A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1979

This research is carried out in an attempt to derive the design wind velocities for Thailand through a statistical analysis of the available wind data. The design wind velocity for determining the critical stresses in structures is a probability statistic on a suitable function of wind velocity observations. Analysis of wind data suggests that annual extreme velocity observations of meteorological stations over a number of years provide the best available series. The observation stations all over Thailand have been grouped into five regions, i . e. North, North East, Central, East and South Thailand as classified by Meteorological Department. Power law is used to reduce the data for each station to gradient height, using the appropriate gradient height and power law exponent according to topography and surface roughness of the region. The famous Fisher-Tippet Type I distribution for extreme values is used for the probabilistic analysis of the data. From this analysis a linear equation is derived by the method of least squares to give the gradient velocity for any desired return period. Design wind velocities for each station are calculated for each station and velocity profiles are drawn for return periods of 100, 200, 300 and 400 years.