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Description:
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Overall loads acting on a full scale building in the natural vdnd environment are characterized in this work . The first objective of this research is to directly measure the overall wind loads on the test building at the Wind Engineering Research Field Laboratory (WERFL ) in the natural wind environment . The measurements are accomplished using four load cells , with one load cell placed at each comer of the building . These four load cells support the entire weight of the building , and each cell measures two shear forces and one vertical force acting at its comer of the building . These twelve forces were combined to measure total uplift , total horizontal shear , along , and across wind response .
Mean drag coefficients are calculated from these measurements in the natural wind environment and are compared to wind tunnel . Uncertainty in the measurements was expected , as several aspects of full -scale testing are difficult to control . Thermal reactions of the WERFL undercarriage were time varying and the variable weight distribution occurred upon lowering the undercarriage onto four point supports .
The second objective of this research is to develop a mathematical model using system identification to relate the three orthogonal fluctuating components of wind induced forces to the along , cross and vertical components of wind speed . An ARX (5 ,5 ) was found to be appropriate to capture the relationship between the free -stream wind turbulence and the turbulent wake characteristics . This model may then be used to generate modeled data or describe spectral relationships . Investigation in the frequency domain indicates that the building acts as a low -pass filter with the half -power frequency of 0 .08 Hz . |