| Summary: | 碩士 === 淡江大學 === 土木工程學系碩士班 === 103 === In today''s developed society, the explosion in population accelerates the growth of high-rise buildings in urban terrains. However, limited by land resource, high-rise buildings tend to be constructed by means of lighter material and higher levels, which inevitably results in a sensitive feature to wind-excited response rather than earthquake. Therefore, to understand the dynamic behavior of a tall building under wind loadings is attracting more and more concerns. Interference effect between any two neighboring buildings is especially focused in an urban area. The complex phenomenon may be triggered by many factors, such as surrounding flow characteristics, geometric appearance of buildings, relative positions of neighboring buildings, wind attack angles, etc. Many publications regarding this phenomenon have been carried out in domestic or overseas journals and reports. Generally speaking from the literature, such complicated phenomenon cannot be simply linearly superposed one by one.
The present study was conducted to idealize the sources of interference effect and easy to investigate. By means of wind pressure measurement, a square prism model with aspect ratio 6 in a suburban turbulent boundary layer flow (α=0.24) was utilized as a principal building. Meanwhile another identical square prism model made by Balsa wood was utilized as interfering building and installed in several interfering positions. Instantaneous pressures over the principal building''s surface were recorded by at least 90 runs. Each run represents a 10-minute record in full scale. By normalized to velocity pressure at roof top, pressure coefficients were calculated and the maximum and minimum values were found. Based on extreme value theory, the Gumbel and Weibull distribution types were identified for different pressure tap positions due to different flow conditions. Then the design for cladding was briefly introduced.
Experiment results showed that the maximum wind pressure coefficient was occurred in (x/B,y/B) = (3,3) position, representing that significant interference effects in the oblique configuration. The minimum pressure coefficient was found when the interfering building is in the upstream (y/B = 0). However, in this research, only the range between x/B = -3 ~ 3 and y/B = 0 ~ 3 were examined, the discussion on extreme values may be limited and the greater effect could occur outside the experiment range.
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