Out-of-Plane Stability of Buckling-Restrained Braces

Abstract

Large-scale shake table tests were performed at E-Defense to examine the out-of-plane stability of bucklingrestrained braces (BRBs). Two planar specimens were subjected repeatedly to a near-fault ground motion with increasing magnitude. The specimens comprised a single-bay, single-story steel frame and a pair of BRBs placed in a chevron arrangement. The specimens were not braced at the brace-to-beam intersection in order to produce a condition where the BRBs were susceptible to out-of-plane instability. Standard BRBs were used in Specimen 1, while unique BRBs with a flexible segment at each end of the steel core were used in Specimen 2. Specimen 1 exhibited excellent behavior. As predicted by a simple buckling model, Specimen 2 failed due to out-of-plane buckling that involved severe kinking deformation at both ends of the steel core and severe twisting of the beam. The buckling model may be used to estimate minimal bracing requirements for steel frames with chevron BRBs.

Out‐of‐plane stability of buckling‐restrained braces including moment transfer capacity

“…Zao et al [9,10] investigated the stability conditions of BRBs with pin-ended connections. Hikino et al [11] carried out shaking table tests on BRB frames, and Okazaki et al [12] suggested stiffness requirements for gusset plates under one-sided buckling considering the loss of restrainer moment transfer capacity and confirmed the requirements by the test results. In addition, the stiffness and strength requirements at connections have also been investigated through several other BRB frame tests [13][14][15][16][17].…”

“…Hikino et al . carried out shaking table tests on BRB frames, and Okazaki et al . suggested stiffness requirements for gusset plates under one‐sided buckling considering the loss of restrainer moment transfer capacity and confirmed the requirements by the test results.…”

Buckling-Restrained Bracing System with Ultra-High-Performance Fiber Concrete

“…Due to the mechanical difficulties and the need to keep to the design process, mainly empirical and semi-empirical models have been proposed. Palazzo (2009) offered an analytical method for BRB rigidity requirements [12] and Hikino (2011) presented an outof-plane-deformations stability model [13]. Zhao (2012) investigated whether bracing systems affect end rotation for global stability designs [14] and also studied the local buckling behavior of all-steel BsRBs [15].…”

Out‐of‐plane stability assessment of buckling‐restrained braces including connections with chevron configuration

“…However, the critical aspect of BRB performance requires inclusion of the connection effect in the assessment of the buckling failure mode. Takeuchi et al [1] summarized the most recent literature related to connection failure, which includes research highlights [2][3][4][5][6][7][8][9][10][11][12][13][14] and the steel structure seismic provisions [15,16]. Additionally, Lin et al [17] investigated the connection stress distribution by means of experimental testing and FEM analysis, proposing several design recommendations.…”