Study On Wind Pressure Characteristics On Curtain Wall Surfaces Of Tall Buildings

Wind load is the major consideration in the curtain wall design of tall buildings. The estimation of wind load extreme values is mostly based on the Gaussian assumption. However, researches and studies show that the flow separation, the shed wake vortex and reattachment generated by the bluff body make the wind pressure present strong non-Gaussian features. Following the Gaussian assumptions, the wind load on the curtain wall surfaces shall be underestimated, which shall affect the structure safety of tall buildings. Thus, a systematic study of the wind pressure characteristics on curtain wall surfaces of tall buildings and the adoption of an effective and reasonable method to accurately estimate wind load extreme values shall have theoretical and practical significances.Based on the rigid model wind tunnel experiments on Construction Building in Shangyu, this paper investigates the non-Gaussian features on curtain walls of the tall building under the influence of incoming flows, improves the Gumbel extreme value estimation method, and proposes a new extreme value estimation method by calculating long-term sample with short-term sample. The main contributions and results of this paper are summarized as the following.Firstly, brief introduction of the rigid model wind tunnel experiments on the diamond-shaped tall building with corner cuts and two most frequently adopted extreme value estimating methods: Classic Extreme Value Theory and Zero Up-crossing Theory.Secondly, a systematic study of the non-Gaussian features of wind pressures on curtain wall surfaces of the tall building; the statistics and distribution of wind pressure are analyzed. The non-Gaussian features of the fluctuating wind pressure are systematically studied through the following aspects such as the time domain, frequency domain, the probability distribution and the spatial correlation of wind pressure. For a better understanding of the wind pressure characteristics on the curtain wall surfaces, the division standards of the Gaussian and non-Gaussian regions are proposed based on the skewness-kurtosis testing method, the non-Gaussian regions of the fluctuating wind pressure in different directions on the building elevations are divided.Finally, the peak factor estimating method and extreme value distribution are discussed. The Gumbel extreme value estimation method is further improved; by calculating long-term extreme values through short-term samples, a new extreme value estimating method is proposed which is analyzed and compared with the current frequently-used estimating methods so as to verify its reliability.