Quasi static study on tall building based on measured dynamic wind pressure

Abstract

One important issue that arrives the serviceability design of many high-rise buildings is wind-induced discomfort. The assessment of discomfort risk for the buildings occupants due to the wind action is, therefore, of primary importance. The treatment of wind loading, which is universally applied to the design of typical low to medium-rise structures, can be unacceptably conservative for the design of very tall buildings. This study presents the experimental results of evaluating wind pressure distributions on all four faces of a tall rectangular building with 1:1.5:7 ratio. The model is made up of the acrylic sheet with a geometric scale of 1:300 with plan dimension of 10 cm x 15 cm and height of 70 cm. The model is instrumented with 192 numbers of pressure taps at eight different levels were denoted as Level 1 to level 8 corresponding to the heights of z/H ratio (where H is the height of the model) are 0.10, 0.20, 0.30, 0.50, 0.70, 0.80, 0.90 and 0.95 respectively. The model is tested using a Boundary Layer Wind Tunnel (BLWT) for twelve angles (0°, 5°, 10°, 15°, 25°, 33.5°, 45°, 56.5°, 60°, 75°, 87.5° & 90°) of wind incidence under plain terrain condition. The measured pressure data have been integrated to evaluate mean pressure coefficients, drag & lift coefficients along wind direction and perpendicular to wind direction, mean moment coefficients at each of measured levels. The average pressure coefficient values on the windward face are almost comparable at all levels, while on the smooth face and side faces the lower levels have a minimum value compared to higher levels. Mean force coefficients for level 8 are always higher than all the other levels due to edge effect at top levels. The average drag coefficient values are a good agreement with code values (IS: 875 (Part3)-1987).