Wind loads on roof-mounted equipment on low-rise buildings with low-slope roofs

Abstract

Damage surveys have indicated that roof-mounted equipment has significant vulnerability to extreme windstorms. The study investigates anchorage and envelope wind loads on 1:50 scale, roof-mounted equipment. Cubes with equivalent full-scale side lengths of 0.9 ​m, 3 ​m, and 4.6 ​m, and a rectangular prism with dimensions of 6 ​× ​3 ​× ​1.5 ​m (length ​× ​width ​× ​height) are examined. Experiments were conducted with this equipment placed at four different locations, which represent the roof corner, perimeter, and field regions. Additionally, the equipment was also tested when flush-mounted and elevated to 1.5 ​m, 3 ​m, and 4.6 ​m above the roof surface. It is found that wind loads relevant for anchorage design are a function of the size of the equipment, elevation above the roof, and roof location. The uplift wind loads for anchorage design of flush-mounted and elevated equipment are different, irrespective of the equipment size because of the exposed bottom surface for elevated equipment. However, the elevation effect on drag wind loads for anchorage design is negligible. The envelope wind loads are distinct from both the anchorage loads and the cladding loads on bare-roofed, low-rise buildings due to differences in the associated local aerodynamics.