Design of energy dissipation devices based on concept of damage control

Recent laboratory and theoretical studies show that structures with added energy dissipation devices will generally exhibit inelastic behavior when they are subjected to strong ground motion; therefore, the assumption of linear structural responses has to be eliminated in the design of such devices for the purposes of structural upgrade and retrofit. In this paper, effects of high damping on a structure experiencing inelastic deformation under seismic ground motions are examined. The importance of the energy concept in the design of energy dissipation devices for structural applications is addressed, and a new design method is proposed based on the concept of damage control. To establish a rational design approach, an explicit procedure is developed to transform a multidegree-of-freedom system to an equivalent single-degree-of-freedom model in the inelastic range so that the evaluation of structural seismic performance with and without the added devices can be easily performed. While the example is given for the application of viscoelastic dampers, the proposed method is also applicable to other devices, such as friction and viscous dampers, under certain conditions.