Keywords
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Shear link, Cyclic behavior, Post-fire conditions, Over strength factor, Shear strength, Energy dissipation capacity
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Abstract
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After a fire, structural elements are cooled with air or water, affecting the reliability of lateral bracing systems during
subsequent earthquakes—a topic largely unexplored. This study investigates the post-fire seismic performance of short and
very short links in eccentrically braced frames. To this aim, a robust finite element model of shear links made of ASTM
A992 steel was developed and validated against experimental data in terms of strength and stiffness degradation under
local buckling, cumulative damage, and extreme temperature exposure. The results indicated that the seismic performance
of shear links is significantly affected by high temperatures, particularly when followed by water cooling, compared to
natural air cooling. The strain hardening factor of 1.25 recommended by AISC 341–22 drastically underestimates (by
12–54%) the maximum shear force developed in fire-damaged shear links, suggesting the need for potential revisions in
design codes to account for fire-induced material degradation. Fire exposure up to 600 °C followed by air cooling has
almost no effect (less than 5%) on the energy dissipation capacity of shear links. However, shear links subjected to the
same high temperature but cooled through water splashing show approximately a 25% reduction in energy dissipation
capacity. Furthermore, the cooling method has a more severe impact than high temperatures on the energy dissipation
capacity of the links. These findings emphasize the importance of integrating post-fire cooling effects into performance-based seismic design guidelines to ensure structural safety in fire-affected buildings.
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