Design and Retrofit Methodology for Building Structures with Supplemental Energy Dissipating Systems

Keywords: Nonlinear viscous dampers. Multistory buildings. Steel buildings. Flexible buildings. Supplemental damping devices. Earthquake resistant design. Retrofitting. Design algorithms. Structural velocity. Equivalent viscous damping. Normalized damper capacity. Capacity demand spectral design approach. Pushover analysis.

Abstract: This report focuses on two fundamental issues related to the design of nonlinear viscous dampers for building structures: structural velocities and equivalent viscous damping. It begins with an overview of the capacity-demand spectral design approach and includes various steps involved in the pushover analysis to determine the structural capacity. An alternative elasto-plastic analysis approach is also introduced. Fundamental considerations for the design of supplemental damping systems are reviewed and the design formulations for a pseudo-actual velocity transformation are given following a discussion of the differences between the two quantities. The proposed equivalent linear damping for the nonlinear [viscous nature] devices based on the equivalent power consumption approach is presented. Finally, various phases involved in designing supplemental systems are given Design steps for 2 alternative device configurations are given. A retrofit design example of a 9-story flexible steel building is presented and the performance of the two alternative configurations is discussed. (Abstract adapted from text).