Files and links (1)
Published VersionCC BY V4.0, Open Access
Journal article
The importance of wood relaxation when studying nail withdrawal capacity
Case Studies in Construction Materials, Vol.23, pp.1-15
2025
Abstract
Nails are among the most widely utilised fasteners in timber construction. Nail withdrawal capacity (NWC) has been extensively studied; however, the specific mechanisms by which moisture affects NWC remain unclear. In addition, the effects of wood relaxation on NWC in durability studies are often overlooked, introducing potential errors. This study assessed the impacts of wood moisture content (MC) and relaxation on NWC, with investigations on potential affecting mechanisms. The key innovation of this study lies in the mechanistic explanation of NWC changes using Coulomb’s Law of Friction, supported by microscopy-based characterisation of the wood–nail interface. Smooth-shank nails driven into radiata pine conditioned to 9 %, 12 %, and 18 % MC were tested up to 28 days after driving. Affecting mechanisms were investigated using stress relaxation tests, confocal microscopy, and scanning electron microscopy (SEM). NWC was significantly reduced by 41 % and 44 % 28 days after driving at 9 % and 12 % MC (n = 30), respectively. In contrast, NWC increased by 11 % at 18 % MC. The time required to stabilise NWC in all conditions was 14 days. Stress relaxation tests, confocal microscopy, and SEM results suggest the NWC losses at 9 % and 12 % MC were caused by wood relaxation, while the increase at 18 % MC might be attributed to softer wood fibres, suspected metal oxidation or corrosion, or trapped wood fibres on the nail surfaces. These findings not only clarify the mechanisms driving NWC changes but also highlight the importance of accounting for wood relaxation in experimental design and durability assessment.
Details
- Title
- The importance of wood relaxation when studying nail withdrawal capacity
- Authors
- Yuhao Zhang (Corresponding Author) - The University of QueenslandLisa-Mareike Ottenhaus - University of the Sunshine Coast, Queensland, National Centre for Timber Durability and Design LifeTripti Singh - University of the Sunshine Coast, Queensland, National Centre for Timber Durability and Design LifeLuis Yermán - The University of Queensland
- Publication details
- Case Studies in Construction Materials, Vol.23, pp.1-15
- Publisher
- Elseveir BV
- Date published
- 2025
- DOI
- 10.1016/j.cscm.2025.e05421
- ISSN
- 2214-5095
- Copyright note
- © 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
- Data Availability
- Data will be made available on request.
- Grant note
- This research was jointly funded by the School of Civil Engineering of The University of Queensland and the National Centre for Timber Durability and Design Life.
- Organisation Unit
- National Centre for Timber Durability and Design Life
- Language
- English
- Record Identifier
- 991175216902621
- Output Type
- Journal article
Metrics
1 File views/ downloads
27 Record Views