Numerical Investigation of the Failure Mechanism of Short and Very Short Shear Links Made from ASTM A992 Steel

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Document Type : Article

Authors

1 Department of Civil Engineering, Azerbaijan Shahid Madani University, Tabriz, Iran

2 M.Sc. in Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran.

3 M.Sc. Student of Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran.

Abstract

There are numerous uncertainties in determining the rotation capacity and overstrength factor of shear links, which have raised concerns among structural designers regarding the design provisions in the AISC 341 code for accurately characterizing the behavior of shear links in eccentrically braced frames. Researchers attribute these past ambiguities to the failure mode of the links, as the maximum force developed in the link is proportional to the rotation capacity and, consequently, its failure mechanism. To address some of these previous uncertainties, this study examined the failure mode of short and very short shear links made from ASTM A992 steel. For this purpose, a parametric study was conducted using the finite element software ABAQUS, considering the effects of local buckling, cumulative damage under cyclic loading, and the influence of crack initiation and propagation on the reduction of strength and stiffness. According to the results, the code provisions lead to conservative outcomes (by more than 40%) for the rotation capacity of shear links, especially very short shear links. Thus, one of the main reasons for the occurrence of a large overstrength factor in shear links is their rotation capacity exceeding 0.08, which leads to strain hardening in the steel material and the development of forces greater than the plastic shear strength of the section. Furthermore, examining the failure mode of the links showed that, with an increase in web slenderness, the location of damage initiation and tearing shifts away from the stiffener-to-web connection and moves towards the center of the web panel. Additionally, in short shear links, particularly in models with smaller link length ratios, failure typically begins with vertical cracks near the stiffener and then propagates at the end of the stiffener into the link web. However, in very short shear links with smaller length ratios, web tearing occurs at the intersection of the flange and web.

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Sharif Journal of Civil Engineering

Articles in Press, Accepted Manuscript
Available Online from 12 March 2025

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