CFD-Based Evaluation of Elevated Coastal Residential Buildings under Hurricane Wind Loads

Abstract

Many elevated houses in coastal areas have suffered serious wind-induced damage during hurricanes; this indicates the need for better understanding of the performance of elevated homes subjected to higher wind forces or effects in open pile-supported areas. The actual direct and indirect wind-induced damage to elevated wooden residential houses in past hurricanes is briefly reviewed. Computational fluid dynamics (CFD) analysis was utilized to investigate the effect of wind angle and house elevation on the magnitude of mean negative or positive design pressures as an important variable affecting the vulnerability of the structural system. The numerical results were validated based on available experimental tests in terms of the mean pressure coefficient (Cp) over the house surfaces. The CFD results show that elevating a house can result in increased wind speed and subsequent additional turbulence effects around the house, in particular at the exposed underside. The results indicate that elevating a house does not significantly affect the Cp distribution on the roof surfaces, so that the roof uplift forces remain almost constant. However, elevating the house leads to increases in Cp at various rates over the house surfaces, including exterior walls and along the underside. The rates of such increases depend on wind direction and house elevation. Regardless of wind direction, the overturning moment acting on an elevated 1:20 scale house increases about 50% and 95%, respectively, for 0.105 and 0.21 m elevations. Considering the scope and the limitation of the study presented in this paper, more studies are needed to better understand the effect of aerodynamic characteristics of elevated houses, particularly on peak positive or negative pressures over various building surfaces.