Measurement and identification of wind parameters at bridge site in complex inland terrain

In order to obtain the feature of wind field in complex inland terrain and provide correct basis for the calculation of wind load,after the different characteristics of strong inland wind and coastal typhoon had been studied,wind parameters of the two strong winds were compared from the causes,characteristics and other aspects. Through long-term wind observations of Longmen Yellow River Bridge,538 strong wind samples were obtained from multi-sites,multi-dimensional measuring points. Through the analysis of the measured wind speed samples,the distribution and regular pattern of measured wind parameters in inland strong wind areas are obtained. Under the influence of topography,wind speed and direction obey the basic rule of monsoon circulation and have obvious regional characteristics. The wind attack angle is- 9 ~ 8°,which is larger than that on plain area,and it should be determined on the measured data. Affected by complex terrain,the measured wind profile index does not comply with the power-exponential distribution,and the wind profile cannot bedirectly obtained by the specification. Turbulence and gust factor are different from the values in the Wind-resistant Design Specification for Highway Bridges(JTG /T D60-01-2004)(Hereinafter referred to as thespecification). The average values of turbulence intensity and gust factor are respectively between 0. 103 ~ 0. 13 and 1. 22 ~ 1. 39 and are different from the standard values. With the increase of the average wind speed,the two factors have a decreasing trend and there is a significant linear correlation between them. Turbulence integral scale is different from those recommended in the specification for plain area and is larger than normal value. Wind spectral fitting should follow the rule that different wind spectra and different formula should be chosen for different frequency region.