Effectiveness of superelastic bars for seismic rehabilitation of clay‐unit masonry walls

Shrestha, Kshitij C.; Araki, Yoshikazu; Nagae, T.; Omori, Toshihiro; Sutou, Yuji; Kainuma, Ryosuke; Ishida, K.

doi:10.1002/eqe.2241

Cited by 16 publications

(8 citation statements)

References 35 publications

(43 reference statements)

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“…Moreover, SMAs have excellent corrosion resistance and good low-cycle fatigue life [8,9]. A variety of seismic-resisting self-centering devices or structural members have been developed based on these favorable features of superelastic SMAs [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], including SMA base isolators for elevated highway bridges and frames [11,21], SMA dampers [12], SMA restrainers for bridge retrofitting [14], SMA bars in precast segmental bridge piers [23], etc.…”

Section: Introductionmentioning

confidence: 99%

Shake table test and numerical study of self‐centering steel frame with SMA braces

Qiu

Zhu

2016

Earthq Engng Struct Dyn

274

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Summary Given their excellent self‐centering and energy‐dissipating capabilities, superelastic shape memory alloys (SMAs) become an emerging structural material in the field of earthquake engineering. This paper presents experimental and numerical studies on a scaled self‐centering steel frame with novel SMA braces (SMAB), which utilize superelastic Ni–Ti wires. The braces were fabricated and cyclically characterized before their installation in a two‐story one‐bay steel frame. The equivalent viscous damping ratio and ‘post‐yield’ stiffness ratio of the tested braces are around 5% and 0.15, respectively. In particular, the frame was seismically designed with nearly all pin connections, including the pinned column bases. To assess the seismic performance of the SMA braced frame (SMABF), a series of shake table tests were conducted, in which the SMABF was subjected to ground motions with incremental seismic intensity levels. No repair or replacement of structural members was performed during the entire series of tests. Experimental results showed that the SMAB could withstand several strong earthquakes with very limited capacity degradation. Thanks to the self‐centering capacity and pin‐connection design, the steel frame was subjected to limited damage and zero residual deformation even if the peak interstory drift ratio exceeded 2%. Good agreement was found between the experimental results and numerical simulations. The current study validates the prospect of using SMAB as a standalone seismic‐resisting component in critical building structures when high seismic performance or earthquake resilience is desirable under moderate and strong earthquakes. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Shake table test and numerical study of self‐centering steel frame with SMA braces

Qiu

Zhu

2016

Earthq Engng Struct Dyn

274

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“…The strain rate was selected to be slow enough to realize isothermal condition. In the second set of cyclic tension tests, on the other hand, the number and amplitude of loading cycles were determined to reflect the conditions used in seismic design of buildings and bridges (Shrestha et al 2013;Hosseini et al 2015;Araki et al 2016 ; Chang and Araki 2016; Varela and Saiidi 2017). The strain rate was determined to be as fast as possible within the capacity of the loading machine.…”

Section: Test Methodsmentioning

confidence: 99%

“…To resolve the issues inherent in superelastic Ni-Ti SMAs-e.g., low cold workability (or brittleness), low machinability, and high material cost-superelastic Cu-Al-Mn SMA rods have been developed (Kainuma et al 1996(Kainuma et al , 1998Sutou et al 2002Sutou et al , 2005Sutou et al , 2013Omori et al 2013;Kusama et al 2017). Studies have also been done on how the material can be used for improving the response of civil structures, like buildings and bridges, against earthquakes (Shrestha et al 2013;Hosseini et al 2015;Araki et al 2016;Varela and Saiidi 2017). Superelasticity is enhanced in a bamboo or columnar grained structure 1 Manager, Technology Development Dept., Special Metals Div., Furukawa Techno Material Co. Ltd., 5-1-8, Higashi-Yawata, Hiratsuka 2540016, Japan (corresponding author) (Kainuma et al 1998;Sutou et al 2002;Liu et al 2015), but the best superelasticity can be obtained in a single crystal in Cu-Al-Mn SMAs (Omori et al 2020;Kise et al 2021), which can be produced with cyclic heat treatment (Omori et al 2013;Kusama et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Roll-Threading Superelastic Cu-Al-Mn SMA Rods

Kise

Kataoka

Takamatsu

et al. 2021

J. Mater. Civ. Eng.

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This paper examines the feasibility of roll-threading superelastic Cu-Al-Mn shape memory allow (SMA) rods. The key idea behind this study was to perform roll-threading between quenching and aging, where cold workability of the material is relatively high. To obtain excellent superelasticity, single-crystal superelastic Cu-Al-Mn SMA rods were prepared with 16-mm diameter and 300-mm length. Threadability was studied by dimensional inspection and surface observations. Mechanical properties of the threaded rods were examined by cyclic tension tests. Comparisons between rolled and cut threads were made by cutting each single-crystal rod into halves to obtain two rod specimens having the same crystal orientation, thus ensuring fair comparison by excluding the influence of variations in orientations of the single-crystal rod. From the study, it was demonstrated that roll-threading of Cu-Al-Mn SMA rods was possible if roll-threading is performed between quenching and aging. Since additional heat treatment from the ordinary manufacturing process is unnecessary, roll-threading of Cu-Al-Mn SMA rods is as easy as that of steel rods. It was also demonstrated that the roll threads had significantly superior fatigue resistance compared with the cut threads of the same size. These results suggest that superelastic Cu-Al-Mn SMA rods with rolled threads are suitable for mass production to be used in structural and earthquake engineering applications.

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“…As such, the favorable features of superelastic SMAs attract increasing attention in the community of earthquake engineering. A variety of seismic‐resisting devices and structural components were developed during the last decades . Typical applications include dampers, isolators for buildings, restrainers for bridges, high‐performance bars, bolts and springs, and self‐centering braces …”

Section: Introductionmentioning

confidence: 99%

Effect of hysteretic properties of SMAs on seismic behavior of self-centering concentrically braced frames

Hou

Qiu

et al. 2017

Struct Control Health Monit

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Summary Shape memory alloys (SMAs) exhibit nearly ideal superelastic properties when the ambient temperature is above the austenite finish temperature, which enables them to recover deformation and dissipate energy for the seismic‐resisting structures. This unique hysteretic properties of SMAs indicate they are very promising in developing self‐centering structures. As such, recent studies installed SMAs in concentrically braced frames (CBFs) to form SMA‐based self‐centering CBFs (SCCBFs) and illustrated that the structures performed excellently with controlled peak drift and eliminated residual drift upon earthquakes. SMAs show variability in the hysteretic parameters due to the difference in metal types, crystallographic structure, component ratios, and heating treatments in producing process. Thus, this necessitates an investigation into the associated effect on the seismic performance of SMA‐based SCCBFs. To this end, this study selects 3 SMAs, proposes a bracing form, and installs SMA braces in the CBFs. Prior to the seismic analysis, all 3 frames are designed by an ad hoc design method. The focus of this paper is to understand the effect of hysteretic properties on the seismic behavior of SMA‐based SCCBFs. Intensive nonlinear time history analyses are carried out to assess the seismic performance of these structures under frequently occurred earthquakes and design basis earthquakes. The analytical results indicate the properly designed SCCBFs are able to meet prescribed performance targets and display comparable seismic demands, irrespective of the SMA types. This study suggests that using SMAs with greater hysteretic parameters is more favorable, from the perspective of saving material consumption and controlling acceleration demands.

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Effectiveness of superelastic bars for seismic rehabilitation of clay‐unit masonry walls

Cited by 16 publications

References 35 publications

Shake table test and numerical study of self‐centering steel frame with SMA braces

Shake table test and numerical study of self‐centering steel frame with SMA braces

Feasibility of Roll-Threading Superelastic Cu-Al-Mn SMA Rods

Effect of hysteretic properties of SMAs on seismic behavior of self-centering concentrically braced frames

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