Design Wind Load And Reduction Coefficient On Claddings Of Large-Span Spherical Roof

At present, many wind-induced disasters of large-span roof show that the current wind load specification can no longer meet the requirements of rise-span roof structure, therefore it need to be more in-depth study. Based on wind tunnel test data of large spherical roof, roof surface wind load distribution characteristics are analyzed,then use extreme value theory to analyze the roof of extreme pressure and give reasonable design wind loads. The main contents are as follow:1、Introducing various methods currently in use to estimate the extreme wind pressure on the claddings of large-span roof, including zero crossing theory estimation method and extrem value theory estimation method. Which focuses on extreme wind pressure estimation method based on extrem value theory.2、Analysis the distribution characteristics of mean wind, fluctuating wind, the measured minimum wind pressure of spherical roof surface of different rise-span ratio.And analysis the effects of the different rise-span ratio, different supporting height and different wind speeds.The results show that rise-span ratio’s influence for the mean wind, fluctuating wind and measured minimum wind pressure is relatively large, the supporting height influence over the rise-span ratio is small, wind speed has no influence.3、Based on the single extreme value theory, use theories of General Extreme Value (GEV) model and General Pareto Distribution (GPD) model respectively calculate the extreme wind pressure and analysis the two methods. The results showed that the GEV is more accurate than the GPD and get the envelope of78%reliability for minimum wind pressure coefficients of different rise-span based on GEV.4、Use multivariate extreme value theory analysis the correlation of extreme wind pressure from the qualitative and quantitative point, and use the structural variables method to obtain a joint reliability of78%of the wind pressure extreme.Then discussed the relationship between the correlation coefficient and pressure reduction coefficient of the wind extreme pressure. Then divided pressure zone and give the reduction result of extreme wind pressure coefficients for each pressure zone of different rise-span ratio spherical roof.