ABSTRACT
The first attempt was standardized the performancebased design approaches by Federal Emergency Management Agency (FEMA) that sponsored the development of national guidelines for the seismic retrofit of buildings; ATC-33 project (1992). Displacementbased design (DBD) as a simplified approach of performance based-design (PBD) was proposed initially for bridges (Kowalsky et al. 1995). These two approaches have been used interchangeably, because performance objects can be related to the level of damages to the structure which can be expressed in term of displacement or drift. The approach was adopted by Structures Engineering Association of California (SEAOC) to design new buildings (2000) on the basis of pushover analysis. In current paper brace elements of RC frames design based on strength and performance level. The static nonlinear pushover analysis was performed because it may provide much of the needed information. According to pushover analysis method predetermined load applied and gradually increased until the displacement of roof reaches to target displacement. The drift distributions of retrofitted frames were evaluated. Formation of plastic hinges and their performance levels were investigated.
