PSI - Issue 64

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ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000 Structural Integrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 64 (2024) 2028–2035

SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Self-centering capacity of RC columns reinforced by martensitic NiTi SMA bars in plastic hinge region SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Self-centering capacity of RC columns reinforced by martensitic NiTi SMA bars in plastic hinge region

E. Choi a , SJ. Park a, *, BT. Nhan a , JS. Byun a , SJ. Lee, a,b , YS. Lee a,c a Department of Civil and Environmental Engineering, Hongik University, Seoul 04066, Republic of Korea E. Choi a , SJ. Park a, *, BT. Nhan a , JS. Byun a , SJ. Lee, a,b , YS. Lee a,c a Department of Civil and Environmental Engineering, Hongik University, Seoul 04066, Republic of Korea b FITI Testing & Research Institute, Seoul 07791, Republic of Korea c FITI Testing & Research Institute, Cheongju 07791, Republic of Korea b FITI Testing & Research Institute, Seoul 07791, Republic of Korea c FITI Testing & Research Institute, Cheongju 07791, Republic of Korea

Abstract This study aimed to assess self-centering in reinforced concrete (RC) columns incorporating martensitic shape memory alloy (SMA) bars within the plastic hinge region. Three RC columns were prepared: one conventional, the others with SMA bars in the hinge zone. Columns, 400 mm in diameter and 1400 mm in height, with an aspect ratio of 3.5, were used. SMA bars, 400 mm long, were connected to steel rebars with specialized couplers. Through cyclic lateral loading, lateral displacements and corresponding forces were measured. Strain in the SMA bars was also recorded. The RC column with SMA bars displayed a plastic hinge near the couplers, concentrating concrete damage at this location, a departure from the conventional column failure mode. SMA bars remained elastic, while steel rebars yielded within the couplers. The RC column with SMA bars demonstrated exceptional self centering, recovering about 95% at a 5% drift. However, its energy dissipation capacity was lower than the conventional RC column. The equivalent damping ratio for the RC column with SMA bars stabilized at approximately 3% after a 1.75% drift. This suggests that the remarkable self-centering capacity in the RC column with SMA bars was primarily due to the elastic behavior of the martensitic SMA bars. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers Keywords: Self-centering capacity; plastic hinge; RC column; martensitic SMA bars; pushover behavior; Abstract This study aimed to assess self-centering in reinforced concrete (RC) columns incorporating martensitic shape memory alloy (SMA) bars within the plastic hinge region. Three RC columns were prepared: one conventional, the others with SMA bars in the hinge zone. Columns, 400 mm in diameter and 1400 mm in height, with an aspect ratio of 3.5, were used. SMA bars, 400 mm long, were connected to steel rebars with specialized couplers. Through cyclic lateral loading, lateral displacements and corresponding forces were measured. Strain in the SMA bars was also recorded. The RC column with SMA bars displayed a plastic hinge near the couplers, concentrating concrete damage at this location, a departure from the conventional column failure mode. SMA bars remained elastic, while steel rebars yielded within the couplers. The RC column with SMA bars demonstrated exceptional self centering, recovering about 95% at a 5% drift. However, its energy dissipation capacity was lower than the conventional RC column. The equivalent damping ratio for the RC column with SMA bars stabilized at approximately 3% after a 1.75% drift. This suggests that the remarkable self-centering capacity in the RC column with SMA bars was primarily due to the elastic behavior of the martensitic SMA bars. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers Keywords: Self-centering capacity; plastic hinge; RC column; martensitic SMA bars; pushover behavior; © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers

* Corresponding author. Tel.: +85-2-320-3060; fax: +82-0-332-1244. E-mail address: eunsoochoi@hongik.ac.kr * Corresponding author. Tel.: +85-2-320-3060; fax: +82-0-332-1244. E-mail address: eunsoochoi@hongik.ac.kr

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers

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