Improving seismic performance of portal frame structures with steel curved dampers

Abstract There are several methods available in regard to the improvement of the seismic performance of steel structures; moment-resisting frames and dampers are significantly used in this field, which has had a revolutionary impact these years. This paper is focused on using steel curved dampers (SCD) systems in studying the structural behavior of steel portal frames. Five dampers with the same length and thickness, yet with different angles and eccentricities, had been used in the pitched roof symmetric and mono-pitch portal frames. Series of cyclic loading were imposed on the frames equipped with various curved dampers to assess their impacts on steel portal frames. All these models were designed and analyzed by the finite element method. The final results demonstrate that by using a damper with a smaller angle, higher frame strength occurs. Hence from all five dampers (30°, 60°, 75°, 90°, and 120°), the most effective one on increasing both energy dissipation and frame strength in pitched roof symmetric portal frame and mono-pitch portal frame was the damper with a 30° and 60° angle respectively. It was also observed that there were significant improvements in the seismic performance of both types of portal frames by utilizing proposed SCD.