Component and Cladding Wind Loads for Low-Slope Roofs on Low-Rise Buildings

The component and cladding wind load provisions for low-sloped roofs on low-rise buildings in ASCE 7-10 were examined using measured pressure data from an aerodynamic database. It was found that both the design pressure coefficients and size of the roof zones in ASCE 7-10 are much smaller in magnitude than indicated by the data. The data indicate that building height is the most significant parameter affecting the size of the roof zones, while plan dimensions have a limited impact on this class of buildings. Recommendations for revised roof zones are developed, which include a modification to the shape of the corner zone, the addition of a new interior zone far from the roof edges, and a zone size definition that depends only on building height. However, even with increased roof zone sizes, the measured data indicate that the design pressure coefficients must also be increased in the corners and edges.