S.A. Hadigheh - Department of Civil Engineering, Yazd University, Yazd, Iran
M. Foroughi - Assist. Prof., Div. of Civil Engineering, Faculty of Engineering, Yazd University, Yazd, Iran

According to recent earthquakes, non-ductile reinforced concrete frames suffer from excessive damages and cause loss of life. Concentric bracing systems have been used to strengthen and rehabilitate weak RC structures during past decade. In this article, the seismic behavior of an ordinary moment resisting RC frame strengthened with steel braces has been investigated. For this purpose, nonlinear static analysis (pushover) was carried out on three frames with different height, three, six and nine stories. Seismic behavior factor (R) of plain and retrofitted frames is obtained from pushover curve and a comparison has been carried out for different height. In addition, according to base shear-top displacement curve, ductility of frames is determined. Finally, performance levels of frames are obtained using the capacity spectrum method of ATC-40. Results show that strengthening with steel braces can increase the performance point of RC frames.

RC frame, Steel brace system, Pushover, Ductility, Performance Levels