Computational Analysis of Current and Future Wind Resilience of Residential Roofs Across Florida and Bermuda

Abstract

With climate change drastically altering historical meteorological trends, especially hurricanes, the study of structural wind resilience has become a topic of increasing importance. 50 years ago, wind loads were not even mentioned in ASCE codes for structural design. But now, with the prediction of hurricane intensity increasing, it is pertinent that accurate wind loading is used when designing buildings. This holds especially true for residential structures, as the home is where most people shelter in times of tropical cyclones. The roofs of homes are highly vulnerable to high winds, especially the overhanging leading edge, which is susceptible to uplifting. Bermuda and Florida are two areas with highly developed infrastructure that both often experience high tropical cyclone winds. Though both regions' residential building codes specify the same design wind loads of 150 mph or 300-year winds, there has been a noticeable discrepancy between the roof damage recorded in each location, with Bermuda roofs experiencing damage at a much lower rate than the common Florida asphalt roof. To quantify the differences in risk in each community, testing was done on a combination of roof geometry, construction material strength, and geographic future wind projections. Computational fluid dynamics simulations were conducted to determine how pressure accumulates on the two different roof geometries. The results showed that the Bermuda roofs experience 1.5 times less uplift along the leading edge when compared to the Florida asphalt roofs. Finite element modelling determined that the Florida model can withstand 9% - 40% more pressure before material failure, depending on the level of material weathering. However, when combined with the effects of geometry-driven pressure distribution, it was found that the Bermuda roof can withstand winds between 160.0 mph -167.8 mph, while the Florida asphalt roof can withstand speeds between 140.2 mph - 151.5 mph. After combining these failure wind results with projections of future wind speed return periods, it was determined that by the end of the century, Bermuda winds will be able to meet the 300-year wind design criterion, while the Florida roof will not. These results call for an update in the current ASCE wind load standards for Florida to protect hurricane-prone communities.