| The wind damage in the eastern region of China is significant effected by typhoons in the northwestern Pacific and the South China Sea,previous wind disaster statistics show that The loss in low-rise buildings caused by the typhoon wind damage is especially serious.The study on the mechanism of wind-induced damage of low rise buildings is beneficial to guide the engineering practice and relevant theoretical reference,wind-induced failure of low rise buildings is mainly determined by various wind parameter characteristics,therefore,considering the change of wind parameters alone is easy to evaluate the difference of wind-induced damage of low-rise buildings with different wind parameters.Wind parameters mainly include wind speed,wind direction,turbulence intensity,turbulence integral scale and power spectrum,Turbulence intensity is an important factor in wind tunnel test of structural wind load.Based on the homogeneous turbulence flow field of 3 different turbulence,the wind pressure characteristics and wind load characteristics of windward eaves,pediment region,ridge regions and corner region(vulnerable areas)of roofing of low-rise buildings with different slope angles are studied by wind tunnel tests,the influences of wind direction,slope angle and turbulence intensity on local wind pressure on roofing of gable-roofed low-rise buildings are discussed respectively.The results show that the wind pressure distribution characteristics of the roof,especially the corner region of windward roof edge,is significantly affected by the wind direction,the wind pressure of the local measurement point is relatively larger at 45°,so it’s easy to form a vulnerable area in the corner of the windward roof.Wind pressure shape coefficient of roof on gable-roofed low-rise building,especially the 0°~60°wind direction,is significantly affected by the slope angle,the wind pressure shape coefficient on roof is less affected by the slope angle when the airflow is parallel to the ridge,the increase of slope angle is helpful to reduce absolute value of shape coefficient on windward roof,and the wind-resistant performance of 30 ° slope house is better;The most unfavourable peak wind pressure mainly occurs in the corner,windward edge of eave and the ridge area close to the end of gable in oblique wind directions,moreover,the value and location of he most unfavourable peak wind are affected remarkably by roof pitches.The influence of turbulence on the mean wind pressure is not obvious,however,the fluctuating and peak wind pressure are affected greatly;The turbulence intensity is linear with fluctuating wind pressure coefficient of the roof,the proportion coefficients of local fluctuating wind pressure on theroof of different turbulent wind fields are given quantitatively;The influence of turbulence on the shape coefficient of windward and leeward roofs is not obvious,However,with the increase of turbulence,the absolute value shape coefficient tend to decrease on roof.Referenced to the Chinese standard ABC three types of landforms on the wind load shape coefficient value of roofing on low-rise buildings,the variation of shape coefficient of roof area on low-rise buildings is discussed by the influence of turbulence and landforms.The results show that consider the increase of turbulence intensity alone lead to absolute value of roof shape coefficient on gable-roofed low-rise buildings decrease,however,the increase of turbulence intensity leads to the increase of roof shape coefficient absolute value in ABC three types of landforms,this phenomenon also needs to consider the effects of wind velocity profile and other factors. |
