Design of yielding metallic and friction dampers for optimal seismic performance

This paper deals with the optimal design of yielding metallic dampers and friction dampers together as they both have similar design characteristics and parameters. Ample tests and analytical studies have confirmed the effectiveness of these energy dissipation devices for seismic response control and protection of building structures. Since these devices are strongly non-linear with several parameters controlling their behaviour, their current design procedures are usually cumbersome and not optimal. In this paper, a methodology is presented to determine the optimal design parameters for the devices installed at different locations in a building for a desired performance objective. For a yielding metallic damper, the design parameters of interest are the device yield level, device stiffness, and brace stiffness. For a friction device, the parameters are the slip load level and brace stiffness. Since the devices and the structures installed with these devices behave in a highly non-linearly manner, and thus must be evaluated by a step-by-step time history approach, the genetic algorithm is used to obtain the globally optimal solution. This optimal search approach allows an unusual flexibility in the choice of performance objectives. For demonstration purposes, several sets of numerical examples of optimal damper designs with different performance objectives are presented. Copyright (C) 2003 John Wiley Sons, Ltd.