轻钢-速生木自攻螺钉连接构件抗拔性能研究

陈志华; 冯浩; 刘佳迪

doi:10.13206/j.gjgS23061401

轻钢-速生木自攻螺钉连接构件抗拔性能研究

doi: 10.13206/j.gjgS23061401

陈志华^1,2,
冯浩¹,
刘佳迪^1, ,

1. 天津大学建筑工程学院, 天津 300072;
2. 天津大学滨海土木工程结构与安全教育部重点实验室, 天津 300072

基金项目:

国家重点研发计划(2019YFD11010000)

详细信息

作者简介:
陈志华,男,1966年出生,博士,教授

通讯作者:
刘佳迪,男,1986年出生,博士,副教授,jdliu@tju.edu.cn。

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- 文章访问数: 199
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- 被引次数: 0
出版历程
- 收稿日期: 2023-06-14
- 网络出版日期: 2023-10-20

Research on the Pull-out Behavior of Light Gauge Steel-Fast Growing Timber with Self-Tapping Screw Connection

Zhihua Chen^1,2,
Hao Feng¹,
Jiadi Liu^{1
, ,}

1. School of Civil Engineering, Tianjin University, Tianjin 300072, China;
2. Key Laboratory of the Ministry of Education on Binhai Civil Engineering Structure and Security, Tianjin University, Tianjin 300072, China

摘要

摘要: 将木材应用到建筑结构当中,既可以发挥木材环保的特性,又能够使建筑富有美感。我国的速生木材产量丰富,应用到建筑当中可以减少对进口木材的依赖,降低施工成本。但是由于速生木强度较弱、结构疏松不均匀,在建筑中应用有一定的局限性,引入轻钢可以削弱木材的天然缺陷,同时木材也可以解决轻钢稳定性不足的问题。轻钢-速生木结构是将钢材引入到传统木结构中的一种新型建筑结构,它兼顾了钢材和木材两种材料的优点,在村镇住宅等建筑结构中具有一定的应用前景。由于自攻螺钉连接的轻钢-速生木结构的力学行为受到自攻螺钉抗拔性能的影响较大,同时现有研究中对此类结构的自攻螺钉抗拔性能相关研究并不完善。因此对由国产速生树种杉木与Q235级薄钢板构成的自攻螺钉钢木组合构件进行了抗拔试验,将薄钢板与木块用自攻螺钉连接起来放置到自制夹具当中,运用万能试验机将螺钉拔出,用以研究其力学性能。试验过程中选取了钢板厚度和纹理方向两个重要试验参数,得到了自攻螺钉的破坏模式、抗拔极限荷载和延性。研究结果表明:试件的破坏模式均为自攻螺钉拔出破坏,钉子拔出后螺纹有明显损坏,螺纹内有铁屑和木屑堆积,钢板存在扩孔以及鼓曲现象;当螺钉垂直于顺纹方向拔出时,试件的离散性较低,同时增加钢板厚度也可以降低离散性;轻钢的加入可以显著提高构件的极限荷载,提高节点的受力性能;钢板对端面极限荷载影响要大于另外两个方向;相同条件下,端面极限荷载要低于另外两个方向,并随着钢板厚度的增加差距逐渐降低;相同条件下,自攻螺钉从径向以及弦向拔出时,承载能力差别不大,两个方向极限荷载差距不超过10%;钢板厚度为1.5 mm时,试件相较于其他钢板厚度试件表现出较好的延性,但是试件总体延性系数低于3,延性系数较小。最后,基于欧洲木结构设计规范和我国GB 50017—2017《钢结构设计标准》,提出了适用于自攻螺钉连接的杉木与薄钢板组成的钢木组合构件的抗拔承载力计算公式,公式误差均在15%以内,验证了公式的适用性和准确性。
- 自攻螺钉 /
- 速生木 /
- 钢木组合构件 /
- 抗拔性能 /
- 设计方法
Abstract: The application of timber to buildings can bring out the environmental characteristics of timber and make the building aesthetically. Fast-growing timber is abundant in China and can be used in the construction to reduce dependence on imported timber and reduce construction costs. However, due to the weak strength and uneven structure of fast-growing timber, there are some limitations in the application of construction. The introduction of light gauge steel can weaken the natural defects of timber, while timber can also solve the problem of instability of light gauge steel. Light gauge steel-fast growing timber structure is a new type of building structure that introduces steel into timber structure. It has the advantages of both steel and timber, and has certain prospects for application in building structures such as village houses. Since the mechanical behavior of self-tapping screw-connected light gauge steel-fast growing timber structures is influenced by the pullout resistance of self-tapping screws, and the existing studies on the pull-out resistance of self-tapping screws for such structures are not well studied. Therefore, a nail joint pullout test was conducted on steel-timber composite members made of domestic fast-growing fir timber and thin steel plates graded Q235. The thin steel plates and timber blocks were connected with self-tapping screws and placed in a homemade fixture. Using a testing machine to pull out the screws from the specimens to study their mechanical properties. Two important experimental parameters, including the thickness of the steel plate and the grain direction, were selected during the test to obtain the failure mode, ultimate load, and the ductility of the self-tapping screws. The results show that the failure mode of the specimens is all the damage of self-tapping screws pull-out. The threads are obviously damaged after the nails are pulled out. There is an accumulation of iron and timber chips in the threads, and the steel plate reamed and bulged. The dispersion of the specimens is low when the screws are pulled out perpendicularly in the direction of the grain, and the dispersion can be reduced by increasing the thickness of the steel plate. Simultaneity, the addition of light steel can significantly increase the ultimate load of specimens. The ultimate load at the end is lower than that in the other two directions, and the difference decreases gradually with the increase of steel plate thickness under the same conditions. When the self-tapping screws are pulled out from the radial direction and the chordal direction, the difference of load carrying capacity is not much, and the difference of ultimate load in the two directions was within 10%. When the steel plate thickness is 1.5 mm, the specimen shows better ductility than other specimens, while the overall ductility coefficient of the specimens is lower than 3. Finally, based on the European Code for the design of timber structures and Chinese Code for the design of steel structures, a formula to calculate the pull-out load capacity of steel-timber composite members composed of fir timber and thin steel plates connected by self-tapping screws was proposed, and the error of the formula was within 15%, which verified the applicability and accuracy of the formula.
- self-tapping screws /
- fast growing timber /
- steel-timber composite members /
- pull-out behavior /
- design method

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参考文献(21)

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