Mechanical properties and displacement capacity of welded-plate flexural yielding dampers

Replaceable hysteretic steel dampers can be installed at the ends of diagonal braces to provide passive energy dissipation in frame-type structures. These dampers must satisfy both strength and displacement requirements. Previous studies have primarily focused on small-scale component testing, with limited investigation into the performance of large-scale dampers, particularly through sub-assemblage testing. This paper presents the findings of a combined experimental and numerical study on the mechanical properties and displacement capacity of welded-plate flexural yielding dampers. The experimental program was carried out in two phases: the first involved component testing of five specimens, while the second involved sub-assemblage testing of two specimens. Key variables included the number of yielding plates, plate length, plate thickness, and steel grade. Results from the first phase demonstrated that welded-plate flexural yielding dampers can achieve yield and ultimate resistances of 626 kN and 891 kN, respectively, with deformation capacities exceeding 40 mm. In the second phase, sub-assemblage tests showed that braces equipped with welded-plate flexural yielding dampers could accommodate story drifts of 2.63 % with single dampers and 5.5 % with dual dampers. Finite element analysis was used to simulate the behavior of the specimens and to develop a failure criterion for damper design. An expression was developed to calculate displacement capacity based on geometric variables. Both experimental and numerical results confirm the suitability of welded-plate flexural yielding dampers for seismic applications, offering a reliable and efficient energy dissipation mechanism for braced frame structures.