Rocking bridge piers equipped with shape memory alloy (SMA) washer springs

Fang, Cheng; Liang, Dong; Zheng, Yue; Yam, Michael C.H.; Sun, Ruiqin

doi:10.1016/j.engstruct.2020.110651

Cited by 78 publications

(33 citation statements)

References 49 publications

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“…SMA elements with larger load resistance, for example, SMA cables, may be more feasible for isolation bearings. 26,53 While there has been encouraging progress on SMA-based isolation bearings, most of the existing studies focused on numerical analysis, whereas test evidence, especially full-scale tests, is very limited. Practical issues such as effective gripping and installation details cannot be fully reflected by the numerical studies.…”

Section: Introductionmentioning

confidence: 99%

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

Fang

Liang

Zheng

et al. 2021

Earthq Engng Struct Dyn

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This study presents a novel type of shape memory alloy (SMA) cable-restrained high damping rubber (SMA-HDR) bearing, which is particularly suited to nearfault (NF) regions where the pulsing effect potentially exists in the ground motions. The working mechanism of the bearing is first described, followed by an experimental investigation on a full-scale SMA-HDR bearing specimen. The test results confirm the efficient restraining effect offered by the SMA cables, which contribute to 65% and 24.4% of the lateral load resistance and total energy dissipation, respectively, prior to the initial fracture of the SMA cables. The failure of the cables is initiated near the end grip where moderate stress concentration exists at this region. Following the experimental study, the numerical modeling strategy for the bearing is discussed, and a case study is then presented, demonstrating the application of the SMA-HDR bearings in the Datianba #2 highway bridge, a real project that first adopts the proposed bearings in the world. A simplified design process is introduced for the bridge with novel SMA-HDR bearings to mitigate the potential damage during strong earthquakes especially the NF ones. The system-level analysis on the prototype bridge shows that the novel SMA-HDR bearings equipped with ten 7×7×1.2 SMA cables in each bearing could reduce the average maximum bearing displacement (MBD) by nearly 30% compared with the conventional bridge with HDR bearings. The application of the novel SMA-HDR bearing can significantly alleviate the pounding effect, especially under the NF earthquakes. The presence of the SMA cables tends to increase the maximum force response of the piers, but this effect is minor and under control.

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Section: Introductionmentioning

confidence: 99%

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

Fang

Liang

Zheng

et al. 2021

Earthq Engng Struct Dyn

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“…In particular, a more unique system-level behavior is anticipated when the Fe-SMA elements are employed because of the special cyclic hardening and unloading spring-back behavior. Fe-SMA may also be used together with super-elastic Nitinol to reach a hybrid design which enables a good balance among self-centering capability, energy dissipation, and cost, compared with a pure Nitinol solution [ 44 , 163 , 164 , 165 , 166 , 167 ]. Preliminary seismic collapse safety assessment has revealed that the collapse capacity of beam-column joints equipped with Fe-SMA is significantly improved [ 168 ].…”

Section: Further Research Needsmentioning

confidence: 99%

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

Zhang

et al. 2022

Materials

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As a promising candidate in the construction industry, iron-based shape memory alloy (Fe-SMA) has attracted lots of attention in the engineering and metallography communities because of its foreseeable benefits including corrosion resistance, shape recovery capability, excellent plastic deformability, and outstanding fatigue resistance. Pilot applications have proved the feasibility of Fe-SMA as a highly efficient functional material in the construction sector. This paper provides a review of recent developments in research and design practice related to Fe-SMA. The basic mechanical properties are presented and compared with conventional structural steel, and some necessary explanations are given on the metallographic transformation mechanism. Newly emerged applications, such as Fe-SMA-based prestressing/strengthening techniques and seismic-resistant components/devices, are discussed. It is believed that Fe-SMA offers a wide range of applications in the construction industry but there still remains problems to be addressed and areas to be further explored. Some research needs at material-level, component-level, and system-level are highlighted in this paper. With the systematic information provided, this paper not only benefits professionals and researchers who have been working in this area for a long time and wanting to gain an in-depth understanding of the state-of-the-art, but also helps enlighten a wider audience intending to get acquainted with this exciting topic.

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“…A total of 6 strain gauges were mounted on the longitudinal rebars at the plastic hinge region, as shown in Figure 6(b). Other details can be found elsewhere (Fang et al, 2020).…”

Section: Tests Conducted By the Authors And Colleagues (Fang Et Almentioning

confidence: 99%

An innovative seismic-resilient bridge with shape memory alloy-washer-based footing rocking RC piers

Zheng

Fang

Liang

et al. 2020

Journal of Intelligent Material Systems and Structures

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This study proposes a new footing rocking pier which employs shape memory alloy (SMA) washers as its kernel elements. Apart from providing self-centering capability and energy dissipation, the SMA washers enable a “limited rocking” behavior for the pier, helping enhance the seismic resilience of the bridges. The study commences with quasi-static tests on SMA washer groups with various stack patterns. Subsequently, a 1/4 scale SMA-washer-based rocking pier specimen is tested. Following the experimental study, a bridge system adopting the SMA-washer-based rocking pier is carefully designed. An iterative seismic design approach is proposed for the rocking pier, followed by a system level analysis on the entire bridge system. A suite of ground motions corresponding to two intensity levels are considered. The performance of the innovative bridge is also compared with a conventional bridge with fixed-base piers. The results reveal that the new system exhibits superior performance to the conventional bridge in terms of pier damage control, which is achieved with acceptable sacrifice of other performance indices such as bearing displacement and peak drift ratio. A further parametric study suggests that the response of the bridge with the proposed pier is related to the load resistance and deformability of the SMA washers.

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Rocking bridge piers equipped with shape memory alloy (SMA) washer springs

Cited by 78 publications

References 49 publications

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

An innovative seismic-resilient bridge with shape memory alloy-washer-based footing rocking RC piers

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