POD analysis of aerodynamic correlations and wind-induced responses of two tall linked buildings

This study investigates the aerodynamic characteristics and inter-building aerodynamic correlations of two tall linked buildings (LBs, i.e., tall buildings connected by horizontal structural links). Wind pressure data on typical LBs with different gap distances between the two buildings were used, and proper orthogonal decomposition (POD) analysis was then applied to identify POD modes (e.g., hidden pressure patterns in this study). The results show that the 1st POD mode is highly correlated with the along-wind forces with both small and large gap distances, owing to pressure fluctuations on the windward surfaces of the two buildings. Owing to vortex shedding, the 2nd POD mode with small gap distance and the 3rd POD mode with large gap distance are mainly associated with the cross-wind forces. The positive inter-building aerodynamic correlation of the along-wind force with a large gap distance is smaller than those with a small gap distance. On the contrary, the cross-wind forces do not show a similar relationship with the gap distance; in fact, their correlation is further complicated by interference. Wind-induced responses from the dominant POD modes were also investigated. When the aerodynamic correlation is negative, the link of the LB system contributes to a significant reduction in the responses. However, when the correlation is positive, the link has no effect on the responses. In addition, the effect of each POD mode on each structural mode using the cross-modal participation coefficients of the double modal transformation method is investigated. For each POD mode, when the wind loads were large, the cross-modal participation coefficients were also large.