Chiba port tower: Full-scale measurement of wind actions Part 2. Basic properties of fluctuating wind pressures

Abstract

This paper contains the study concerning the basic properties of pressure fluctuations which has been investigated on Chiba Port Tower starting about one year ago for the purpose of making clear the characteristics of wind pressure on claddings of building. The record of strong wind which we have selected as our observation object this time is taken only at the time of Typhoon whose wind speed at the top of the building is 20 m/s and over. Resultantly, the value of r.m.s. pressure coefficient depends largely on turbulence intensity of wind speed and the r.m.s. pressure coefficient is almost twice of turbulence intensity of wind speed on windward face, and about twice or three times on side face. According to power spectrum analysis, Kárman vortex is recognized to occur periodically from this building, and Strouhal number is about 0.08∼0.11 based on the one side length of the building. Also the peak factor of pressure fluctuations on side and leeward faces, compared with the values on windward face, both mode and dispersion are large. It is cleared that the peak factor of pressure fluctuations on side and leeward faces inclines to be considerably larger than the peak factor of wind speed when the averaged period of peak value is under 0.5 second.