Enhancing The Seismic Behavior of Concentrically Braced Frames Using An Innovative Steel Ring Damper

Document Type : Original Article

Authors

Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract

Although Concentric braces have high stiffness and strength, they develop undesirable energy dissipation capacity and ductility due to the bracing member buckling under cyclic loading. Using steel dampers is one of the appropriate methods to improve the braces behavior. Therefore, in this paper an innovative steel ring damper is introduced to improve the performance of conventional ring dampers. In order to study the behavior of the proposed damper, first the verification of the experimental specimen was performed, and then the hysteretic behavior of the proposed damper was investigated using Abaqus. The hystereretic curves demonstrate that the proposed damper has a stable and symmetric hysteresis curve without stiffness and strength degradation. Therefore, it can be used as a ductile member. Also, in comparison with the conventional ring damper, the energy dissipation and stiffness of the proposed damper are on average 3.7 and 4.3 times greater, respectively. To overcome the disadvantages of concentric braces, the proposed damper was installed on the diagonal brace. The results indicate that the proposed damper, with its stable and symmetric hysteretic behavior, has enhanced the hysteresis curve of the concentric braces and can play a role of a structural fuse due to the concentration of most of the damage. Finally, a nonlinear time-history analysis was conducted to compare the concentrically braced frame with and without a damper. The results show that the proposed damper can decrease the maximum base shear about 94% on average. Also, adding the proposed damper decreases the story drift of some stories.

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