Abdoli Farshid, Rashidi Maria, Rostampour-Haftkhani Akbar, Layeghi Mohammad, Ebrahimi Ghanbar
Department of Wood and Paper Science, Faculty of Natural Resources, University of Tarbiat Modares, Tehran 14117-13116, Iran.
Centre for Infrastructure Engineering, Western Sydney University, Sydney 2000, Australia.
Polymers (Basel). 2022 Jul 31;14(15):3129. doi: 10.3390/polym14153129.
Cross-laminated timber (CLT) can be used as an element in various parts of timber structures, such as bridges. Fast-growing hardwood species, like poplar, are useful in regions where there is a lack of wood resources. In this study, the withdrawal resistance of nine types of conventional fasteners (stainless-steel nails, concrete nails and screws, drywall screws, three types of partially and fully threaded wood screws, and two types of lag screws), with three loading directions (parallel to the grain, perpendicular to the surface, and tangential), and two layer arrangements (0-90-0° and 0-45-0°) in 3-ply CLTs made of poplar as a fast-growing species and fir as a common species in manufacturing of CLT was investigated. Lag screws (10 mm) displayed the highest withdrawal resistance (145.77 N), whereas steel nails had the lowest (13.13 N), according to the main effect analysis. Furthermore, fasteners loaded perpendicular to the grain (perpendicular to the surface and tangential) had higher withdrawal resistance than those loaded parallel to the grain (edge). In terms of the layer arrangement, fasteners in CLTs manufactured from poplar wood (0-45-0°) had the greatest withdrawal resistance, followed by CLTs manufactured from poplar wood in the (0-90-0°) arrangement, and finally, those made from fir wood in the (0-90-0°) arrangement. The fastener type had the most significant impact on the withdrawal resistance, so changing the fastener type from nails to screws increased it by about 5-11 times, which is consistent with other studies. The results showed that poplar, a fast-growth species, is a proper wood for manufacturing CLTs in terms of fastener withdrawal performance.
交叉层压木材（CLT）可作为木结构各个部分的构件，如桥梁。速生阔叶树种，如杨树，在木材资源匮乏的地区很有用。在本研究中，研究了九种传统紧固件（不锈钢钉、水泥钉和螺丝、干墙螺丝、三种部分和全螺纹木螺丝以及两种方头螺丝）在三个加载方向（平行于木纹、垂直于表面和切向）以及两种层排列方式（0-90-0°和0-45-0°）下，在以杨树（一种速生树种）和杉木（CLT制造中常用的树种）制成的三层CLT中的抗拔力。根据主效应分析，方头螺丝（10毫米）显示出最高的抗拔力（145.77牛），而钢钉的抗拔力最低（13.13牛）。此外，垂直于木纹加载（垂直于表面和切向）的紧固件比平行于木纹（边缘）加载的紧固件具有更高的抗拔力。就层排列而言，由杨木制成的CLT（0-45-0°）中的紧固件具有最大的抗拔力，其次是杨木制成的（0-90-0°）排列的CLT，最后是杉木制成的（0-90-0°）排列的CLT。紧固件类型对抗拔力的影响最为显著，因此将紧固件类型从钉子改为螺丝可使其增加约5至11倍，这与其他研究一致。结果表明，就紧固件抗拔性能而言，速生树种杨树是制造CLT的合适木材。
