Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design
Cross laminated timber (CLT), with its typical orthogonal layering and exposure to out-of-plane bending, develops inherent rolling shear stresses. These stresses need to be checked during the ultimate limit state design process. With the ongoing revision of Eurocode 5, a discussion regarding the cha...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Buildings |
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| Online Access: | https://www.mdpi.com/2075-5309/13/11/2831 |
| _version_ | 1797459927566909440 |
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| author | David Glasner Andreas Ringhofer Reinhard Brandner Gerhard Schickhofer |
| author_facet | David Glasner Andreas Ringhofer Reinhard Brandner Gerhard Schickhofer |
| author_sort | David Glasner |
| collection | DOAJ |
| description | Cross laminated timber (CLT), with its typical orthogonal layering and exposure to out-of-plane bending, develops inherent rolling shear stresses. These stresses need to be checked during the ultimate limit state design process. With the ongoing revision of Eurocode 5, a discussion regarding the characteristic value of the rolling shear strength of CLT has arisen. One obstacle in the discussion is seen in the lack of harmonized regulations concerning how to determine rolling shear properties. This circumstance manifests in the greatly diverging test results of different institutions testing the rolling shear strength. The paper at hand aims to propose a candidate for such harmonized regulations. To achieve this, the most common test setups, such as the inclined shear test, three- and four-point bending tests, etc., were numerically and experimentally investigated. Within the numerical investigations, a comparison of the most common calculation methods (Timoshenko beam theory, modified γ-method, Shear Analogy Method, and Finite Element Analysis) for evaluating rolling shear stresses was included. In the experimental program, parameters such as the specimen width, number, and thickness of the cross layer(s), shear length, optional reinforcement against the stresses perpendicular to the grain, and the overall test setup were varied. It was found that the used test setups themselves and the area of the cross layer(s) (shear length, number, and thickness of the cross layer(s)) have a major impact on the rolling shear strength. In contrast, no effect was found from the calculation methods. Based on these findings and on a database of approx. 300 four-point bending rolling shear tests on CLT specimens from five well-established CLT manufacturers, a model for the regulation of the rolling shear strength of CLT is proposed, in combination with a corresponding four-point bending test setup. Afterwards, with two additionally conducted four-point bending test series, the proposed model is successfully validated. The conclusions and recommendations in respect to the test setup (four-point bending), evaluation procedure (Timoshenko beam theory), reference characteristic rolling shear strength, and the model, which allows adapting the reference rolling shear strength to individual conditions, are seen as a worthy basis for a more objective discussion on this topic. |
| first_indexed | 2024-03-09T16:57:55Z |
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| institution | Directory Open Access Journal |
| issn | 2075-5309 |
| language | English |
| last_indexed | 2024-03-09T16:57:55Z |
| publishDate | 2023-11-01 |
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| series | Buildings |
| spelling | doaj.art-adabd99f3bb1475284692e4f91f944ab2023-11-24T14:33:35ZengMDPI AGBuildings2075-53092023-11-011311283110.3390/buildings13112831Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and DesignDavid Glasner0Andreas Ringhofer1Reinhard Brandner2Gerhard Schickhofer3Institute of Timber Engineering and Wood Technology, Graz University of Technology, 8010 Graz, AustriaInstitute of Timber Engineering and Wood Technology, Graz University of Technology, 8010 Graz, AustriaInstitute of Timber Engineering and Wood Technology, Graz University of Technology, 8010 Graz, AustriaInstitute of Timber Engineering and Wood Technology, Graz University of Technology, 8010 Graz, AustriaCross laminated timber (CLT), with its typical orthogonal layering and exposure to out-of-plane bending, develops inherent rolling shear stresses. These stresses need to be checked during the ultimate limit state design process. With the ongoing revision of Eurocode 5, a discussion regarding the characteristic value of the rolling shear strength of CLT has arisen. One obstacle in the discussion is seen in the lack of harmonized regulations concerning how to determine rolling shear properties. This circumstance manifests in the greatly diverging test results of different institutions testing the rolling shear strength. The paper at hand aims to propose a candidate for such harmonized regulations. To achieve this, the most common test setups, such as the inclined shear test, three- and four-point bending tests, etc., were numerically and experimentally investigated. Within the numerical investigations, a comparison of the most common calculation methods (Timoshenko beam theory, modified γ-method, Shear Analogy Method, and Finite Element Analysis) for evaluating rolling shear stresses was included. In the experimental program, parameters such as the specimen width, number, and thickness of the cross layer(s), shear length, optional reinforcement against the stresses perpendicular to the grain, and the overall test setup were varied. It was found that the used test setups themselves and the area of the cross layer(s) (shear length, number, and thickness of the cross layer(s)) have a major impact on the rolling shear strength. In contrast, no effect was found from the calculation methods. Based on these findings and on a database of approx. 300 four-point bending rolling shear tests on CLT specimens from five well-established CLT manufacturers, a model for the regulation of the rolling shear strength of CLT is proposed, in combination with a corresponding four-point bending test setup. Afterwards, with two additionally conducted four-point bending test series, the proposed model is successfully validated. The conclusions and recommendations in respect to the test setup (four-point bending), evaluation procedure (Timoshenko beam theory), reference characteristic rolling shear strength, and the model, which allows adapting the reference rolling shear strength to individual conditions, are seen as a worthy basis for a more objective discussion on this topic.https://www.mdpi.com/2075-5309/13/11/2831rolling shear strengthcross laminated timberCLTthree- and four-point bending testinclined compression shear testsize effect |
| spellingShingle | David Glasner Andreas Ringhofer Reinhard Brandner Gerhard Schickhofer Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design Buildings rolling shear strength cross laminated timber CLT three- and four-point bending test inclined compression shear test size effect |
| title | Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design |
| title_full | Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design |
| title_fullStr | Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design |
| title_full_unstemmed | Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design |
| title_short | Rolling Shear Strength of Cross Laminated Timber (CLT)—Testing, Evaluation, and Design |
| title_sort | rolling shear strength of cross laminated timber clt testing evaluation and design |
| topic | rolling shear strength cross laminated timber CLT three- and four-point bending test inclined compression shear test size effect |
| url | https://www.mdpi.com/2075-5309/13/11/2831 |
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