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Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data
Dams are important structures whose safety in operation is critical owing to the socioeconomic impacts associated with their collapse. Alkali-Silica Reaction (ASR) is a deleterious chemical reaction that affects the performance and safety of numerous concrete dam structures around the world. To ensu...
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| Format: | Thesis |
| Language: | English English |
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Department of Civil Engineering
2025
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| _version_ | 1867613168178561024 |
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| access_status_str | Open Access |
| author | Nyoni, Bukhosi |
| author2 | Moyo, Pilate |
| author_browse | Moyo, Pilate Nyoni, Bukhosi |
| author_facet | Moyo, Pilate Nyoni, Bukhosi |
| author_sort | Nyoni, Bukhosi |
| collection | Thesis |
| description | Dams are important structures whose safety in operation is critical owing to the socioeconomic impacts associated with their collapse. Alkali-Silica Reaction (ASR) is a deleterious chemical reaction that affects the performance and safety of numerous concrete dam structures around the world. To ensure dam safety, a well-structured dam surveillance program that includes ambient vibration monitoring is essential as it enables an in-depth understanding of the behaviour of a dam in operation. Additionally, structural behaviour analysis through numerical models such as finite element (FE) models, is a crucial aspect of dam safety evaluations that allows dam safety engineers to predict the current and future behaviour of dams under various load combinations. The challenge in finite element analysis (FEA) is generating an FE model that is representative of the observed behaviour and condition of the dam to be trusted and used for further study. This study sort to find the best updating parameters and finite element model updating approach to achieve representative and reliable finite element models for the safety assessment of arch dams affected by ASR. This was achieved through sensitivity analysis of the behaviour (both dynamic behaviour and static behaviour) of concrete arch dams to (i) geometrical properties, (ii) material properties and (iii) load effects on the dam-foundation-reservoir system, to identify the best updating parameters. Following which a model updating procedure was proposed and implemented. It was observed that the behaviour of concrete arch dams is subject to their geometric properties. Their dynamic behaviour was observed to be largely sensitive to the dam- foundation-reservoir system stiffness and water level whereas their thermal behaviour was sensitive to the system thermal properties. Additionally, it was observed that the dynamic response is not as sensitive to ASR loading as initially assumed. Based on these findings, the proposed finite element model updating procedure begins with the updating of the system stiffness using modal parameters, followed by the updating of the thermal properties, and then updating of the parameters critical to ASR modelling. The proposed multi-step model updating procedure was successfully implemented to update a finite element model for a case study double curvature arch dam affected by ASR achieving agreeable results between the measured and predicted behaviour observations. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/41895 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:31:50.330Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Department of Civil Engineering |
| publisherStr | Department of Civil Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/41895 Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data Nyoni, Bukhosi Moyo, Pilate Finite element model updating Arch dam Ambient vibration monitoring Performance assessment Alkali-silica reaction Dams are important structures whose safety in operation is critical owing to the socioeconomic impacts associated with their collapse. Alkali-Silica Reaction (ASR) is a deleterious chemical reaction that affects the performance and safety of numerous concrete dam structures around the world. To ensure dam safety, a well-structured dam surveillance program that includes ambient vibration monitoring is essential as it enables an in-depth understanding of the behaviour of a dam in operation. Additionally, structural behaviour analysis through numerical models such as finite element (FE) models, is a crucial aspect of dam safety evaluations that allows dam safety engineers to predict the current and future behaviour of dams under various load combinations. The challenge in finite element analysis (FEA) is generating an FE model that is representative of the observed behaviour and condition of the dam to be trusted and used for further study. This study sort to find the best updating parameters and finite element model updating approach to achieve representative and reliable finite element models for the safety assessment of arch dams affected by ASR. This was achieved through sensitivity analysis of the behaviour (both dynamic behaviour and static behaviour) of concrete arch dams to (i) geometrical properties, (ii) material properties and (iii) load effects on the dam-foundation-reservoir system, to identify the best updating parameters. Following which a model updating procedure was proposed and implemented. It was observed that the behaviour of concrete arch dams is subject to their geometric properties. Their dynamic behaviour was observed to be largely sensitive to the dam- foundation-reservoir system stiffness and water level whereas their thermal behaviour was sensitive to the system thermal properties. Additionally, it was observed that the dynamic response is not as sensitive to ASR loading as initially assumed. Based on these findings, the proposed finite element model updating procedure begins with the updating of the system stiffness using modal parameters, followed by the updating of the thermal properties, and then updating of the parameters critical to ASR modelling. The proposed multi-step model updating procedure was successfully implemented to update a finite element model for a case study double curvature arch dam affected by ASR achieving agreeable results between the measured and predicted behaviour observations. 2025-09-19T12:32:01Z 2025-09-19T12:32:01Z 2025 2025-09-19T07:29:44Z Thesis / Dissertation Doctoral PhD http://hdl.handle.net/11427/41895 en eng application/pdf Department of Civil Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Finite element model updating Arch dam Ambient vibration monitoring Performance assessment Alkali-silica reaction Nyoni, Bukhosi Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| thesis_degree_str | Doctoral |
| title | Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| title_full | Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| title_fullStr | Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| title_full_unstemmed | Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| title_short | Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data |
| title_sort | finite element model updating of concrete arch dams affected by alkali silica reaction using ambient vibration monitoring and dam surveillance data |
| topic | Finite element model updating Arch dam Ambient vibration monitoring Performance assessment Alkali-silica reaction |
| url | http://hdl.handle.net/11427/41895 |
| work_keys_str_mv | AT nyonibukhosi finiteelementmodelupdatingofconcretearchdamsaffectedbyalkalisilicareactionusingambientvibrationmonitoringanddamsurveillancedata |