Analytical Study of Steel Braced RC Frame Systems : Verification and Application

The large displacements and weak lateral stiffness of the reinforced concrete (RC) frame, it’s one of the problems in this system when subjected to lateral load. In order to solve this problem, many suggestions of the bracing systems have been proposed. Eccentrically braced frames (EBF) and concentrically braced frames (CBF) have become a common reasonable form of the lateral load resisting steel bracing system. In this paper the effect of different types of steel brace system were investigated on the behavior of reinforced concrete frame subjected to lateral loads. SAP2000 program was used to pushover analysis and verified the experimental results, additionally the systems of CBF, EBF, X-braced, S-braced and V-braced were studied. The ductility of the RC frame was studied for these types of steel bracing, and the ductility of steel braced reinforced concrete frame was investigated by proposing an another steel cross-section used for bracing. Bracing systems of reinforced concrete frame increased the load capacity of lateral loads by a factor of 2.63,1.93,2.13,1.58, 3.60, 3.17 and 2.76 for CBF, EBF (0.4), EBF (0.3), EBF (0.5), X-braced, S-braced and V-braced respectively. The ductility was reduced when using the systems of CBF, EBF, X-braced, S-braced and V-braced with the two equal angles section. The ductility of the X-braced frame can be increased by using a solid section and I-section to factor of 5.24 and 4.70 respectively compared to the two equal angles section. The area of the steel section used for X-braced frame system effects on the load capacity and ductility.