A study on using wide‐flange section web under out‐of‐plane flexure for passive energy dissipation

Abstract

It is not common to purposely subject the web of wide-flange or I-sections to out-of-plane bending. However, yielding the web under this loading condition can be a stable source of energy dissipation as the transition at the corner from the web to the flanges is smooth and weld-free; this prevents stress concentrations causing premature failure and eliminates uncertainties and imperfections associated with welding. Further, short segments of wide-flange or I-sections constitute a simple and inexpensive energy dissipating device as minimum manufacturing is required and leftovers not useful for other structural purposes can be re-utilized. This paper proposes a new type of seismic damper in the form of braces based on yielding the web of short length segments of wide-flange or I-shaped steel sections under out-of-plane bending. The hysteretic behavior and ultimate energy dissipation capacity is investigated via component tests under cyclic loads. The experimental results indicate that the damping device has stable restoring force characteristics and a high energy dissipation capacity. Based on these results, a simple hysteretic model for predicting the load-displacement curve of the seismic damper is proposed, along with a procedure for predicting its ultimate energy dissipation capacity and anticipating its failure under arbitrarily applied cyclic loads. The procedure considers the influence of the loading path on the ultimate energy dissipation capacity. Finally, shaking table tests on half-scale structures are conducted to further verify the feasibility and effectiveness of the new damper, and to assess the accuracy of the hysteretic model and the procedure for predicting its failure.

Entropy Analysis for Damage Quantification of Hysteretic Dampers Used as Seismic Protection of Buildings

“…Sci. 2017, 7, 628 9 of 14 time shaking table tests [46]. To calculate ID, first the curve that relates the axial force N endured by the damper with the axial relative displacement of its ends ∆ measured during the tests is split into the so-called "skeleton part" and "Bauschinger part".…”

“…Next, the index ID is obtained from the energy dissipated by the damper in each part and in each loading domain. A more detailed explanation of this decomposition and the precise equations to obtain ID can be found in reference [46]. Note that although the ID index will be the same for all the I-sections of one particular damper (it evaluates damage of the whole damper), the RWEE index will be different, because vibration tests are carried out for each I-section and its particular level of damage.…”

“…They were calculated following [46]. The index ID measures the level of damage between 0 (no damage) and 1 (imminent failure) and its accuracy has been verified experimentally through dynamic real-time shaking table tests [46]. To calculate ID, first the curve that relates the axial force N endured by the damper with the axial relative displacement of its ends ∆ measured during the tests is split into the so-called "skeleton part" and "Bauschinger part".…”

“…The values of the mechanical damage index ID i at the end of each seismic simulation are shown in Table 1. They were calculated following [46]. The index ID measures the level of damage between 0 (no damage) and 1 (imminent failure) and its accuracy has been verified experimentally through dynamic real-time shaking table tests [46].…”

Experimental Study and Application of Metallic Yielding–friction Damper

“…They can broadly be classified into two categories: (1) the shear type metallic yielding damper with a number of openings is subjected to in-plane shear deformations where the energy is dissipated through the shear plastic yielding of metallic yielding plates, such as the honeycomb damper, slit damper and single round hole damper [Karadelis and Omair, 2001;Tnanka et al, 2003;Oh et al, 2009;Zhang et al, 2012]; (2) the bending type metallic damper utilizes flexural deformation of metallic plates under the out-of-plane bending, such as the ADAS, triangular metallic damper [Whittaker et al, 1991;Tsai et al, 1993;Llera, 2004;Chan and Albermani, 2008;Benavent-Climent, 2010;Benavent-Climent, 2011].…”