Analysis Of Wind Field Characteristics Of Zhoushan Island Connecting Project

With the development of science and technology,bridge spans have become larger and larger,structures have become more flexible,and damping has become smaller and smaller,which makes long-span bridges more and more affected by wind.Wind is one of the controlled loads of long-span bridges.The characteristics of natural wind fields have an important influence on the wind effect of bridges.Therefore,studying the characteristics of natural wind fields at bridge sites is of great significance for bridge wind resistance design.Based on the wind and wind effect system monitoring installed on the Xihoumen Bridge and Jintang Bridge in the Zhoushan Island Project,this paper obtained long-term wind field monitoring data(2013-2017),focusing on the analysis of the daily wind field characteristics and the wind field characteristics of three typhoons called Fette,Fenghuang and Canhong.The analyzed wind field characteristics mainly include mean wind speed,mean wind attack angle and mean wind direction angle,turbulent Reynolds stress,turbulence intensity,fluctuating wind power spectrum and turbulence integral intensity,etc.,Comparatively analysing the main wind field characteristics of daily wind and typhoon.research shows:(1)Based on the prototype monitoring wind field data,the characteristics of the daily wind field at the bridge site of Zhoushan Island Connecting Project were studied.Studies have shown that the characteristics of the wind field change periodically from year to year,and the statistical characteristics of wind speed in different quarters are basically the same,but the statistical characteristics of wind direction change significantly with quarters.In addition,the turbulence intensity in the first quarter was higher than that in the other quarters,and the turbulence integral scale variation pattern was basically the same throughout the year.(2)Based on the prototype monitoring wind field data,the wind field characteristics under the influence of typhoons on the Xihoumen Bridge and Jintang Bridge are studied.Studies have shown that for offshore typhoons,the wind field characteristics are less affected by local topography,and the wind field characteristics of the two bridge sites are basically similar.But for landing typhoons,the typhoon is significantly affected by the terrain.(3)Based on the prototype monitoring wind field data,the difference between the bridge daily wind field and the typhoon wind field is revealed,that is,the average wind speed of the typhoon is 2 to 3 times that of the daily wind,the wind attack angle is smaller than the daily wind,and the downwind turbulence integral scale is larger than the daily wind.In terms of turbulence scale,the difference between daily wind and typhoon is not so obvious.