Basis for recommending an update of wind velocity pressures in Canadian design codes

Reference wind velocity pressures corresponding to specified return period wind speeds are provided in several Canadian design codes. A review of the two most recent editions of the National Building Code of Canada (NBCC) indicates that significant changes in some 50-year return period wind speeds, vAH-50, were introduced in the 2010 version of the NBCC-2010 compared to the previous NBCC-2005. The changes are due to analysis approaches, available wind records, and a re-examination of anemometer histories. To potentially improve the estimates of vAH-50, wind records in the Environment Canada HLY01 digital archive were processed. Two hundred and thirty-five meteorological stations are considered in the analysis, and height and exposure corrected annual maximum hourly-mean wind speed, VAH, are extracted. Statistical analysis and distribution fitting were carried out using the Gumbel distribution and generalized extreme value distribution and several fitting methods were employed. The results indicate that it...