Post-fire performance evaluation of an innovative trapezoidal shear damper for enhancing the behavior of concentrically braced frames

Structural buildings are susceptible to both fire and earthquake events throughout their lifespan, which may occur concurrently or sequentially. Fires typically reduce a structure's stiffness and strength, and earthquakes can trigger fires, forcing structures already compromised by seismic activity to endure post-earthquake fires. This study investigates the post-fire performance of an innovative metallic trapezoidal damper, attached to the diagonal member of a concentric braced frame, through parametric and numerical analysis using the finite element method (FEM). Findings reveal that temperatures up to 200o C have minimal impact on the damper's performance. Dampers with thicker flange plates exhibit a greater reduction in structural parameters compared to those with thinner flange plates. Additionally, the reduction in structural parameters is more pronounced at lower ultimate temperatures (Tu) than at higher ones. When the capacity ratio of the web plate to the flange plate ranges from 1 to 3, structural parameters show a steeper decline, but this reduction rate decreases when the capacity ratio exceeds 3. Furthermore, the reduction rate at Tu=800oC is lower than at Tu=200oC.