A Comparative Study About Field Measurement And Wind Tunnel Testing Of Typhoons-induced Wind Loads On Gable Roof Low-rise Buildings

According to statistics about eight typhoons landfall in china each year,which is located in the Western Pacific coastal region,accompanied by wind-related disasters caused huge losses to our national economy.Therefore,it has great reference value to study the characteristics and mechanism of Typhoon for building structures design in terms of wind resistance.hn this thesis,the wind loads on low-rise building during typhoons were studied through field measurements and wind tunnel tests.The major objective of the study is to further understand near ground lyphoon-n-generated wind characteristics and wind loads on low-rise buildings under extreme wind conditions during typhoon landfalls.The major objective and achievements of this study are as follows:(1)Based on strong wind speed data at five different height recorded from meteorological tower at sites near seashore for coastal terrain,discussed the near ground typhoon-n-generated wind characteristics of the landfall typhoons "Mujigae","Ketsanaa and "Parma".The result revealed that in the near-surface range vertical distribution of mean wind speed can be well described by a logarithmic law and a power law.The wind profile exponent and the length of surface roughness are approximately same as that stipulated in Chinese wind loads Standard GB50009-2012 for coastal terrain exposure.The turbulence intensity profile satisfy a power law.The mean value of longitudinal turbulence intensity at five heights also accord with Chinese wind loads Standard,but less than the American wind loads Standard ASCE-7-10 and the Japanese wind loads Standard AIJ.The profile of gust factor satisfy a power law as well and the measured value are larger than Chinese wind loads Standard.(2)By introducing a dimensionless wind parameters U10/u*to study the relationship between the parameters of wind field and establish an empirical formula between wind profile index,turbulence intensity and wind parameters.Based on the existing theory and combined with the empirieal fornula,creating a series of theoretieal formulas to estimate the value of wind profile exponent,turbulence intensity and gust factor.(3)Wind tunnel tests were conducted to assess the wind loads on the 1:4 gable roof low-rise experimental buildings.The influence of surface roughness on wind pressure coefficient was discussed by simulating different wind conditions.The model test results were compared to the field measurements to evaluate the accuracy of the wind tunnel simulations.Further comparisons of the full-scale measurements and wind tunnel simulations of wind pressure coefficient near the roof ridge comers,roof eave comers and roof central axis showed distinct discrepancies.The results revealed that wind tunnel test results underestimated the field measured negative peak and fluctuating pressure coefficients at roof ridge comers and roof eave comers.The mean wind pressure coefficient of wind tunnel test results was close to the field measured value at roof central axis region.(4)By using Bootstrap method and improved Gumbel method can effectively reduce the influence of randomness on extreme wind pressure.Compared with experimental observations,the estimation interval by Bootstrap method was slightly lower,however the results of Gumbel method fluctuate near the observed results.