Wind Pressures on 4∶12-Sloped Hip Roofs of L- and T-Shaped Low-Rise Buildings

Abstract

A comprehensive wind tunnel experimental study for 4∶12-sloped hip roofs of L- and T-shaped low buildings was carried out in a simulated open terrain exposure to examine wind load characteristics and assess the applicability of wind provisions specified by the American wind load standard for such geometries. Results show that considering roof shape effects, hip roofs with rectangular or complex plans perform differently from rectangular gable roofs and incur smaller local and area-averaged suction. For L- and T-shaped hip roofs, distinctive pressure distributions occur, particularly along roof eaves near building re-entrant corners, where considerable suction appears for the wind blowing toward these building re-entrant corners. Furthermore, the building length-to-width aspect ratio effects are in most cases moderate. Generally, the wind load provisions of the American wind load standard are adequate for L- and T-shaped hip roofs, except for the edge zone along ridge and hip with large areas, for which measured values exceed the code-specified wind pressure coefficients. Finally, it was found more appropriate to utilize the entire L- or T-shaped roof dimensions, as opposed to the rectangular section only, to determine the least horizontal dimension of such nonrectangular hip roofs for the definition of roof zones.