Wind loads on multi-span roof buildings

This paper examines wind loads acting on multi-span roofs of low-rise buildings by performing wind tunnel tests with models whose parameters are roof shape (sawtooth, gable), roof slope (5 degrees, 10 degrees, 20 degrees, 30 degrees, 45 degrees) and the number of spans (1-5). Large suctions can occur at either a high corner/edge or a low corner of sawtooth roofs, depending on roof slope and the location of roof span. Low corners of multi-span gable roofs experience large negative pressures on edge roofs of low-pitch roof slopes and on middle roofs of steeper roof slopes. Relatively large positive pressures on both sawtooth and multi-span gable roofs can occur at roof troughs of low-pitch roof slopes and their magnitude becomes larger as roof slope increases. For steeper roof slopes, large positive pressures are also observed at roof ridges of both roof shapes although their magnitude and the location of the roof span depend on roof shape. Both the size and the magnitude of suctions on walls between spans of sawtooth roofs increase with roof slope. Comparisons with ASCE7-16 design values were performed and the results imply that ASCE7-16 underestimates both positive and negative wind loads on most roof zones of multi-span roofs.

Automated summary

This study examines wind loads on multi-span roofs of low-rise buildings through wind tunnel tests. The results show that roof shape, roof slope, and the number of spans have significant influences on wind load distribution. The existing design standards underestimate the wind loads on most roof zones of multi-span roofs.