A New Stainless-Steel Tube-in-Tube Damper for Seismic Protection of Structures

This paper investigates a new stainless-steel tube-in-tube damper (SS-TTD) designed for the passive control of structures subjected to seismic loadings. It consists of two tubes assembled in a telescopic configuration. A series of slits are cut on the walls of the exterior tube in order to create a series of strips with a large height-to-width ratio. The exterior tube is connected to the interior tube so that when the brace-type damper is subjected to forced axial displacements, the strips dissipate energy in the form of flexural plastic deformations. The performance of the SS-TTD is assessed experimentally through quasi-static and dynamic shaking table tests. Its ultimate energy dissipation capacity is quantitatively evaluated, and a procedure is proposed to predict the failure. The cumulative ductility of the SS-TTD is about 4-fold larger than that reported for other dampers based on slit-type plates in previous studies. Its ultimate energy dissipation capacity is 3- and 16-fold higher than that of slit-type plates made of mild steel and high-strength steel, respectively. Finally, two hysteretic models are investigated and compared to characterise the hysteretic behaviour of the SS-TTD under arbitrarily applied cyclic loads.