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Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection
Distributed fiber-optic sensing (DFOS) technologies have been used for decades to detect damage in infrastructure. One recent DFOS technology, Optical Frequency Domain Reflectometry (OFDR), has attracted attention from the structural engineering community because its high spatial resolution and refi...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9148171/ https://www.ncbi.nlm.nih.gov/pubmed/35632369 http://dx.doi.org/10.3390/s22103957 |
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author | Zhang, Shenghan Liu, Han Darwish, Esam Mosalam, Khalid M. DeJong, Matthew J. |
author_facet | Zhang, Shenghan Liu, Han Darwish, Esam Mosalam, Khalid M. DeJong, Matthew J. |
author_sort | Zhang, Shenghan |
collection | PubMed |
description | Distributed fiber-optic sensing (DFOS) technologies have been used for decades to detect damage in infrastructure. One recent DFOS technology, Optical Frequency Domain Reflectometry (OFDR), has attracted attention from the structural engineering community because its high spatial resolution and refined accuracy could enable new monitoring possibilities and new insight regarding the behavior of reinforced concrete (RC) structures. The current research project explores the ability and potential of OFDR to measure distributed strain in RC structures through laboratory tests on an innovative beam–column connection, in which a partial slot joint was introduced between the beam and the column to control damage. In the test specimen, fiber-optic cables were embedded in both the steel reinforcement and concrete. The specimen was tested under quasi-static cyclic loading with increasing displacement demand at the structural laboratory of the Pacific Earthquake Engineering Research (PEER) Center of UC Berkeley. Different types of fiber-optic cables were embedded both in the concrete and the rebar. The influence of the cable coating and cable position are discussed. The DFOS results are compared with traditional measurements (DIC and LVDT). The high resolution of DFOS at small deformations provides new insights regarding the mechanical behavior of the slotted RC beam–column connection, including direct measurement of beam curvature, rebar deformation, and slot opening and closing. A major contribution of this work is the quantification of the performance and limitations of the DFOS system under large cyclic strains. Performance is quantified in terms of non-valid points (which occur in large strains when the DFOS analyzer does not return a strain value), maximum strain that can be reliably measured, crack width that causes cable rupture, and the effect of the cable coating on the measurements. Structural damage indices are also proposed based on the DFOS results. These damage indices correlate reasonably well with the maximum sustained drift, indicating the potential of using DFOS for RC structural damage assessment. The experimental data set is made publicly available. |
format | Online Article Text |
id | pubmed-9148171 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-91481712022-05-29 Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection Zhang, Shenghan Liu, Han Darwish, Esam Mosalam, Khalid M. DeJong, Matthew J. Sensors (Basel) Article Distributed fiber-optic sensing (DFOS) technologies have been used for decades to detect damage in infrastructure. One recent DFOS technology, Optical Frequency Domain Reflectometry (OFDR), has attracted attention from the structural engineering community because its high spatial resolution and refined accuracy could enable new monitoring possibilities and new insight regarding the behavior of reinforced concrete (RC) structures. The current research project explores the ability and potential of OFDR to measure distributed strain in RC structures through laboratory tests on an innovative beam–column connection, in which a partial slot joint was introduced between the beam and the column to control damage. In the test specimen, fiber-optic cables were embedded in both the steel reinforcement and concrete. The specimen was tested under quasi-static cyclic loading with increasing displacement demand at the structural laboratory of the Pacific Earthquake Engineering Research (PEER) Center of UC Berkeley. Different types of fiber-optic cables were embedded both in the concrete and the rebar. The influence of the cable coating and cable position are discussed. The DFOS results are compared with traditional measurements (DIC and LVDT). The high resolution of DFOS at small deformations provides new insights regarding the mechanical behavior of the slotted RC beam–column connection, including direct measurement of beam curvature, rebar deformation, and slot opening and closing. A major contribution of this work is the quantification of the performance and limitations of the DFOS system under large cyclic strains. Performance is quantified in terms of non-valid points (which occur in large strains when the DFOS analyzer does not return a strain value), maximum strain that can be reliably measured, crack width that causes cable rupture, and the effect of the cable coating on the measurements. Structural damage indices are also proposed based on the DFOS results. These damage indices correlate reasonably well with the maximum sustained drift, indicating the potential of using DFOS for RC structural damage assessment. The experimental data set is made publicly available. MDPI 2022-05-23 /pmc/articles/PMC9148171/ /pubmed/35632369 http://dx.doi.org/10.3390/s22103957 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Zhang, Shenghan Liu, Han Darwish, Esam Mosalam, Khalid M. DeJong, Matthew J. Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title | Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title_full | Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title_fullStr | Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title_full_unstemmed | Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title_short | Distributed Fiber-Optic Strain Sensing of an Innovative Reinforced Concrete Beam–Column Connection |
title_sort | distributed fiber-optic strain sensing of an innovative reinforced concrete beam–column connection |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9148171/ https://www.ncbi.nlm.nih.gov/pubmed/35632369 http://dx.doi.org/10.3390/s22103957 |
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