Koichi Miyashita

Wind-induced response of high-rise buildings Effects of corner cuts or openings in square buildings

Abstract Characteristics of both the wind forces acting on, and the responses of a square building with chamfered corners or openings are investigated. The wind forces acting on the building are obtained from the wind tunnel tests. The responses of the building are calculated through the employment of modal analysis, which uses the results of the wind tunnel tests. In this study, the importance of the correlation of the wind forces in X and Y-axis for the response analysis is addressed.

Full-scale measurements of wind-induced responses on the Hamamatsu ACT Tower

Abstract In Japan, most high-rise buildings are equipped with vibration control devices in order to improve their habitability by reducing wind-induced vibration. The Hamamatsu ACT Tower is also equipped with active type vibration control devices. For the purpose of confirming the vibration control effects of these devices, observations of winds and vibrations have been carried out. This paper reports on the vibration control effects of the devices on wind-induced vibration, as well as the results obtained from observations of vibration responses of the building during strong seasonal winds and a typhoon.

A case study of wind pressure and wind-induced vibration of a large span open-type roof

Abstract This paper reports on the results of wind tunnel tests and response analyses, both of which were conducted in order to obtain data for the wind resistant design of a large span roof. This roof is planned to be constructed in Kariya Japan. The study was composed of three parts. First, a wind tunnel test was carried out to investigate the characteristics of the wind force acting on the roof. Secondly, the response of the roof was estimated through the modeling of aerodynamic characteristics obtained from the wind tunnel test. Finally, a wind tunnel test, using an elastic model of the roof, was conducted and the test results were compared with the results of the response analysis. This paper only shows the results of the wind direction where the vibration response is found to be very large. In this case, small values of 0.1 ∼ 0.3 are shown for the mean wind pressure coefficient. however, the fluctuating wind pressure coefficients were found to be 0.2 ∼ 0.5 , fairly large values. The power spectral density for the fluctuating wind force shows almost the same shape regardless of the location on the roof surface. With respect to the fluctuating wind pressure, the pressure fluctuation on the upper surface is larger in the high frequency area. However, in the low frequency area, the pressure fluctuation on the lower surface is larger. The fluctuation of the wind force acting on the roof shows an intermediate value for both surfaces. Furthermore, when the results of the response analysis and the vibration test are compared, it is found that both results correspond quite well to each other, and that aerodynamic negative damping do not act on the roof.

Simultaneous wind measurements over two sites using Doppler sodars

Abstract In wind-resistant design of buildings and structures, it is very important to accurately assess the design wind speed at a particular site, considering the variation in wind speed with terrain roughness. In this study, the authors attempt to find a reasonable method for estimating design wind speed for a given terrain roughness, through simultaneous observations of atmospheric boundary layer wind speeds over two sites with different roughnesses using Doppler sodars. The mean wind speed profiles at the two sites during the same storms were compared to study the variation in mean wind speed as this is affected by inland terrain roughness.

Development of a measurement system using the Internet and its applications

The authors et al. have developed a measurement system which can analyze meteorological data transmitted to E-mail servers from several observation sites.This measurement system is effective for observations made at remote places due to the utilization of the Internet. It also has an advantage in that the data is sent over the Internet in real time. This paper gives an outline of this system and describes observation examples obtained through its use.