Uncertainty Analysis Of The Extreme Wind Load On The Claddings And Components Of Low-rise Buildings

The wind load extremes on the claddings and components of low-rise buildings contain random uncertainties and cognitive uncertainties,which are derived from influencing factors such as incoming wind speed and direction,experimental measurement techniques,and extremes statistical methods.Based on domestic and foreign research on low-rise buildings,including the mechanism of the wind-induced damage,wind tunnel tests and theoretical methods,this paper takes the uncertainty of the wind load extremes of the claddings and components of low-rise buildings as the research object,mainly as follows:（1）To study the uncertainty in wind speed prediction with different recurrence intervals.Annual maximum wind speed samples of several regions for 30 consecutive years were extracted from the actual wind speed records of the meteorological database.The cognitive uncertainty of the extreme value probability distribution model and sample size were investigated separately.The results show that the higher the sample size the smaller the uncertainty contained in the extreme value estimates,and the most accurate wind speed prediction results in the recurrence period when the sample size is 30.The extreme wind speeds in typhoon areas contain higher uncertainties than in non-typhoon areas.When calculating the wind speeds at different recurrence intervals using the methods in the load codes,the extreme wind speed estimation coefficients for typhoon areas and non-typhoon areas should be specified separately.（2）To study the uncertainty contained in the extreme wind pressure coefficients.The wind pressure distribution characteristics and its uncertainty of the claddings and components of low-rise buildings were investigated based on the Cook-Mayne method and Hermite moment model theory using the data information from the wind tunnel test of the low-rise building at the University of Western Ontario.The results show that the windward wall surface is mainly subject to wind pressure,and the larger the skew factor is,the smaller the wind suction force and the larger the wind pressure is;the wind suction force on the side wall surface is larger than that on the roof surface than that on the leeward wall surface,and the relationship between the kurtosis coefficient and the skew factor and the wind suction force are negatively and positively correlated,respectively.The influence of different building forms on the extreme wind pressure coefficient is also clarified.The higher the roof height,the higher the uncertainty of the extreme values of wind pressure coefficient at the eaves and ridge,the slower the roof slope,the higher the uncertainty of the extreme values of wind pressure coefficient at the eaves,and the steeper the roof slope,the higher the uncertainty of the extreme values of wind pressure coefficient at the ridge.（3）The uncertainties of extreme wind speed and extreme wind pressure coefficient were considered comprehensively,and the first-order and full-order methods were used to study the extreme wind load of the claddings and components of low-rise buildings,including the effects of the coefficient of variation of wind speed extreme and the coefficient of variation of extreme wind pressure coefficient on the extreme wind load values for different recurrence intervals.The results show that the variation coefficient of wind speed extreme has more influence on the wind load extreme,and the larger the recurrence interval is,the more obvious the influence of the variation coefficient is;the smaller the recurrence period is,the worser the influence of the variation coefficient of wind speed in the recurrence period on the wind load extremes.