The Role of Belt Wall in Minimizing The Response Due To Wind Load

Outrigger is one of the tall building structural systems that are used to reduce the building responses due to the wind. Outrigger is a stiff beam that connects the core wall to exterior columns and this enables the vertical shear to be transferred from the core to the external columns, thereby forcing the perimeter columns to participate in carrying the overturning moment due to the wind. Belt wall is often added to a building with outrigger system to further reduce the displacement and acceleration of a tall building having an outrigger system. However, it is not known how effective the belt wall is in further reducing the building responses. Thus, 64 story reinforced concrete buildings are studied in order to determine how the belt wall improves the building responses due to the wind. Buildings with an outrigger system and buildings with a combination of the outrigger and belt wall system are analysed by a structural engineering software in order to determine the natural frequencies and eigenvectors in the along-wind, across-wind and torsional direction. The along-wind responses are determined by employing the procedures from the ASCE 7-16 while the across-wind responses of the buildings are calculated based on the procedures and wind tunnel data available in a database of aerodynamic load. Results from the analysis show that the belt wall reduces the along-wind and across-wind responses slightly. However, belt wall reduces the torsional acceleration of the buildings significantly, which otherwise cannot be reduced by the outrigger system