Cyclic engagement of hysteretic steel dampers in braced buildings: a parametric investigation

Abstract

Hysteretic steel dampers have been effectively used to improve the seismic performance of framed buildings by confining the dissipation of seismic energy into sacrifical, replaceable devices which are not part of the gravity framing system. The number of cycles sustained by the dampers during the earthquake is a primary design parameter, since it can be associated to low-cycle fatigue, with ensuing degradation of the mechanical properties and potential failure of the system. Current standards, like e.g. the European code EN 15129, indeed prescribe, for the initial qualification and the production control of hysteretic steel dampers, cyclic tests in which the devices are assessed over ten cycles with amplitude equal to the seismic design displacement dbd. This paper presents a parametric study focused on the number of effective cycles of the damper during a design earthquake in order to assess the reliability of the testing procedure proposed by the standards. The study considers typical applications of hysteretic steel dampers in low and medium-rise steel and reinforced concrete framed buildings and different ductility requirements. The results point out that the cyclic engagement of the damper is primarily affected by the fundamental period of the braced building and the design spectrum, and that, depending on these parameters, the actual number of cycles can be substantially smaller or larger that recommended by the standards. A more refined criterion for establishing the number of cycles to be implemented in testing protocols is eventually formulated.

Stiffening effects-controlling sizing procedure of ADAS dampers in seismic retrofit of frame structures

“…Then, E d,p,t is obtained by summing to E d,p,c the energy dissipated in all remaining cycles with smaller amplitudes, E d,p,r . E d,p,r was evaluated to be about 10 times greater than E d,p,c in a recent extensive numerical research (Gandelli et al, 2021). At the same time, a similar value was preliminarily estimated in this study for simpler frame structures than the case study one, not reported here for brevity's sake, by extending the findings of a previous study of the authors carried out for a special infrastructure (Sorace et al, 2016).…”

“…Among the strategies based on the incorporation of supplementary damping devices, those making use of Added Damping and Stiffness (ADAS) steel dissipators have a well-established tradition (Bergman and Goel, 1987;Whittaker et al, 1991;Aiken et al, 1993;Martinez-Romero, 1993;Tsai et al, 1993;Dargush and Soong, 1995), updated to recent developments too (Mazza, 2014;Teruna, 2015;Moghaddasi and Namazi, 2016;Sorace et al, 2016;Mohammadi et al, 2017;Mazza and Imbrogno, 2019;Shojaeifar et al, 2020;Gandelli et al, 2021;Khoshkalam et al, 2022). This is a consequence of the plain working principle of these devices, based on the elastic-plastic behaviour of the constituting plates, as well as of their relatively easy installation.…”

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

“…The diagonal steel braces equipped with the hysteretic dampers are modelled by means of a truss element object [48] with an assigned uniaxialMaterial elastic-perfectly plastic behavior, as commonly implemented in other studies (e.g., [43,44,[57][58][59]).…”

Development and optimization of a novel response‐amplified friction damper with different friction pairs

“…Friction dampers feature simple construction and significant energy dissipation without problems of material yield, leakage, and fatigue 2,3 . Under seismic loading, repeated forces may lead to concentrated wear at the friction interfaces 4 . The rapid functional restoration of the damper can be achieved by replacing the locally damaged friction components 5 …”

“…2,3 Under seismic loading, repeated forces may lead to concentrated wear at the friction interfaces. 4 The rapid functional restoration of the damper can be achieved by replacing the locally damaged friction components. 5 Friction dampers can be categorized into translation-type, rotation-type, and shear-type devices based on frictional trajectory.…”