to avoid undesirable wind-induced responses.