CHARACTERISTICS OF WIND LOADS ACTING ON TALL BUILDINGS BASED ON THE MEASURED WIND FIELD IN URBAN CENTER

The wind profile is a main factor affecting wind load characteristics of tall buildings. To investigate characteristics of wind loads acting on tall buildings in urban central wind field, the measured wind speed data observed continuously from the Beijing Meteorological Tower during 2013-2017 was selected and the power-law was used to fit the measured wind profile based on the layered structure of the urban boundary layer. Wind loads of super-tall buildings with side ratios D/B=1, 2 and 4 in the measured wind field were obtained by carrying out a pressure test of rigid models in a wind tunnel and the results were compared with B and D wind fields in the code. The researches show that based on the layered structure, the power exponent of the measured wind field fitted by the power-law is 0.35. The mean wind velocity profile is similar to the D wind field, while the turbulence profile is larger than that of the D wind field. Compared with the wind load in B and D wind fields, the measured wind field has less effect on the mean wind load of super-tall buildings but a greater effect on the fluctuating wind load. Moreover, with the increase of the building side ratio, the fluctuating wind effect is enhanced significantly under the measured wind field. There is a strong correlation between the across-wind and torsional moment coefficients at the base, and correlation in the extreme values exists, especially for the building with D/B=4 at 90° wind direction, while two kinds of correlations are both enhanced in the measured wind field.