scholarly journals Numerical Investigation of Seismic Response of Hybrid Buckling Restrained Braced Frames

2018 ◽  
Author(s):  
Nader Hoveidae
Keyword(s):  
Stainless Steel ◽  
Ground Motions ◽  
Residual Deformation ◽  
Core Material ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
The Core ◽  
Buckling Restrained Brace ◽  
Buckling Restrained Braces ◽  
Buckling Restrained Braced Frames

The 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 related to the low post-yield stiffness of the core segment in comparison to its elastic stiffness. This paper investigates the application of stainless steel as the core material in a hybrid buckling restrained brace. The “hybrid” term arises from the use of more than one core component with different steel materials, including high strength high-performance steel and stainless steel (304L) with high strain hardening in the core of buckling restrained brace. Nonlinear dynamic time history analyses were conducted on a variety of diagonally braced frames with different heights, in order to compare the seismic performance of standard (non-hybrid) and hybrid buckling restrained braced frames. The results showed that the proposed hybrid buckling restrained braces reduce the inter-story and specially the residual drift demands in buckling restrained braced frames.

Experimental Tests for Pre-Qualification of a Set of Buckling-Restrained Braces

2018 ◽  
Vol 763 ◽  
pp. 450-457 ◽  
Author(s):  
Aurel Stratan ◽  
Ciprian Ionut Zub ◽  
Dan Dubină
Keyword(s):  
Experimental Tests ◽  
Experimental Program ◽  
Design Parameters ◽  
Gap Size ◽  
Braced Frames ◽  
The Core ◽  
Cyclic Behaviour ◽  
Structural Fuse ◽  
Buckling Restrained Braces ◽  
Buckling Restrained Braced Frames

Buckling restrained braces are increasingly used as structural fuse elements due to their stable and quasi-symmetric cyclic behaviour and capacity to dissipate a large amount of energy. However, a wider adoption of buckling restrained braced frames is often precluded by the proprietary character of most buckling restrained braces, need for their experimental qualification and sometimes lack of experience of designers. To overcome these problems, a set of typical buckling restrained braces were developed in view of their pre-qualification. Both "conventional" and "dry" devices were considered, with capacities corresponding to typical steel multistorey buildings in Romania. Detailing of buckling restrained braces aimed at investigating the core aspect ratio, gap size, strength of the buckling restraining mechanism, and the unbonding material. The paper presents the results of the experimental program, and recommended design parameters of qualified specimens.

Inelastic behavior of smart recentering buckling-restrained braced frames with superelastic shape memory alloy bracing systems

2012 ◽  
Vol 227 (4) ◽  
pp. 806-818 ◽  
Author(s):  
Jong Wan Hu ◽  
Dong Ho Choi ◽  
Dong Keon Kim
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Strains ◽  
Self Healing ◽  
Inelastic Behavior ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Buckling Restrained Brace ◽  
Buckling Restrained Braced Frames ◽  
Brace Frames

Buckling-restrained braced frames are steadily replacing concentrically braced frames because buckling-restrained brace can yield without buckling when subjected to both tension and compression. Though buckling-restrained brace frames are being widely used as framing structures for construction in high seismicity areas, it is shown that at large strains, a considerable amount of permanent deformation is produced at the support connector between the brace and the frame. This drawback can be overcome by providing recentering capabilities to the braced frame system. By applying the concept of a recentering system to the design of buckling-restrained brace frames, we developed braced frames that incorporate buckling-restrained braces with superelastic shape memory alloy end-support connectors. Owing to the recentering capability, shape memory alloy materials have been used in the place where large deformation may feasibly occur. The primary advantages of the innovative braced frames proposed herein are verified through nonlinear pushover analyses. Analytical frame models are developed to estimate theultimate and residual inter-story drifts. The analysis results suggest that buckling-restrained brace frames with superelastic shape memory alloy bracing systems are more effective in controlling residual inter-story drifts than those with conventional steel bracing systems owing to the inherent self-healing characteristics of superelastic shape memory alloys.

Seismic performance evaluation of multi-story CBFs equipped with SMA-friction damping braces

2021 ◽  
pp. 1045389X2098700 ◽  
Author(s):  
Canxing Qiu ◽  
Jiawang Liu ◽  
Jun Teng ◽  
Zuohua Li ◽  
Xiuli Du
Keyword(s):  
Strain Hardening ◽  
Ground Motions ◽  
Residual Deformation ◽  
Martensite Phase ◽  
Friction Damper ◽  
Concentrically Braced Frames ◽  
Friction Damping ◽  
Friction Mechanism ◽  
Building Collapse ◽  
Response Characteristics

Shape memory alloys (SMAs) gained increasing attentions from the perspective of seismic protection, primarily because of their excellent superelasticity, satisfactory damping and high fatigue life. However, the superelastic strain of SMAs has an upper limit, beyond which the material completes the austenite to martensite phase transformation and is followed by noticeable strain hardening. The strain hardening behavior would not only induce high force demand to the protected structures, but also cause unrecoverable deformation. More importantly, the SMAs may fracture if the deformation demand exceeds their capacity under severe earthquakes. In the case of installing SMA braces (SMABs) in the multi-story concentrically braced frames (CBFs), the material failure would lead to the malfunction of SMABs and this further causes building collapse. The friction mechanism could behave as a “fuse” through capping the strength demand at a constant level. Therefore, this paper suggests connecting the SMAB with a friction damper to achieve a novel brace, i.e. the SMA-friction damping brace (SMAFDB). A proof-of-concept test was carried out on a homemade specimen and the test results validated the novel brace behaves in a desirable manner. In addition, to explore the seismic response characteristics of the SMAFDB within structures, a six-story CBF equipped with SMAFDBs was designed and compared against those incorporated with SMABs or friction damping braces (FDBs) at the frequently occurred earthquake (FOE), design basis earthquake (DBE) and maximum considered earthquake (MCE). The comparative results show the SMAFDB is superior to the counterparts. Under the FOE and DBE ground motions, the SMAFDBs successfully eliminated residual deformations as the SMABs do, and achieved identical maximum interstory drift as the FDBs. Under the MCE ground motions, the SMAFDBs not only well addressed the brace failure problem that was possibly encountered in the SMABs, but also better controlled residual deformation than the FDBs.

Ductility Enhancement in Reinforced Concrete Structure with Buckling Restrained Braced Frames

2016 ◽  
Vol 847 ◽  
pp. 281-289
Author(s):  
Erkan Senol ◽  
Ismail Kose ◽  
Bilge Doran ◽  
Pelin Elif Mezrea ◽  
Bulent Akbas
Keyword(s):  
Reinforced Concrete ◽  
Pushover Analysis ◽  
Design Procedure ◽  
Braced Frames ◽  
Base Shear ◽  
Moment Frames ◽  
Concentrically Braced Frames ◽  
Capacity Curve ◽  
Concentrically Braced ◽  
Buckling Restrained Braced Frames

Adding braces to moment frames is considered to be quite an efficient technique for increasing the global stiffness and strength of the structure. It has not only been used in steel moment frames, but also in reinforced concrete (RC) moment frames in recent years. It certainly can increase the energy absorption capacity of structures and also decrease the demand imposed by seismic ground motions. Steel braces are anchored firmly to boundary beams and columns. They are modeled as truss elements and increase earthquake resistance of the building. Buckling restrained braced frames (BRBFs) in which members yield under both tension and compression without significant buckling have been used in recent years in order to ensure the desired seismic performance of special concentrically braced frames. BRBFs are similar to the special concentrically braced frames in that seismic accelerations are resisted by a building-frame members and diagonal braces whereas the design procedure is different. BRBs should be designed to permit ductile yielding both in compression and tension. In this paper, flat-slab RC building with two different configurations of buckling restraint braces (BRBs) is studied. The buildings have 4-storey with 5 bays in both X-and Y-directions and have been designed according to Turkish Specification of Reinforced Concrete Design (TS 500). In order to explore overall behavior up to failure and lateral load resisting capacities for these buildings, nonlinear static analyses have then been performed using SAP 2000-V14.1. Pushover analysis under constant gravity loads and monotonically increasing lateral forces during an earthquake until a target displacement is reached is generally carried out as an effective tool for performance based design. The major outcome of a pushover analysis is the capacity curve which shows the base shear vs. the roof displacement relationship and represents the overall performance of the building. The results of the analyses are presented in terms of capacity curve and energy dissipation.

scholarly journals On the European Norms of Design of Buckling Restrained Braced Frames

2017 ◽  
Vol 11 (1) ◽  
pp. 513-530 ◽  
Author(s):  
Ádám Zsarnóczay ◽  
Tamás Balogh ◽  
László Gergely Vigh
Keyword(s):  
Seismic Design ◽  
Structural Reliability ◽  
Design Procedure ◽  
Material Model ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Reliability Indices ◽  
Buckling Restrained Braces ◽  
Buckling Restrained Braced Frames ◽  
Ground Motion Records

The application of buckling restrained braced frames is hindered in Europe by the absence of a standardized design procedure in Eurocode 8, the European seismic design standard. The presented research aims to develop a robust design procedure for buckling restrained braced frames. A design procedure is proposed by the authors. Its performance has been evaluated for buckling restrained braced frames with two-bay X-brace type brace configurations using a state-of-the-art methodology based on the recommendations in the FEMA P695 document. A special numerical material model was developed within the scope of this research to represent the behavior of buckling restrained braces more appropriately in a numerical environment. A total of 24 archetype designs were prepared and their nonlinear dynamic response was calculated using real ground motion records in incremental dynamic analyses. Evaluation of archetype collapse probabilities confirms that the proposed design procedure can utilize the advantageous behavior of buckling restrained braces. Resulting reliability indices suggest a need for additional regulations in the Eurocodes that introduce reasonable structural reliability index limits for seismic design.

Evaluating the Effect of Buckling-Restrained Brace Model on Seismic Structural Responses

2017 ◽  
Vol 11 (02) ◽  
pp. 1750002 ◽  
Author(s):  
Yulong Feng ◽  
Jing Wu ◽  
Chunlin Wang ◽  
Shaoping Meng
Keyword(s):  
Kinematic Hardening ◽  
Stiffness Ratio ◽  
Braced Frames ◽  
Simplified Models ◽  
Buckling Restrained Brace ◽  
Perfectly Plastic ◽  
Seismic Design Code ◽  
Structural Responses ◽  
Buckling Restrained Braced Frames ◽  
Elastic Perfectly Plastic

Numerical simulation is an important measure to study the seismic performance of buckling-restrained braced frames (BRBFs). Practically, some simplified models, such as the elastic–plastic with kinematic hardening model and the elastic perfectly-plastic model, are used to simulate the behavior of buckling-restrained brace (BRBs). To provide structural engineers the reference of errors when simplified models are used, this paper comparatively evaluates the effect of the BRB model on seismic structural responses using the OpenSees software. A comparison is made on six-storey and 16-storey BRBFs with rigid beam-to-column connections; these are designed according to Chinese seismic design code. Moreover, the effects of the post-yielding stiffness ratio of frame [Formula: see text] and the stiffness ratio of BRB to frame [Formula: see text] on the errors are specifically investigated through a parametric study of both BRBFs. The results show that the seismic response average errors of the simplified models are mostly less than 5%, which satisfies the engineering requirements.

Seismic design of buckling-restrained braced frames based on a modified energy-balance concept

2006 ◽  
Vol 33 (10) ◽  
pp. 1251-1260 ◽  
Author(s):  
Hyunhoon Choi ◽  
Jinkoo Kim ◽  
Lan Chung
Keyword(s):  
Energy Balance ◽  
Seismic Design ◽  
Response Spectrum ◽  
Design Procedure ◽  
Time History ◽  
Energy Performance ◽  
Braced Frames ◽  
Plastic Energy ◽  
Buckling Restrained Braces ◽  
Buckling Restrained Braced Frames

The conventional energy-based seismic design procedure based on the energy-balance concept was revised for performance-based design of buckling-restrained braced frames. The errors associated with the energy-balance concept were identified and were corrected by implementing proper correction factors. The design process began with the computation of the input energy from a response spectrum. Then the plastic energy computed based on the modified energy-balance concept was distributed to each story and the cross-sectional area of each brace was computed in such a way that all the plastic energy was dissipated by the brace. The proposed procedure was applied to the design of three-, six-, and eight-story steel frames with buckling-restrained braces for three different performance targets. According to the time-history analysis results, the mean values of the top story displacements of the model structures, designed in accordance with the proposed procedure, corresponded well with the given target displacements. Key words: energy-balance concept, buckling-restrained braces, hysteretic energy, performance-based seismic design.

Sign in / Sign up

Export Citation Format

Share Document