Facing the Storm

THE RULES CHANGE WHEN YOU'RE IN HURRICANE COUNTRY. ASCE 7-05 Minimum Design Loads fir Buildings and Other Structures requires that all buildings along the Atlantic and Gulf Coast be designed for wind loads produced by hurricane storms. This requirement applies as well to Hawaii, Puerto Rico, Guam, the Virgin Islands, and American Samoa. The wind speed map shown in ASCE 7's Figure 6-1 gives wind speed contours for the 3-second gust wind speed ranging from 90 mph all the way to 150 mph for a storm magnitude having a nominal return period (MRI) of 50 to 100 years. The commentary to the standard (Table C6-5) shows that these design wind speeds along most of the coastline correlate to an 'ultimate' hurricane wind level ranging from a Category 3 to a high Category 4 storm as defined by the Saffir-Simpson scale used by the National Hurricane Center. A designer can be assured that a steel building frame and the building envelope will perform well during these violent storms, provided all serviceability and strength limit states are addressed during the design phase, and proper construction techniques are followed.