Revised power-law model to estimate the vertical variations of extreme wind speeds in China coastal regions

Typhoons originated from the Northwest Pacific pose severe threats on the coastal megacities of China. Hence, the typhoon-resistance capability should be given priority in the building designs along the coastline of China. The wind profile model, which has been widely used to estimate the vertical variation of wind loads, is of importance due to its value in evaluating the structural safety of the buildings under extreme wind conditions. In practice, the classical power-law model with four specific exponents has been recommended by the load code (GB 50009-2012) of China to calculate the vertical profile of extreme wind speeds. Based on the results of a series of artificial typhoon simulations, which have been verified by both the track data of historical typhoons and observations obtained from three land weather stations, the classical power-law model with the exponents recommended by the code is evaluated. It has been found from the evaluation that the classical power-law model is insufficient to estimate the vertical variation of design wind speeds in the coastal area of China. Consequently, an empirical correction ratio and a scale factor are introduced to provide more reliable estimates of extreme wind speeds with any desired return periods.