Discussion of "Wind Speeds in ASCE 7 Standard Peak-Gust Map: Assessment" by Emil Simiu, Roseanne Wilcox, Fahim Sadek, and James J. Filliben

The ASCE 7 peak-gust map divides the U.S. into 2 main adjacent wind speed zones that do not reflect correctly the country's differentiated extreme wind climate. This discussion article comments on a paper (Simiu et al, April 2003) that shows that the methodology used in the map's development averages out real climatological differences and causes severe bias errors for the following reasons: 1) estimation of the speeds was based on superstations, of which 80% included stations that were also contained in 1 or more other superstations; 2) stations with significantly different physical geography and meteorology were in many cases included in the same superstation; 3) legitimate wind speed data was omitted from data records in cases in which analyses resulted in speeds different from those postulated in the map; and 4) off-the-shelf smoothing software was used that does not account for physical geography and meteorological differences. Case studies reported in the original article showed that the map entails severe bias errors, causing unnecessary waste due to overestimated wind loads or potential losses due to underestimated wind loads. In this commentary, Peterka and Esterday contend that Simiu et al fail to demonstrate an improved analysis methodology and have not understood the improvement of the gust map in reducing sampling error over the earlier fastest-mile map. The commentary authors address each of the four points above and conclude that while the current ASCE 7 wind map is based on reasonable analysis, additional analysis incorporating recent wind data would be beneficial.

  • Availability:
  • Authors:
    • Peterka, Jon A
    • Esterday, William S
  • Publication Date: 2005-6


  • English

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  • Accession Number: 01001841
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 14 2005 10:11AM