The usage of special materials with unique properties in seismic resistant structures has increased since the 1994 Northridge earthquake to overcome limited energy dissipation and ductility. Among them, shape memory alloy (SMA) is a unique metallic alloy that has the ability to undergo large deformations and revert back to its original un-deformed shape. Thus, a simple and practical hybrid damping device equipped with SMA that provides both energy-dissipating and re-centering (strain-recovering) capabilities is developed and evaluated in the present paper. Quasi-static loading tests on Nitinol bars are conducted to obtain their mechanical properties in tension and compression. The optimum proportion of SMA and steel in the device is achieved through analyzing various models. Placing the proposed device in semi-rigid bracing members of special structures will localize the energy-dissipating and ductility while providing the brace with strainrecovering capability.

Incremental dynamic analysis (IDA) is an emerging method in structural analysis which allows evaluation of seismic capacity and demand of structures through a series of nonlinear dynamic analyses using multiple scaled ground motion records. Seismic behaviour of concentrically braced frames designed based on the first, second and third revisions of the Iranian seismic code, standard no. 2800, has been evaluated through IDA in the present paper. Besides, a brief comparison is made between seismic behaviour of these frames, frames with different heights and different bracing types. Seismic capacity and limit states of such structures have been reviewed through the paper. The IDA results imply that frames designed with the first edition are seriously vulnerable and fail before reaching the acceleration levels predicted in the code. On the other hand, frames designed with the second and third editions, although behaving better, need partial reinforcement in some cases. Other results of this study show that chevron braced frames behave seismically better than X‐braced ones. Copyright © 2009 John Wiley & Sons, Ltd.

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