Experimental Investigation of Dynamic Behavior of RC Frame Strengthened with Buckling-Restrained Bracing

Abstract

This paper presents the results of an investigation of the dynamic behavior of a reinforced concrete frame that was strengthened by a buckling-restrained brace (BRB). The behavior of this frame was benchmarked against a control frame without strengthening. Both frames were tested concurrently on a shake table using the acceleration time-history record from the 1995 Kobe earthquake. The BRB-strengthened frame was additionally subjected to two levels of a synthetic time-history record to observe its behavior under severe ground shaking. The stiffness of the BRB-strengthened frame increased by 70% relative to the control frame. Furthermore, the cracked BRB-strengthened frame retained approximately 80% higher stiffness compared with the cracked control frame at an applied peak ground acceleration (PGA) of 0.679g. Conversely, the lateral story drift of the BRB-strengthened frame was 46% less compared with the control frame at this level of acceleration. The control frame failed by concrete crushing at base of the columns at PGA of 0.679g after yielding of the longitudinal reinforcing bars. The dissipation of hysteretic energy for the control frame reached a maximum at 0.435g, whereas the BRB-strengthened frame exhibited high strength capacity without any marked change in stiffness at 0.679g.