Wind-induced loading and dynamic responses of a row of tall buildings under strong interference

Abstract

This paper studies wind-induced interference effects on a row of five square-plan tall buildings arranged in close proximity. Mean and fluctuating wind loads are measured on each building member and wind-induced dynamic responses of the building are estimated with the high-frequency force-balance technique. The modifications of building responses from interference over a practical range of reduced velocities are represented by an envelope interference factor. Wind tunnel experiments and response analysis are carried out under all possible angles of wind incidence, at four different building separation distances, and for two arrangement patterns of buildings in the row, that is the parallel and diamond patterns. It is found that building interference leads to amplified dynamic responses in many cases but reduction in responses also occurs at some wind incidence. For a building row of the parallel pattern, five distinct wind incidence sectors of different levels and mechanisms of interference effect can be identified. The largest values of envelope interference factors can reach 2.4 for the torsional responses. When the row of tall buildings is arranged in the diamond pattern, increase in wind excitation occurs at many wind angles due to a “wind catchment” effect. The interference factors have larger peak values, reaching 2.1 in the sway directions and above 4 in torsion. However, all large amplifications of building responses do not occur in the situations of peak resonant dynamic responses of the single isolated building. Thus, the design values of peak dynamic responses of a tall building are not significantly magnified when placed in a row.