Recommendation on Topographic Effect Correction Factor for Applying of Chinese National Wind Load Code

Abstract

Complex terrain changes the wind field characteristics significantly, especially on the mean wind speed and turbulence intensity during the separation zone of steep hills and escarpments. With the acceleration of urbanization process in China, a large number of super tall buildings, large-span and high-rise structures will be built in western and southern parts of China where the topography effects cannot be ignored in the wind-resistant design. Based on the Chinese Code GB 50009-2012, Japanese Code AIJ-2004, American Standard ASCE 7-10, Australian/New Zealand Standard AS/NZS 1170:2:2011, Euro code EN 1991-1-4:2005, ISO Code 4354:2005 and Canadian code NBC 2005, the topography influences of typical terrain are analyzed in details and the main parameters on topographic effect are given. On this basis, the improved topographic correction factor formulas for mean wind speed and peak wind speed are obtained. By comparing with the numerical examples, wind tunnel test and field measurement results in literatures, the applicability of the improved formulas are verified and provides a reference for future wind loading code amendments and wind-resistant design in complex terrain areas.