Earthquake resilient steel braced frames with controlled rocking and energy dissipating fuses

A new type of seismic resistant structural steel braced-frame system is introduced that employs controlled rocking, elastic post tensioning, and replaceable fuses to resist earth quake shaking with limited structural damage. Through the use of capacity design prin ciples, inelastic energy dissipation is confined to replaceable fuses while the controlled rocking and elastic post tensioning provide self-centering action to eliminate residual drift. Quasi-static cyclic tests and dynamic shake table tests of large-scale specimens confirm that the system can sustain extreme earthquake ground shaking with story drift ratios up to 3 % without structural damage. Owing to the well-defined rocking mechanism, analysis and design of the system is straightforward. Work is ongoing to develop design criteria and guidelines to facilitate practical implementation of these system in building design and construction.