DESIGN CRITERIA AND LOADS
R. J. McNamara, S.E.
Adding damping with various energy dissipating devices has become an accepted method to reduce wind-induced vibrations in tall buildings. An example of a 39-story office tower is presented where large projected accelerations generated by the vortex shedding of an adjacent existing 52-story building are reduced by a passive system composed of viscous dampers and a motion amplification system. A description of the damping system and its analytical complexities are discussed. Non-linear analysis of the tower, using time history forcing functions derived from the wind tunnel is presented. Cost data for the damper system is also presented.
The use of energy dissipating devices to reduce building response from dynamic inputs has become an accepted design approach for high-rise buildings. New approaches are continually being developed by designers as evidenced by the varied applications of tuned mass dampers, sloshing dampers, visco-elastic dampers, friction dampers and viscous dampers. Each of these systems has its own idiosyncrasy and which is most appropriate must be evaluated for the particular project under consideration.
This paper presents the results of an investigation of the application of viscous dampers in a high-rise structure located in an urban environment. The structure, a 39-story steel-tube frame was designed using conventional wind engineering methods with code loadings and standard deflection limitations. A model of the tower was tested in a wind tunnel of RWDI facilities in Canada. The building is located within the immediate proximity of a 52-story tower in the center of a coastal downtown urban environment. Wind tunnel results