Investigation of the Response Modification Factor of Frames Equipped with Eccentric Buckling Restrained Braces based on Performance Levels

Subject Areas : Analysis of Structure and Earthquake

Vahid  Saberi ¹ (Assistant Professor, Department of Civil Engineering, University of Eyvanekey, Semnan, Iran)
hamid  saberi ² (department of civil engineering, university of eyvanekey, semnan, iran)
Abbasali  Sadeghi ³ (Islamic azad university< Mashhad branch, Mashhad, Iran.)
Seyede Vahide  Hashemi ⁴ (Department of Civil Engineering, Engineering Faculty, Sistan and Baluchestan University, zahedan, Iran)

Received: 2019-12-28 Accepted : 2020-08-17 Published : 2020-08-22

Keywords: Response modification factor, Performance Levels, Eccentric Buckling Restrained Brace, Nonlinear Incremental Dynamic Analysis, Nonlinear Static Pushover Analysis,

Abstract :

Structural response modification factor refers to a coefficient that indicates the energy absorption capacity of the structure in the inelastic region. By using it, the shear force of the structural design is reduced by several times. In this research, the response modification factor of frames equipped with eccentric buckling restrained braces were investigated based on performance levels under the records far from the fault. In this research, three 3, 6, and 10-story  frames with eccentric buckling restrained braces were designed using ETABS software and then SeismoStruct software was applied in order to perform  nonlinear static pushover analysis and incremental dynamic analysis (IDA). In IDA analysis, the intensity parameter corresponding to (PGA) and the damage index corresponding to the maximum relative displacement of the floors (MIDR) were considered and the two performance levels of life safety (LS) and collapse prevention (CP) were investigated. The results presented that the collapse prevention performance limit was about 30 to 35 percent higher than response modification factor corresponding to the life safety performance limit, which means that the response modification factor of safety life limit can be increased by 30 percent in order to be used for structural design at the functional level of collapse prevention.