• Title/Summary/Keyword: Buckling Restrained Brace

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Local and global buckling condition of all-steel buckling restrained braces

  • Mirtaheri, Seyed Masoud;Nazeryan, Meissam;Bahrani, Mohammad Kazem;Nooralizadeh, Amin;Montazerian, Leila;Naserifard, Mohamadhosein
    • Steel and Composite Structures
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    • v.23 no.2
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    • pp.217-228
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    • 2017
  • Braces are one of the retrofitting systems of structure under earthquake loading. Buckling restrained braces (BRBs) are one of the very efficient braces for lateral loads. One of the key needs for a desirable and acceptable behavior of buckling-restraining brace members under intensive loading is that it prevents total buckling until the bracing member tolerates enough plastic deformation and ductility. This paper presents the results of a set of analysis by finite element method on buckling restrained braces in which the filler materials within the restraining member have been removed. These braces contain core as the conventional BRBs, but they have a different buckling restrained system. The purpose of this analysis is conducting a parametric study on various empty spaces between core and restraining member, the effect of friction between core and restraining member and applying initial deformation to brace system to investigate the global buckling behavior of these braces. The results of analysis indicate that the flexural stiffness of restraining member, regardless of the amount of empty space, can influence the global buckling behavior of brace significantly.

Experimental Structural Performance Evaluation of Precast-Buckling Restrained Brace Reinforced With Engineering Plastics (공업용 플라스틱으로 보강된 비좌굴가새의 실험적 구조성능평가)

  • Kim, Yu-Seong;Kim, Gee-Chul;Kang, Joo-Won;Lee, Joon-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.3
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    • pp.43-52
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    • 2020
  • In this study, the Buckling restrained braces reinforced with engineering plastics that can compensate for the disadvantages in the manufacturing process of the existing buckling restrained brace. The proposed PC-BRB was fabricated to evaluate the reinforcement effect by carrying out a structural performance test and a full-scale two-layer frame test through cyclic loading test. As a result of PC-BRB's incremental and cyclic loading test, stable hysteresis behavior was achieved within the target displacement, and the compressive strength adjustment coefficient satisfied the recommendation. As a result of the real frame experiment, the strength of the reinforced specimen increased compared to the unreinforced specimen, and the ductility and energy dissipation increased.

Structural behavior of conventional and buckling restrained braced frames subjected to near-field ground motions

  • Guneyisi, Esra Mete;Ameen, Nali
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.553-570
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    • 2014
  • In this study, nonlinear dynamic analyses were performed in order to evaluate and compare the structural response of different type of moment resisting frame buildings equipped with conventional braces (CBs) and buckling restrained braces (BRBs) subjected to near-field ground motions. For this, the case study frames, namely, ordinary moment-resisting frame (OMRF) and special moment-resisting frame (SMRF) having two equal bays of 6 m and a total height of 20 m were utilized. Then, CBs and BRBs were inserted in the bays of the existing frames. As a brace pattern, diagonal type with different configurations were used for the braced frame structures. For the earthquake excitation, artificial pulses equivalent to Northridge and Kobe earthquake records were taken into account. The results in terms of the inter-story drift index, global damage index, base shear, top shear, damage index, and plastification were discussed. The analysis of the results indicated a considerable improvement in the structural performance of the existing frames with the inclusion of conventional and especially buckling-restrained braces.

Finite Element Model Verification of Buckling Restrained Brace With Nonlinear Behavior (비선형 거동을 하는 비좌굴가새의 유한요소모델 검증)

  • Kim, Dae-Hong;Yoo, Jung-Han
    • Journal of Korean Association for Spatial Structures
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    • v.21 no.2
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    • pp.81-88
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    • 2021
  • In this paper, nonlinear finite element analysis was conducted based on the experimental results on buckling restrained brace. The reliability of the analytical model was verified by comparing the results of experimental studies with hysteresis loop, bi-linear curve, cumulative energy dissipation capacity, and equivalent viscous damping. A valid finite element model has been secured and will be used as basic data for finite element analysis of buckling restrained braces in the future.

Hysteresis Characteristics of Buckling Restrained Brace with Precast RC Restraining Elements (조립형 프리캐스트 콘크리트 보강재를 가지는 비좌굴가새의 이력특성)

  • Shin, Seung-Hoon;Oh, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.1
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    • pp.72-84
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    • 2016
  • The conventional brace system is generally accepted as the lateral load resisting system for steel structures due to efficient story drift control and economic feasibility. But lateral stiffness of the structure decreases when buckling happens to the brace in compression, so that it results in unstable structure with unstable hysteresis behavior through strength deterioration. Buckling restrained brace(BRB) system, in which steel core is confined by mortar/concrete-filled tube, represents stable behavior in the post-yield range because the core's buckling is restrained. So, seismic performance of BRB is much better than that of conventional brace system in point of energy absorption capacity, and it is applied the most in high seismicity regions as damper element. BRBs with various shaped-sections have been developed across the globe, but the shapes experimented in Korea are now quite limited. In this study, we considered built-up type of restraining member made up of precast reinforcement concrete and the steel core. we experimented the BRB according to AISC(2005) and evaluated seismic performances and hysteresis characteristics.

Experimental Investigation of The Lateral Retrofitting Effect of FRP Sheet and Buckling-restrained Braces for Beam-Column Joints (FRP Sheet와 비좌굴 가새를 적용한 보-기둥 접합부의 횡방향 보강효과에 관한 실험적 연구)

  • Byon, Eun-Hyuk;Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Earthquake Engineering Society of Korea
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    • v.15 no.1
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    • pp.49-56
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    • 2011
  • The strengthening effect of CFRP sheet and AFRP sheet with buckling-restrained brace for Beam-Column joints under constant axial and cyclic lateral loading is evaluated experimentally in this paper. Six test specimens were constructed. The main test parameters included the FRP Sheet and Buckling-restrained braces. The results of the tests were analyzed by focusing on their mode of failure, maximum load, ductility indexes, and energy dissipation capacity. Test results indicated that CFRP Sheet with the buckling-restrained brace system significantly increased the strength and stiffness of the specimen and that it was the most adequate retrofitting method.

Application of Buckling Restrained Braces in a 50-Storey Building

  • Sy, Jose A.;Anwar, Naveed;Aung, Thaung Htut;Rayamajhi, Deepak
    • International Journal of High-Rise Buildings
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    • v.3 no.1
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    • pp.81-87
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    • 2014
  • The use of Buckling Restrained Braces (BRB) for enhancing the performance of the buildings is gaining wider acceptance. This paper presents the first application of these devices in a major high-rise building in the Philippines. A 50-storey residential reinforced concrete building tower, with ductile core wall, with BRB system is investigated. The detailed modeling and design procedure of buckling restrained brace system is presented for the optimal design against the two distinct levels of earthquake ground motions; serviceable behavior for frequent earthquakes and very low probability of collapse under extremely rare earthquakes. The stiffness and strength of the buckling restrained brace system are adjusted to optimize the performance of the structural system under different levels of earthquakes. Response spectrum analysis is conducted for Design Basis Earthquake level and Service level, while nonlinear time history analysis is performed for the most credible earthquake. The case study results show the effectiveness of buckling restrained braces.

Multi-material core as self-centering mechanism for buildings incorporating BRBs

  • Hoveidae, Nader
    • Earthquakes and Structures
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    • v.16 no.5
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    • pp.589-599
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    • 2019
  • Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without major degradation of capacity under severe seismic ground motions. One of the weakness points of a standard buckling restrained braced frame is the low post-yield stiffness and thus large residual deformation under moderate to severe ground motions. This phenomenon can be attributed to low post-yield stiffness of core member in a BRB. This paper introduces a multi-core buckling restrained brace. The multi-core term arises from the use of more than one core component with different steel materials, including high-performance steel (HPS-70W) and stainless steel (304L) with high strain hardening properties. Nonlinear dynamic time history analyses were conducted on variety of diagonally braced frames with different heights, in order to compare the seismic performance of regular and multi-core buckling restrained braced frames. The results exhibited that the proposed multi-core buckling restrained braces reduce inter-story and especially residual drift demands in BRBFs. In addition, the results of seismic fragility analysis designated that the probability of exceedance of residual drifts in multi-core buckling restrained braced frames is significantly lower in comparison to standard BRBFs.

An Analytical Study on the Performance of Buckling Restrained Brace Reinforced with Steel Plate (강판으로 보강된 비좌굴가새의 성능에 대한 해석적 연구)

  • Kim, Dae-Hong;Kim, Hyeok-Soo;Yoo, Jung-Han
    • Journal of Korean Association for Spatial Structures
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    • v.22 no.1
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    • pp.51-57
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    • 2022
  • In this paper, based on the finite element analysis model verified in previous studies, a new model of a buckling restrained brace reinforced with a steel plate was proposed. A design formula was proposed for the new model to dissipate energy without buckling the steel core under load protocol, and the performance of the model satisfying the design formula was evaluated by comparing it with the previous model through the results of hysteresis loop, bi-linear curve, cumulative energy dissipation capacity, and equivalent viscous damping.

Analytical Estimation on the Seismic Performance of Hybrid Buckling-Restrained Braces (하이브리드 비좌굴가새의 내진성능에 대한 해석적 평가)

  • Kim, Do-Hyun;Kim, Young-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.14 no.3
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    • pp.57-65
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    • 2014
  • In order to improve the wind performance of buckling-restrained braces (BRBs), Hybrid buckling-restrained braces (H-BRBs) have been studied in Korea. The seismic performance of H-BRBs is different according to the action of VE damper. In this study, the nonlinear time history analyses have been performed on the parameters such as brace types and input earthquakes. The results of the study suggest that H-BRBs meet the BRB's requirement of ANSI/AISC 341-10 only if VE damper is not working during an earthquake.