Fragility assessment of buckling-restrained braced frames under near-field earthquakes

Ghowsi, Ahmad Fayeq; Sahoo, Dipti Ranjan

doi:10.12989/scs.2015.19.1.173

Cited by 30 publications

(4 citation statements)

References 6 publications

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“…Thus the damages in the main beams and columns and the inter-story drifts of structures can be significantly controlled in the BRB frames (BRBFs). But experimental [2][3][4][5] and numerical [6][7][8][9][10] investigations have also shown that relatively high post-earthquake residual deformations may be exhibited in the BRBFs under significant seismic loadings. The cost of retrofitting and rehabilitating the post-earthquake structures to make them reusable was significantly increased due to the excessive residual deformations [11,12].…”

Section: Introductionmentioning

confidence: 99%

Cyclic behavior of superelastic SMA cable and its application in an innovative self-centering BRB

Shi¹,

Qian²,

Kang³

et al. 2021

Smart Mater. Struct.

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This paper presents an innovative self-centering buckling-restrained brace (SC-BRB) composed of a shape memory alloy (SMA) cables based self-centering system and an all-steel BRB. This study commences with cyclic tests on individual SMA cable to understand the influence of annealing schemes and pre-tension procedures on their fundamental mechanical properties, such as strength, stiffness, self-centering capability, energy dissipation, as well as their degradation of the properties during cyclic loading. Based on the test results, the desired annealing scheme and training procedure for the SMA cables in the proposed SC-BRB were presented. The configuration and working principle of the proposed SMA-cables-based SC-BRB were subsequently described, followed by theoretical studies on hysteretic models of the proposed brace. Numerical simulations and parametric studies were carried out to investigate the mechanical performance of the proposed SC-BRB. The results show that the investigated SMA cable can reasonably scale up the satisfactory properties of the SMA wire. The initial elastic stiffness and the 'residual' self-centering force strength of the SMA cables, which are essential for the proposed SC-BRB application, can be greatly enhanced by inflicting certain pre-stress. The initial strain and area ratio of the pre-tensioned SMA cables are suggested to be designed as about 2.5% and in the range of 60%-71.4%, respectively, to achieve appropriate energy dissipation, residual deformation, and material cost of the proposed SC-BRB.

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Section: Introductionmentioning

confidence: 99%

Cyclic behavior of superelastic SMA cable and its application in an innovative self-centering BRB

Shi¹,

Qian²,

Kang³

et al. 2021

Smart Mater. Struct.

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“…Extensive numerical study has been conducted to verify potential of BRBs to improve the seismic response. [8][9] The length of BRB core has substantial effect on its overall behaviour. The moderate length BRB can efficiently dissipate energy [10].…”

Section: Introductionmentioning

confidence: 99%

Finite Element Parametric Studies on Buckling Restrained Brace

S.¹,

Shete²,

Madhekar³

et al. 2022

ASPS Conf. Proc.

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Concentric Braced Frame (CBF) is an efficient lateral load resisting system. It adds stiffness and strength to the structural system. However, the repeated failures of concentric braces in the past earthquakes has raised concern of its overall seismic performance and ultimate deformation capacity. Buckling Restrained Brace (BRB) is becoming popular energy dissipation device in the field of seismic resistant steel structures. BRB absorbs substantial amount of energy during cyclic performance. By preventing the buckling of the brace, a symmetric and stable hysteresis curve of BRB is achieved, as it dissipates high amount of energy in every single cycle. In the present research work, numerical modelling, and prediction of cyclic response of concrete BRB is presented. The numerical model is validated by comparing the results with the previous experimental work. Numerical simulations have been performed using the finite element software ABAQUS. The yielding core length is varied from 1m to 3 m, and the coefficient of friction is varied from 0 to 1. The parametric study is carried out to investigate the influence of yielding core length and coefficient of friction on the hysteretic performance of concrete BRB. The performance of all the numerical models is accessed by comparing their hysteretic response and the compression adjustment factor. With increasing the friction coefficient between the steel core and the concrete, an unsymmetrical hysteretic response is observed, with reduction in energy dissipation. Axial stiffness of short length BRB is found to be higher, as compared to the longer length. From the parametric study, it is revealed that the length of the yielding core and friction impact the cyclic response of BRBs

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“…It is found from the research on seismic performance that buckling-restrained braces can effectively dissipate the seismic energy under earthquakes, reduce structural response, and provide additional stiffness and damping for the building structure. e buckling-restrained brace can enter the elastoplastic state before the main structure, which improves the seismic ultimate bearing capacity of the overall structure [7,[30][31][32][33][34][35][36]. Some previous achievements have been made in the research and analysis of buckling-restrained bracing structure, which promotes the application and development for building systems.…”

Section: Introductionmentioning

confidence: 99%

Shaking Table Test for Evaluating the Seismic Performance of Steel Frame Retrofitted by Buckling‐Restrained Braces

Wang

Shao

Zhao

et al. 2021

Shock and Vibration

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To investigate the seismic performance of buckling-restrained braces under the earthquake action, the shaking table test with a two-story 1/4 scale model is carried out for the ordinary pure steel frame and the buckling-restrained bracing steel frame with low-yield-point steel as the core plate. The failure modes, dynamic characteristics, acceleration response, interstory drift ratio, strain, shear force, and other mechanical properties of those two comparative structures subjected to different levels of seismic waves are mainly evaluated by the experiment. The test results show that under the action of seismic waves with different intensities, the apparent observations of damage occur in the pure frame structure, while no obvious or serious damage in the steel members of BRB structure is observed. With the increase in loading peak acceleration for the earthquake waves, the natural frequency of both structures gradually decreases and the damping ratio gradually increases. At the end of the test, the stiffness degradation rate of the pure frame structure is 11.2%, while that of the buckling-restrained bracing steel frame structure is only 5.4%. The acceleration response of the buckling-restrained bracing steel frame is smaller than that of the pure steel frame, and the acceleration amplification factor at the second story is larger than that at the first story for both structures. The average interstory drift ratios are, respectively, 1/847 and 1/238 for the pure steel frame under the frequent earthquake and rare earthquake and are 1/3000 and 1/314 for the buckling-restrained bracing steel frame, which reveals that the reduction rate of lateral displacement reaches a maximum of 71.71% after the installation of buckling-restrained brace in the pure steel frame. The strain values at each measuring point of the structural beam and column gradually increase with the increase of the peak seismic acceleration, but the strain values of the pure steel frame are significantly larger than those of the buckling-restrained bracing steel frame, which indicates that the buckling-restrained brace as the first seismic line of defense in the structure can dramatically protect the significant structural members. The maximum shear force at each floor of the structure decreases with the increase in height, and the shear response of the pure frame is apparently higher than that of the buckling-restrained bracing structure.

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Fragility assessment of buckling-restrained braced frames under near-field earthquakes

Cited by 30 publications

References 6 publications

Cyclic behavior of superelastic SMA cable and its application in an innovative self-centering BRB

Cyclic behavior of superelastic SMA cable and its application in an innovative self-centering BRB

Finite Element Parametric Studies on Buckling Restrained Brace

Shaking Table Test for Evaluating the Seismic Performance of Steel Frame Retrofitted by Buckling‐Restrained Braces

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