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) 2067–2074

SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Performance of RC Beams with NSM Fe-SMA after Eight-Year Exposure and Sustained Loading SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Performance of RC Beams with NSM Fe-SMA after Eight-Year Exposure and Sustained Loading

Yunus Harmanci a* , Christoph Czaderski a , Moslem Shahverdi a,b a Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, 8600, Switzerland b School of Civil Engineering, University of Tehran, Tehran 4563-11155, Iran Yunus Harmanci a* , Christoph Czaderski a , Moslem Shahverdi a,b a Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, 8600, Switzerland b School of Civil Engineering, University of Tehran, Tehran 4563-11155, Iran

Abstract Low-cost iron-based shape memory alloys (Fe-SMAs) have emerged as a viable alternative to carbon fiber reinforced polymers (CFRP) for near-surface mounted strengthening of reinforced concrete (RC) structures, particularly due to their ease of prestressing and their plastic behavior similar to reinforcing steel. The short-term behavior has already been investigated in detail, yet the durability of such systems still remain a relatively unexplored area, as there is a scarcity of long-term experimental studies available. To address this gap, two RC beams strengthened with NSM Fe-SMA were subjected to natural environmental conditions for an extended period of 8 years, during which they were subjected to sustained loading beyond their cracking load level. Subsequently, the beams were subjected to four-point bending loading until failure. Results were compared with a previous short-term study involving identical specimens that had not been exposed to environmental factors or sustained loading. A comprehensive cross section analysis (CSA) further complements the experimental results, which effectively captured both the long-term and bending behavior. Influence of concrete creep and shrinkage, as well as Fe-SMA relaxation is discussed by employing the CSA. Lastly, influential parameters and their impact on structural performance were identified via sensitivity analysis. © 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: Iron-based shape memory alloy; Near-surface mounted strengthening; Prestressing; Durability; Sustained loading Abstract Low-cost iron-based shape memory alloys (Fe-SMAs) have emerged as a viable alternative to carbon fiber reinforced polymers (CFRP) for near-surface mounted strengthening of reinforced concrete (RC) structures, particularly due to their ease of prestressing and their plastic behavior similar to reinforcing steel. The short-term behavior has already been investigated in detail, yet the durability of such systems still remain a relatively unexplored area, as there is a scarcity of long-term experimental studies available. To address this gap, two RC beams strengthened with NSM Fe-SMA were subjected to natural environmental conditions for an extended period of 8 years, during which they were subjected to sustained loading beyond their cracking load level. Subsequently, the beams were subjected to four-point bending loading until failure. Results were compared with a previous short-term study involving identical specimens that had not been exposed to environmental factors or sustained loading. A comprehensive cross section analysis (CSA) further complements the experimental results, which effectively captured both the long-term and bending behavior. Influence of concrete creep and shrinkage, as well as Fe-SMA relaxation is discussed by employing the CSA. Lastly, influential parameters and their impact on structural performance were identified via sensitivity analysis. © 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: Iron-based shape memory alloy; Near-surface mounted strengthening; Prestressing; Durability; Sustained loading © 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.: +41-58-765-6155. E-mail address: yunus.harmanci@empa.ch * Corresponding author. Tel.: +41-58-765-6155. E-mail address: yunus.harmanci@empa.ch

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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