DEVELOPMENT OF APPLICABLE STATISTICAL MODEL FOR BASIC WIND SPEED DISTRIBUTION IN NIGERIA

Abstract

Wind loading estimation is one facet of the entire design process. The estimation of wind load is of prime importance in the design of tall buildings and other structures subjected to wind pressure.As a climatic process which is time-dependent, wind speedrequires proper assessment in order to predict its speed for specified return periods. This requires a good understanding of the wind process within the lower atmosphere which is of interest to the designer of civil engineering structures. The research aims atdetermining the distribution of basic wind speed across Nigeria using improved data and applicable statistical model via collected yearly wind speed data from 37 meteorological stations for fifty years (1965-2015).After the collection of data, it was ranked from the smallest to the highest (ascending order).The probability of non-exceedence was then calculated using Gumbel Type 1 distribution method; the return period was calculated for thirty-seven stations. The annual wind speed data were plotted against the reduced variate. The predicted wind speed data were used to generate an isopleth map with the aid of a software named Surfer 15. The maximum wind speed data obtained from the thirty seven (37) meteorological stations across Nigeria for fifty years ranges between 43.4m/s to 58.7m/s.The predicted gust speed data obtained from the analysis using Gumbel’s method is classified into four zones depending on the magnitude of the wind gust. It was observed that eighteen (18) meteorological stations belong to Zone 1, six (6) meteorological stations belong to Zone 2,nine (9) stations belong to Zone 3 and four (4) stations belong to Zone 4.Zone 1 includes areas where wind speed ranges from43.4 m/s to 51 m/s, Zone 2 ranges from 51.1 m/s to 55 m/s, Zone 3 ranges from 55.1 m/s to 56 m/s and Zone 4 ranges from 56.1 m/s to 59 m/s.