Research and experience from past earthquakes suggest the need for buildings that are less vulnerable to damage and easier to repair after a major earthquake. Of particular concern are certain conventional systems, such as concentrically braced steel frame buildings, which are quite prevalent and whose design may rely on more inelastic energy dissipation than the systems can provide. This research aims to develop a new structural system that employs controlled self-centering rocking action and replaceable structural fuses to provide safe and cost effective resistance to earthquakes. The system combines desirable aspects of conventional steel-braced framing with innovative self-centering rocking action that employs high strength post-tensioning and replaceable shear fuses. After preliminary investigations of several possible fuse types, the research focused on steel fuses consisting of thin mild-steel plates with butterfly-shaped flexural links. Guided by performance-based capacity design principles, the fuses are easily replaceable and can be tuned to provide optimal performance. Through a combined program of computational and experimental research, the project encompasses component and complete system response and synthesis of the results through a methodology for performance-based design that directly assesses life safety and life-cycle economic factors. The proposed concept emphasizes damage prevention to foundations and other structural elements that are difficult to repair; inelastic energy dissipation in structural fuses that are easy to replace; story drift control so that nonstructural damage is reduced; and sufficient safety against collapse. The research program includes (1) development and testing of the steel butterfly fuses at Stanford University, (2) quasi-static testing of a large-scale frame subassembly at the NEES facility at the University of Illinois, and (3) dynamic shake table testing of a large-scale rocking frame at the E-Defense facility table in Japan.