Summary: | Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011. === Cataloged from PDF version of thesis. === Includes bibliographical references (p. 64-65). === Building higher skyscrapers increases the concern of wind induced motion. Indeed, in order to ensure serviceability and safety standards, it is the engineers' responsibility to investigate the response of high-rise buildings to wind excitation. Tuned mass dampers are usually used to limit the response of the buildings to wind. However, these devices are generally tuned for a particular bandwidth of frequencies. Therefore, in order to improve the effectiveness of these devices, control schemes must be implemented. For this thesis, the design of a modified friction device (MFD) has been studied. Requiring only a small amount of energy, the MFD is a new kind of semi-active damper that provides stability, accurate control and effectiveness. Using a MATLAB program, it was possible to model a primary structure hit by a certain wind excitation. The modified friction device was designed to counterbalance the effects of wind and decrease displacements and accelerations. It was placed on the top of the building where the displacements are generally the highest. The parameters of the MFD were examined, and many simulations were run in order to optimize the action of the device on the mitigation of wind excitation. The results demonstrate that the MFD effectively mitigates wind induced motion in buildings. Therefore, this thesis corroborates the benefits of implementing modified friction devices in civil structures. === by Saad Mikou. === M.Eng.
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