LOCAL WIND LOADING ON THE ROOF OF A LOW-RISE BUILDING

Fundamental studies of wind loading on the roof of a 1:25 geometrical scale model of the Texas Tech University test building were performed in a boundary-layer wind tunnel. The investigation was focused on the pressure distribution in the windward corner region of the roof. A range of wind directions and roof parapet heights was considered. The surface flow patterns were visualized and compared with the roof pressure. The largest negative mean and peak pressure coefficients were found for cornering winds, wind direction of 235-degrees. The pressure coefficients obtained using the dynamic pressure at the roof height were, respectively, -3.5 and -11. Very low roof parapets increased the overall maximum roof suction, while high parapets decreased it. For the wind direction of 225-degrees, the highest negative pressure occurred in the secondary vortex region and the highest pressure gradient occurred in the reattachment region. It was found that the fluctuating roof pressure was sensitive to the intensity and the integral scale of turbulence in the oncoming flow. Comparison of the wind tunnel data with field data showed that the mean and the positive peak pressures were in good agreement. The negative peak pressures measured in the wind tunnel underestimated the field data.