Applying Large Weight Mass Dampers to Improve Seismic Resistance of Buildings and Structures

Mass dampers (MD) are theoretically very effective for decreasing dynamic loads on structures, but two fundamental difficulties arise in their implementation. First, the MD is sensitive to tuning, and small deviations in the stiffness or mass of the MD stop its working. Second, the damper displacement exceeds the structure displacement by as many times as the mass of the structure exceeds the MD mass. To eliminate these difficulties, it is necessary to significantly increase the MD mass. For the MD of large mass, there is a critical mass value, above which the damping effect disappears. In the studies of the authors, the connection between the critical mass and damping in the protected structure is shown. The greater is damping in a structure, the smaller is critical mass of the MD. Another feature of a large mass MD is the significant influence of the type of damping in the structure and in the MD spring on the tuning parameters. The applied methods of damping setting lead to significantly different optimal characteristics of the MD. In addition to these features, there may be a question of combining loads in the selection of the MD. In addition to the classical MD, the two-mass MD with consecutive or parallel additions of mass are considered. This solution makes it possible to expand the area of effective operation of the MD and reduce the force in the main damper spring.