Document Type : Research Article
Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
School of Civil Engineering, University of Tehran. P.O. Box 11155-4563, Tehran, Iran
The advantages of implementing metallic yielding dampers including increased ductility and damping of the structure, easy fabrication and installation at sites, inspectability and easy access to the materials used for manufacturing, have caused daily increase of using these dampers in seismic retrofitting of structures. The main objective of this research is to introduce a new elliptical shaped metallic damper for reducing the responses and upgrading the seismic performance of existing steel structures. Considering the effect of geometrical parameters of elliptical damper on the seismic behavior of retrofitted buildings, a precise numerical investigation of the damper with different diameter to thickness ratios and also different dimensions and placements of shear diaphragm has been performed. To perform the seismic evaluation of the proposed damper in retrofitting the structures, three 3, 9 and 20-story benchmark structures were used. Also, to investigate the results of the analyses for different seismic states in the nonlinear time-history analyses, the corresponding near and far field earthquake records were considered. In this paper, modeling and analysis of the benchmark structures with added dampers were performed in ABAQUS and SAP2000 software and the seismic behavior of retrofitted buildings was examined. The numerical results indicate good seismic performance of proposed metallic damper in dissipating earthquake energy and reducing the seismic response of retrofitted buildings leading to stable hysteresis curves with limited losses in strength and stiffness. Furthermore, on average, maximum drift of the floors of the 3, 9 and 20-story benchmark structures are reduced by 71, 78 and 51%, respectively.