Mapping return values of extreme wind speeds

Structures subjected to wind loads must be designed to perform adequately from the points of view of stress and serviceability. Wind loading specified for design is based in part on the wind speeds affecting the site of interest. A particular quantity of interest in design is the N-year extreme wind speed, regardless of its direction, at a location of interest, defined by its longitude and latitude. Wind maps consisting of isotachs for N-year extreme wind speeds defined in building codes and standards are therefore required for structural design purposes. Alternatively, numerical versions of maps can be developed wherein automatic interpolations are performed that yield the N-year speeds at points defined by longitude and latitude. The raw data to be analyzed to develop the map are irregular time series of wind speeds above a specified threshold at multiple wind reporting stations. This work presents a two-stage approach to creating the map. The first stage involves the estimation of the parameters of an extreme value distribution at each station. In the second stage an interpolant based on the estimated parameters is created so that the N-year extremewind speedsmay be estimated at the geographical coordinates of interest. Standard errors and confidence bounds for the estimates are calculated using a non-parametric bootstrap algorithm. Results are presented for a region within Kansas, and those results are compared to the ASCE 7-10 Standard over the same region.