2022 Fiscal Year Research-status Report
Wrapping LVL as a wood-only timber frame joint inspired by the model of trees' stem-branch junction
| Project/Area Number |
22K20463
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| Research Institution | Akita Prefectural University |
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Principal Investigator |
Firas HAWASLY 秋田県立大学, 木材高度加工研究所, 特任助教 (10962839)
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| Project Period (FY) |
2022-08-31 – 2024-03-31
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| Keywords | Wrapping LVL / Veneer reinforcement / Stem-branch junction / Timber frame joint / Wood-only joint |
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| Outline of Annual Research Achievements |
The performed simplified experiments of adding 45 degrees cross-laminated veneer layers as outer reinforcements to three sides of the flat-wise loaded laminated-core material with a thickness of 8% of the total depth, showed the significant enhancement in moment capacity, doubling the performance of the unreinforced core material in flat-wise and edge-wise loading conditions and slightly surpassing the performance of solid wood.
These initial findings promise to introduce enhanced bent-laminated elements capable of seamlessly transferring loads between two linear sections adequately and homogeneously and approaching the intended aim of a structurally sound, wood- only, moment-resistant constructional application at timber joints. However, the intended continuous wrapping approach of the addressed application proved to be technically challenging, specifically on curved surfaces; hence, much simpler applications of wrapped bent veneers with the same intended performance have been developed. Furthermore, regarding the parameters of adhesive type, thickness, wrapping angle, and material of the reinforcement layers, a specially developed shear/tension testing jig was manufactured to achieve the optimal combination. The fixture was adapted from the Arcan et al. shear fixture; ranging from pure shear to pure tension in 15 degrees increments and at variable thicknesses, and will facilitate the analytical parametric design of the desired performance.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Due to the development of alternative wrapping and application approaches and the manufacturing of necessary specimen for the tests.
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| Strategy for Future Research Activity |
Further experimentation will be carried on linear sections of flat-wise laminated material, as well as on bent-laminated material in curvature-increasing and decreasing setups. Along with defining the strain distribution across the loaded surfaces and optimizing the necessary reinforcement addition. Furthermore, the shear/tension tests of the wrapping material will be analyzed numerically to aid in achieving the desired structural application.
Further applications of the simple linear and bent members will be developed towards the intended implementation of a wood-only moment resistant timber frame joint.
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| Causes of Carryover |
The development of different approaches hindered the active use of the funds, in addition to the utilization of other internal funds and the use of already purchased and available materials at the research institute.
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