Wind Tunnel Studies on Sawtooth and Monosloped Roofs

Wind tunnel studies were conducted on 1:100 scale building models of monosloped and several (two- through five-span) sawtooth roof buildings to determine appropriate peak and area-averaged wind pressure coefficients. The results showed that the peak negative pressure coefficients in the high corner regions of monosloped roof buildings are nearly equal to the high corner peak negative pressure coefficients on the windward span (Span A) of the sawtooth roof building, and as expected, low corner zone peak negative pressure coefficients on sawtooth roofs are greater (approximately 150%) than on monosloped roofs. The peak negative coefficients were in general agreement with the earlier wind tunnel study used to develop American wind load design standards, and they suggested that the Australian wind design standard may underestimate the peak loads for moderately sloped (around 20 degrees) sawtooth roofs. Preliminary analyses of the data suggest that current ASCE 7 wind design provisions for monosloped roof buildings may underestimate the high corner design wind pressure. However, this may be offset by a more rapid decrease in area-averaged peak pressure coefficients with increasing tributary areas than was previously observed in the earlier studies.