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A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete
Dissertation (MEng)--University of Pretoria, 2019.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2020
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| _version_ | 1867613731726295040 |
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| access_status_str | Open Access |
| author2 | Kok, Schalk |
| author_browse | Kok, Schalk |
| author_facet | Kok, Schalk |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/75657 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:48.647Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/75657 A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete Kok, Schalk tamsinschoenst@gmail.com Wilke, Daniel Nicolas Bam, T.J. Fibre reinforced concrete Steel hooked-end fibres Pull-out test simulation Wire drawing simulation Inverse problem UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Dissertation (MEng)--University of Pretoria, 2019. The classical test to confirm the performance of a given fibre design for use in reinforced concrete is the pull-out test. While attempts have been made to simulate the performance of such pull-out tests, in practice it has been found that there is a significant disparity between prediction and real-life performance. The high strength of steel reinforcing fibres is a consequence of the cold wire drawing process and subsequent fabrication. Residual stresses exist in cold drawn wire as a consequence of the elastic response to a non-uniform distribution of plastic strain. This also introduces a yield strength profile where yield strength varies radially through the wire. The question arises as to whether fibre design should use a starting material model that considers these properties. This thesis examines whether the tensile test, simple bend test and pull-out test provide enough information to define a starting material model that may be used for further design and simulation of such fibres. Since the details of the wire drawing process and material specification are proprietary and therefore unknown, a sensitivity study was conducted to determine which aspects of the wire drawing process have the greatest effect on the pull-out curve and the following were established as being significant: • Plastic strain due to wire drawing was shown to be the most important factor. • The bilinear curve was shown to be a suitable approximation for the stress-strain curve. • Replacing the plastic strain profile with a single value of average equivalent plastic strain is practical. The following were established as having negligible effect: • The consequences of the hooked-end forming process. • The residual stress profiles due to wire drawing provided that the above was also excluded. • The hardening law While inverse analysis demonstrated that all tests provide sufficient information to determine the required properties for this bilinear material model, the pull-out test was shown to provide more accurate approximations of the maximum pull-out force at the first and second peaks and the bend test was shown to produce more accurate approximations of the energy associated with pull-out. Good correlation with the baseline pull-out curve was found for both the isotropic and the kinematic hardening laws and it is concluded that behaviour during pull-out is insensitive to the hardening law. Sensitivity analysis and characterisation of the material model using an experimental pull-out curve demonstrated the importance of the coefficient of friction. Full characterisation using the pull-out curve therefore requires the solution to a three-variable problem: yield strength, tangent modulus and coefficient of friction. This was a suggested topic for further study. mi2025 Mechanical and Aeronautical Engineering MEng (Mech) Unrestricted SDG-09: Industry, innovation and infrastructure SDG-11: Sustainable cities and communities 2020-08-12T11:26:03Z 2020-08-12T11:26:03Z 2020 2019 Dissertation Bam, T 2019, A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete, MEng (Mech) Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/75657> S2020 http://hdl.handle.net/2263/75657 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Fibre reinforced concrete Steel hooked-end fibres Pull-out test simulation Wire drawing simulation Inverse problem UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title | A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title_full | A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title_fullStr | A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title_full_unstemmed | A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title_short | A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete |
| title_sort | computer based justification for using the simple bend test as the basis for predicting the performance of steel hooked end fibres in reinforced concrete |
| topic | Fibre reinforced concrete Steel hooked-end fibres Pull-out test simulation Wire drawing simulation Inverse problem UCTD Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities |
| url | http://hdl.handle.net/2263/75657 |