Ultimate Wind Load Design Gust Wind Speeds in the United States for Use in ASCE-7

This paper presents an overview of the approach employed in the development of the wind speed maps for use in ASCE 7-10. The reason for a reduction in the wind speeds in the new standard as compared to those given in the ASCE 7-98 through 7-05 standards is presented, as well as the reason for the reintroduction of Exposure D along the hurricane coastline. The most significant change in the wind speed maps from the previous version is the shift from a single map for an importance factor for buildings and other structures of 1.0 to three separate maps, one for each category of occupancy, thus eliminating the need for importance factors that vary between hurricane and nonhurricane regions.