Development of efficiency index for steel moment frames with Self-Centering Connections

Abstract

Traditional earthquake-resistant systems are dependent on the inelastic response of the building members. These systems experience significant residual displacements after major earthquakes due to seismic energy distribution all over the building and make their repair uneconomical. Self-Centering systems in steel frame buildings omit residual displacements and concentrate building damage on Self-Centering connection and reduce the cost of repair. Due to the dispersion of the response of Self-Centering systems against different earthquakes, it is necessary to determine an index to control sensitivity of these systems against various records. In this paper, developing an efficiency index of steel moment frame systems with Self-Centering connections using the dispersion index's methodology is discussed. After performing the time history dynamic analyses of two steel buildings with 3 and 9 floors, six types of self-centering connections for each frame with seven dispersion indices were evaluated. Decreased dispersion of responses indicate that the system is more efficient. Among these, under the optimization of indices, it is tried to select an index with a better performance which resulted to CV index (coefficient of variation). Finally, the structure with the least dispersion of responses is selected from the viewpoint of efficiency. The selected model of this research for 3 and 9 story buildings is model M5 which is the fifth model of Moradi models.*

Keywords

• self-centering
• efficiency index
• posttensioned
• index of dispersion
• residual response