Abstract
A new seismic control device using a ball screw mechanism as an apparent mass amplifier has been developed, which is referred to as the tuned viscous mass damper (TVMD). This device enables effective seismic control using a tuned mass. For a multiple-degree-of-freedom (MDOF) seismic control system incorporated with the TVMD, a design method based on numerical optimization has been previously presented by the authors. However, simpler design methods that are suitable for a practical design have not yet been presented. At the preliminary design stage, it is essential for structural designers to understand the seismic response characteristics of the structure in terms of modal responses. However, a complex-valued eigenvalue analysis, which most structural designers are unfamiliar with, is required for accurate seismic response estimation. This is because the seismic control system incorporated with TVMDs is nonproportionally damped. In this paper, the authors propose a seismic response estimation method that does not require a complex valued analysis. An analysis example illustrates that the square root of the sum of the square (SRSS) of the maximum modal responses derived from the undamped real eigenvalue analysis gives a good approximation in practical terms.
