Evaluating the ductility characteristics of self-centering buckling-restrained shape memory alloy braces

Abou-Elfath, Hamdy

doi:10.1088/1361-665x/aa6abc

Cited by 30 publications

(12 citation statements)

References 13 publications

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“…On the other hand, when no failure is considered for the SMA braces, the strength of SMA‐braced frame after initial frame yielding remained almost constant for up to a roof drift of 0.045 and then increased due to post‐transformation hardening behavior of SMA braces. This type of pushover curves with post‐hardening characteristics have also been obtained in previous studies for the steel frames with SMA elements because the failure of the SMAs has not been considered . The results demonstrate that the strength and ductility of the frame without SMA brace failure consideration will be overestimated once the frame subjected to a severe earthquake.…”

Section: Influence Of Brace Failure Considerationsupporting

confidence: 80%

“…This type of pushover curves with post-hardening characteristics have also been obtained in previous studies for the steel frames with SMA elements because the failure of the SMAs has not been considered. 12,14,44 The results demonstrate that the strength and ductility of the frame without SMA brace failure consideration will be overestimated once the frame subjected to a severe earthquake.…”

Section: Pushover Analysismentioning

confidence: 93%

“…Among various applications of SMAs in seismic engineering, SMA‐based bracing systems have been one of the most commonly studied approach to enhance seismic performance of civil structures. Several researchers have numerically investigated the performance of SMA‐braced frames by assuming an SMA brace that consists of short SMA elements and connected to a rigid segment . There have been also several attempts to experimentally study the performance of SMA‐based devices and SMA braced steel frames.…”

Section: Introductionmentioning

confidence: 99%

“…Several researchers have numerically investigated the performance of SMA-braced frames by assuming an SMA brace that consists of short SMA elements and connected to a rigid segment. [11][12][13][14] There have been also several attempts to experimentally study the performance of SMA-based devices and SMA braced steel frames. Dolce et al 15 fabricated three different prestrained SMA wire-based devices and verified its feasibility through systematically experimental study under various conditions of deformation amplitude, loading frequency, and environmental temperature.…”

Section: Introductionmentioning

confidence: 99%

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Influence of shape memory alloy brace design parameters on seismic performance of self‐centering steel frame buildings

Shi

Ozbulut

Zhou

2019

Struct Control Health Monit

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Summary This paper investigates the seismic and collapse performance of shape memory alloy (SMA) braced steel frame structures considering the effects of various brace design parameters and ultimate state of SMAs. An SMA‐braced steel frame building is designed to have comparable strength and stiffness with a steel‐moment resisting frame selected as case study building. Then, the stiffness and ultimate deformation capacity of the SMA braces in the initially designed reference SMA‐braced frame are systematically varied. First, the static pushover analysis and incremental dynamic analysis are employed to illustrate the significance of SMA brace failure consideration in seismic performance assessment of steel frames with SMA elements. Then, the influence of SMA brace initial stiffness and ultimate deformation capacity on the seismic and collapse performance of SMA braced frames are studied through pushover analyses, nonlinear response history analyses, and incremental dynamic analysis. The results show that the SMA brace initial stiffness does not affect the interstory drift and floor absolute acceleration response at design and maximum considered earthquake level seismic hazard or collapse capacity of the frame. However, it has considerable influence on post‐event functionality of the frame. It is also found that the SMA brace ultimate deformation capacity should be at least 80% of maximum interstory drift demand at maximum considered earthquake level for satisfactory seismic performance, whereas larger values provide higher collapse capacity for the SMA‐braced frame.

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Section: Influence Of Brace Failure Considerationsupporting

confidence: 80%

Section: Pushover Analysismentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of shape memory alloy brace design parameters on seismic performance of self‐centering steel frame buildings

Shi

Ozbulut

Zhou

2019

Struct Control Health Monit

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“…From the study, the SC‐BRB was found to dissipate energy even with large self‐centering ratios based on limiting peak drifts proposed by the criteria. Abou‐Elfath used a strengthening technique by short‐segment superelastic SMA braces due to the lower elastic modulus of SMA in comparison with that of steel. The ductility characteristics of these newly proposed systems are investigated to assess their safety levels against the collapse of structure under earthquake loading.…”

Section: Introductionmentioning

confidence: 99%

Seismic performance of steel braced frames with self‐centering buckling‐restrained brace utilizing superelastic shape memory alloys

Nazarimofrad

Shokrgozar

2019

Structural Design Tall Build

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Buckling-restrained braced frame (BRB) is one of the newest seismic force-resisting systems used in buildings. However, one of the requirements for designing a structure is to provide a ductility behavior of structures to dissipate earthquake energy and to avoid residual drifts. These days, self-centering seismic lateral force-resisting systems have drawn attention due to their potentials to solve the above mentioned issues. On the other hand, shape memory alloys (SMAs) are characterized by unique superelastic behavior, which enables the material to recover its original shape after experiencing large deformations. The goal of this study is to assess BRBs whose ductility are improved by utilizing SMA. Nonlinear time history and incremental dynamic analysis techniques are applied to investigate the behavior of the two frames with different stories (four and eight stories) under different ground motion records. The results showed that utilizing BRB made of hybrid steel and SMA resulted in increasing ductility of the structure and decreasing residual displacements of the structures. KEYWORDS brace, ductility, dynamic pushover, nonlinear time history, self-centering, SMA | INTRODUCTIONThere are a plenty of seismic resistant members that have been developed to reduce the likelihood of collapse of structures subjected to earthquake such as braces, [1][2][3][4][5] shear wall, [6,7] confined reinforced concrete structures, [8] filled with high-performance concrete, [9] concrete-filled-steel tube structures, [10] and so on. These days, buckling-restrained braced frames (BRBs) have increasingly been employed as seismic load-resisting systems in the area with high seismic hazard due to the fact that their performance is much better than that of conventional braced frames.Despite the fact that the global geometric configuration of a BRB is very similar to a conventional braced frame, however, the members and behavior of BRB is clearly different from those of conventional braced frames. The key difference is that BRB systems do not buckle. [5,[11][12][13] Conventional braced frames have shown a poor performance in several recent ground motions because of limited ductility, insufficient energy dissipation capacity, and large residual deformations. [14] It is affirmed that BRBs made of steel efficiently resulted in providing structures with significant ductility, stable hysteretic behavior, and large energy dissipation capacity. [15] However, past studies have shown that steel BRBs commonly are brittle and undergo a large residual deformation after earthquakes. [16] The appearance of large residual deformations caused by strong earthquakes makes the residents of building insecure and may even demolish the building. On the other hand, repairing the residual deformations can be expensive and even impossible. [17] In recent years, researchers have attempted to utilize self-centering BRB systems containing SMA material to improve its ductility characteristics and decreasing residual deformations in structures. [18][19][20][21][22][2...

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Seismic robustness of self‐centering braced frames suffering tendon failure

Ping

Fang

Chen

et al. 2021

Earthq Engng Struct Dyn

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This paper comprehensively discusses the behavior and failure risk of self‐centering braced frames suffering tendon fracture. The fundamental mechanism of tendon failure in self‐centering braces (SCBs) is first introduced, followed by the design and analysis of a series of prototype buildings with different tendon materials and brace configurations. Assuming a normal distribution of tendon fracture strain, the dynamic behavior of the frames is then assessed by a suite of ground motion records, covering both far‐field and near‐fault ones. The collapse and residual deformation fragilities of the frames are further evaluated, and the study ends with a risk assessment considering a 50‐year service period. Among other findings, the study indicates that tendon fracture tends to increase the peak interstory drift, especially for the structure with smaller tendon fracture strains. Tendon fracture also compromises the self‐centering capability significantly, although there is no obvious statistical correlation between tendon fracture and the peak floor acceleration. The probability of collapse and that of exceedance of certain residual drift both increase evidently when tendon fracture is considered. The failure probabilities are closely related to the available deformability of the SCBs, where dual‐core SCBs show less sensitivity to tendon fracture. The probability of collapse of the considered frames over 50 years of service increases from 1.25‐2.12% to 3.58‐6.52% when tendon fracture is considered. Considering a residual drift threshold of 0.5%, the probability of exceedance of the same structures over the same life span increases from 1.78‐3.54% to 5.46‐9.71%.

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Evaluating the ductility characteristics of self-centering buckling-restrained shape memory alloy braces

Cited by 30 publications

References 13 publications

Influence of shape memory alloy brace design parameters on seismic performance of self‐centering steel frame buildings

Influence of shape memory alloy brace design parameters on seismic performance of self‐centering steel frame buildings

Seismic performance of steel braced frames with self‐centering buckling‐restrained brace utilizing superelastic shape memory alloys

Seismic robustness of self‐centering braced frames suffering tendon failure

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