Internal Pressures and Cladding Net Wind Loads on Full-Scale Low-Rise Building

Abstract

Wind-induced internal pressures have been measured at the Wind Engineering Research Field Laboratory full-scale low-rise test building at Texas Tech University, Lubbock, Tex., and compared with theoretical analysis. The pressure inside the building was controlled by the external pressure distribution, position and size of openings, volume of the building, and the flexibility of the envelope. The mean and fluctuating internal pressures in the nominally sealed building were smaller than the pressures on the external surfaces, and they increase with increasing windward/leeward open area ratio. Internal pressure resonance occurs close to the Helmholtz frequency in the building with a dominant opening. Effects of the flexibility of the envelope on the internal pressure fluctuations were accounted for by increasing the volume of the building by a factor of the bulk modulus of air KA to the bulk modulus of the building KB. External pressures on selected parts of the building and measured internal pressures were combined to study the characteristics of the net pressures acting on cladding elements, and they were compared with data derived from the AS1170.2 wind load standard. AS1170.2 generally provides satisfactory net pressure estimates for design of cladding on a nominally sealed building but can underestimate net cladding design pressures on some small tributary areas of a building with a dominant windward wall opening.