Variations of wind pressure on hip roofs with roof pitch

Abstract

Three hip roofed building models of 15°, 20°, and 30° roof pitch, respectively, are tested in a wind tunnel to investigate wind pressure distributions over hip roofs and the effect of roof pitch on roof pressures. The pressures measured on the hip roofs are then compared with those on gable roofs of otherwise similar geometry to evaluate the effect of roof shape on roof pressures. Finally, the measured roof pressures of commonly-used probability of occurrence are compared with Meecham's work in terms of local mean and peak pressures. The results show that roof pitch does affect both the magnitude and distribution of hip roof pressures. The 30° hip roof experiences the highest peak suction at roof corner among the three tested hip roofs. The worst peak suctions are much smaller on the hip roofs than on the gable roofs for 15° and 20° roof pitches. However, the worst peak suctions on the hip and gable roofs are almost the same for 30° roof pitch. It is also seen that the magnitudes and distributions of local mean and peak pressures on the low pitched hip roof tested here are compatible with the results from Meecham's work on a hip roof of similar geometry.