Wind Turbulence and Load Sharing Effects on Ballasted Roof-Top Solar Arrays

• Published in: Advances in Hurricane Engineering pp. 448 - 459
• Main Authors: Gamble, Scott, Browne, Matthew, Gibbons, Michael
• Format: Book Chapter
• Language: English
• Published: American Society of Civil Engineers (ASCE) 2013
• Subjects: Civil Engineering & Construction Materials; Structural Engineering; Roofs; Solar power; Turbulence; Commercial buildings; Wind loads
• ISBN: 0784412626; 9780784412626
• DOI: 10.1061/9780784412626.039

Solar arrays installed on roofs of low-rise commercial buildings are especially popular since it makes good use of previously unexploited real estate. These systems are usually restrained to resist wind-induced lift-off and sliding using ballast, penetrations, adhesives, or combinations thereof. In the case of ballasted systems, reducing the added weight on the roof is often the primary objective of designers, while maintaining a certain level of reliability. This can be accomplished through aerodynamic design and other methods, but sometimes more simply through the utilization of load sharing between adjacent panels. This is accomplished through the vertical bending stiffness of the racking system. This paper presents a discussion of the varied wind tunnel testing and analysis methods currently employed around the world, with a focus on the correlation effects associated with load sharing. A finite element model, in conjunction with wind tunnel data on a roof-top array, is used to demonstrate the impact of array stiffness on wind loads in a time- and spatially-varying sense. Practical guidance to determine ballast requirements is also provided.