Subassemblage cyclic loading test of RC frame with buckling restrained braces in zigzag configuration

Abstract

SUMMARY A new buckling restrained braced frame system is proposed for reinforced concrete building structures, which is featured by the zigzag configuration of the braces and the corresponding connection details. The connection details tend to separate the vertical and horizontal components of force imposed by the braces to be resisted by independent structural components to make the behavior of the connection easier to estimate and control. The performance of the brace connection details was evaluated through cyclic load testing on 1/2‐scale subassemblies of the proposed system, each of which consisted of a reinforced concrete part and a set of buckling restrained braces. To simplify the test control, the specimens were rotated 90° in the test and were loaded by two displacement controlled actuators. The test results show that the normal and the shear resistance of the gusset plate connection are essentially independent of each other. However, the rotation of the gusset plate with respect to the beam‐to‐column joint may result in nonuniform force distribution of the anchor bolts, the primary resistance for tensile force. At the same time, such rotation may also subject the concrete corbels, the primary shear resistance, to unfavorable tensile force. In addition, it is also confirmed that the buckling restrained braces performed well in the proposed system. Copyright © 2012 John Wiley & Sons, Ltd.

Experimental and Analytical Studies on a Reinforced Concrete Frame Retrofitted with Buckling-Restrained Brace and Steel Caging

“…The maximum local out-of-plane displacement was 1.5 mm, corresponding to buckling of the top gusset plate. It indicates that mechanical behavior of the gusset plate was affected by damage of the RC main frame, which agrees with the previous studies of other researchers (Ishii et al 2006;Qu et al 2013).…”

“…Qu et al (2013) pointed out that the existence of a BRB gusset plate may subject the surrounding concrete members to very complicated, and sometimes unfavorable, load conditions. They proposed a new bracing system that had BRBs arranged in a zigzag configuration to reduce the negative effects caused by the interaction between the gusset plates and the adjacent members.…”

Hybrid experimental performance of a full‐scale two‐story buckling‐restrained braced RC frame

“…In addition, no separation was observed between the CAB and RC member during all the tests, demonstrating the binding ability of the proposed connection. In comparison with the proposed connection detail, any separation occurred, between the steel gusset bracket and RC member in other connection detail using pre‐stressing rods , could reduce the stiffness of the entire frame system under the cyclic loads.…”

“…Because of the limited research to date on the implementation of BRBs in new RC construction, further studies are warranted to develop a robust system and design procedure. To the best of the authors' knowledge, the only research is the zigzag‐linked buckling‐restrained braced frame (BRBF) system , where the BRBs are arranged in a zigzag manner with adjacent BRBs sharing gusset plates attached to the side of the beam‐column joints using a post‐installed steel bracket. A new post‐tensioned concrete carpark structure using BRBs connected to massive embedded brackets at the beam‐column joints has been constructed , but this was undertaken without testing.…”

Effect of non‐moment braced frame seismic deformations on buckling‐restrained brace end connection behavior: Theoretical analysis and subassemblage tests

“…In actual applications, welded or bolted end connections ( Figure 1) are commonly used to connect the BRBs to frame gusset plates for easy construction. Previous studies showed that such rotational deformations could be comparable with the inter-story drift angle [9][10][11], which may have a negative impact on the performance of BRBs, especially the connection zone behavior. Previous studies showed that such rotational deformations could be comparable with the inter-story drift angle [9][10][11], which may have a negative impact on the performance of BRBs, especially the connection zone behavior.…”