‘Rope effect’ mechanism of self-tapping screws as reinforcement on dowel-type connections

Zhang, Cong; Jung, Kiho; Harris, Richard; Chang, Wen‐Shao

doi:10.1680/jstbu.20.00204

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…Within the scope of this research work, the authors improved the moment-resisting capacity of glulam connections using partially threaded screws on portal frames [26] and glulam connections with artificial cracks [27]. Screw reinforcement can control wood splitting and this ability is governed by the pull-through and withdrawal capacity of the screw and the similar 'rope effect' is discussed [28]. The capability of self-tapping screws to reinforce artificially damaged connections was also investigated [29].…”

Section: Introductionmentioning

confidence: 99%

Reinforcement of Timber Dowel-Type Connections Using Self-Tapping Screws and the Influence of Thread Configurations

Zhang

Huang

et al. 2023

Forests

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The application of self-tapping screws as reinforcement on glulam connections has been proven effective. However, the implication of different thread configurations on the effectiveness of reinforcement remains unknown. This paper conducted experiments using screws with various thread configurations in embedment-strength tests and tensile connection tests. Results show that self-tapping screws with one third of thread achieved similar improvement in the embedment strength and mechanical properties of connections as fully threaded screws. This implies that properly reducing the thread length on self-tapping screws ensures easier screw installation than using fully threaded screws. The influence of screw-to-dowel distance was also investigated and two distances (0.5 d and 1 d) were adopted, with ‘d’ being the diameter of the dowel. The difference in embedment strength due to different screw-to-dowel distances was insignificant. The group with screws placed in contact (0.5 d) with the dowel achieved 5% higher embedment strength than the group with screws placed at a 1 d distance. The connection tests showed good agreement with the embedment-strength tests. This confirms that self-tapping screws with reduced thread can enhance the load-carrying capacity and ductility of connections to a level similar to connections reinforced by fully threaded screws.

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Section: Introductionmentioning

confidence: 99%

Reinforcement of Timber Dowel-Type Connections Using Self-Tapping Screws and the Influence of Thread Configurations

Zhang

Huang

et al. 2023

Forests

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Editorial

Aslani

2023

Proceedings of the Institution of Civil Engineers - Structures

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Comparison of Self-Tapping Screws and Bamboo Nails in Reinforcing the Zuo-Dou Connections in Traditional Oriental Timber Frames of Asia

Yeh

Wang

et al. 2023

Buildings

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This paper is focused on the retrofitting techniques of Zuo-Dou connections in Dieh-Dou timber frames in Far East Asia. The target is to develop appropriate techniques for the reinforcement and maintenance of the wooden cultural heritage. A series of full-scale tests are intended for the evaluation of the rotational and shear characteristics of the various retrofitting techniques for the Zuo-Dou joints. These retrofitting techniques are conceived by this study based on the principles of the conservation of cultural heritage. The reversible materials, invisible layouts, and structurally efficient schemes are taken into account to figure out the reinforcement strategies. Regarding the conservation targets, this study applies the self-tapping screw (STS) and the bamboo nail for reinforcement. Corresponding to the loading circumstances, moment- and shear-constraining schemes are developed. The STS and the bamboo nail are applied by means of moment- or shear-constraining strategies. Then, rotational and shear tests are carried out to estimate the structural efficiency of the conceived retrofitting techniques. With the appropriate schemes, the STS and the bamboo nail contribute to the enhancement of the structural performance of the Zuo-Dou connection. The STS in a moment-constraining profile can ameliorate the Zuo-Dou’s rotational behaviour. As far as post retrofitting and preventing reinforcing are concerned, the STS reveals considerable structural efficiency. The bamboo nail in a shear-constraining scheme can increase the shear capacity of the Zuo-Dou joint. Besides the quantitative outcomes, these retrofitting techniques exhibit ductility and enhance the deformation processes of the connections. With the alternative fasteners, the slump or vibration during the deformation becomes moderate and the severe damages, such as rocking or block shear failure, are alleviated. The techniques and associated materials used in this study exhibit compatibility and feasibility for constraining the rotation, deformation, and crack of the Zuo-Dou connection. These effects are helpful for retaining the joints’ structural behaviour and contribute to the conservation of traditional timber constructions.

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‘Rope effect’ mechanism of self-tapping screws as reinforcement on dowel-type connections

Cited by 3 publications

References 7 publications

Reinforcement of Timber Dowel-Type Connections Using Self-Tapping Screws and the Influence of Thread Configurations

Reinforcement of Timber Dowel-Type Connections Using Self-Tapping Screws and the Influence of Thread Configurations

Editorial

Comparison of Self-Tapping Screws and Bamboo Nails in Reinforcing the Zuo-Dou Connections in Traditional Oriental Timber Frames of Asia

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