Damping systems for new and retrofit construction

Damping systems, otherwise known as supplemental damping (energy dissipation) systems are being employed in the United States to provide enhanced protection for new and retrofit building and bridge construction. Such hardware includes displacement- and velocity-dependent dampers. The types of dampers being implemented mostly in the United States and Japan at this time are presented in the paper. Guidelines and commentary to aid in the implementation of passive supplemental dampers in existing construction are included in the new resource documents FEMA 273 and 274: Guidelines for the Seismic Rehabilitation of Buildings [ 1 ] and the FEMA 369: NEHRP Recommended Provisions for Seismic Regulations for New Buildings [2]. This paper introduces the FEMA 273 and NEHRP analysis procedures and outlines the modeling and analysis procedures developed for implementing damping systems. Two new developments in the field of damping systems that will facilitate their application to stift structural framing systems are the toggle-brace and scissor-jack damper configurations. These configurations are presented in the paper and !heir utility is demonstrated by comparison with conventional configurations for a sample single-story, single-bay frame. Examples of applications are presented.