مشخصات پژوهش

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.