Full Session with Abstracts
Elevated buildings, such as those on stilts or piers, have found a common use particularly in coastal regions for the avoidance of waters from flooding, and potential reduction in hydrodynamic loading due to storm surge during high wind events (such as hurricanes) or otherwise. Though these raised structures are typically well-designed for the expected hydrodynamic lateral loading from flooding waters and carried debris, there are no provisions in ASCE 7 pertaining to wind loading on elevated structures. The air gap beneath the building as well as the exposure of its underside to wind flow alters the aerodynamics of the structure, creating the potential for modified structural response. Current provisions do not have adequate guidance for the aerodynamic loading on an elevated building. Given that residential homes located in storm-prone regions are already exposed to hazards of a significant level, the proper understanding of the consequences of raising a building and their necessary considerations in design is paramount.
An experimental program was conducted at the Florida International University Wall of Wind Experimental Facility using a scaled model of a single-story residential home elevated to various heights, including no elevation as the base condition, and scaled stilt heights modeling 2 feet, 7 feet, and 12 feet of elevation. Wind pressures on the surfaces of the model were measured for a range of wind directions. Analyses of peak pressure coefficients were performed to evaluate the effect of building elevation. First, pressure coefficients were compared between differing levels of building elevations, including underside floor pressures which are unique to elevated buildings. Second, a comparison of wall and roof pressure coefficients for each elevated case was made with those coefficients determined using ASCE 7-16 for non-elevated structures of an equivalent mean roof height. The results of this experimental program are used to provide recommendations for updating conventional wind load design provisions to improve the quality and durability of elevated residential homes.