陈国, 于云飞, 李祥, 何彬, 郑乃浩, 赵欢. 定向刨花板加固腹板开洞竹木工字梁力学性能研究[J]. 农业工程学报, 2018, 34(23): 260-266. DOI: 10.11975/j.issn.1002-6819.2018.23.034
    引用本文: 陈国, 于云飞, 李祥, 何彬, 郑乃浩, 赵欢. 定向刨花板加固腹板开洞竹木工字梁力学性能研究[J]. 农业工程学报, 2018, 34(23): 260-266. DOI: 10.11975/j.issn.1002-6819.2018.23.034
    Chen Guo, Yu Yunfei, Li Xiang, He Bin, Zheng Naihao, Zhao Huan. Study on laminated bamboo lumber-wood I shaped joist with web opening reinforced by oriented stand board plates plates[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(23): 260-266. DOI: 10.11975/j.issn.1002-6819.2018.23.034
    Citation: Chen Guo, Yu Yunfei, Li Xiang, He Bin, Zheng Naihao, Zhao Huan. Study on laminated bamboo lumber-wood I shaped joist with web opening reinforced by oriented stand board plates plates[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(23): 260-266. DOI: 10.11975/j.issn.1002-6819.2018.23.034

    定向刨花板加固腹板开洞竹木工字梁力学性能研究

    Study on laminated bamboo lumber-wood I shaped joist with web opening reinforced by oriented stand board plates plates

    • 摘要: 为研究定向刨花板(oriented strand board,OSB)加固腹板开洞的竹木工字梁的力学性能,揭示其受力破坏机理。以孔径与腹板高度的比值(d/hw)和补强板型为参数,制作并测试了42根竹木工字梁,考察测试过程中的破坏形态、弯曲变形性能,分析各因素对工字梁力学性能的影响规律。结果表明,当孔径较小(d/hw≤25%)时,试件的破坏形态以翼缘内OSB层裂和腹板剪切破坏为主,孔洞对开洞梁承载力和刚度的影响较小,可忽略不计。当孔径较大(d/hw>25%)时,破坏形态以洞口周边受拉和受压破坏为主,随着孔洞直径d增加,孔洞的不利影响愈发明显,开洞梁的承载能力呈下降趋势,但对梁的刚度影响较小。OSB补强板能有效约束孔角裂缝开展,加固后的开洞梁的开裂荷载、正常使用极限状态荷载和承载能力极限状态荷载较未加固开洞梁明显提高,平均提高52.9%、12.1%和28.2%。但OSB补强板对开洞梁抗弯刚度的改善作用不明显,平均提高仅为11.5%。承载力和刚度的提高幅度与补强板类型密切相关,其中,套环定向刨花板(collar oriented strand board,C-OSB)增强效果最好、双U型定向刨花板(two U shaped oriented strand board,TU-OSB)次之,U型定向刨花板(U shaped oriented strand board,U-OSB)最差。C-OSB适合于管道施工前对开洞梁进行加固,而U-OSB和TU-OSB适合加固d/hw不大于75%的开洞梁。粘贴OSB加固开洞竹木工字梁是一种有效的加固方法。

       

      Abstract: Abstract: Bamboo is considered as one of fastest-growing plants in the world, widely distributed in South America and Southeast Asia. Especially in southern China, the planting area and output of bamboo ranks first in the world. For decades, raw bamboo has been successfully used in civil construction, often in the form of beams, columns, rafters and so on. However, several problems arise in practical applications and need to be solved, such as thin-walled hollow, irregular shape, easy to crack when exposure to moisture alternation frequently. Laminated bamboo lumber (LBL) is considered as a promising green engineering material in modern bamboo construction, due to higher strength/weight ratio and more rapid renewability than common wood. Oriented strand board (OSB) is mainly made from thin wood flakes sliced from small-diameter, fast-growing trees. Due to good cost-efficiency ratio, the OSB panel has been used as webs of wood I-joist, floor sheathing, roof sheathing, and so on. An OSB webbed laminated bamboo lumber I shaped joist is introduced, which consists of four LBL flanges and OSB web. The LBL is attached to the OSB by adhesive and nails spaced at 150 mm in center. To study the capacity, deformation performance and failure mechanism of the OSB webbed bamboo I-joists with circular web opening, 42 joints with/without web opening are tested. Among them, 12 joists with web opening without strengthened, 27 joists with web opening are retrofitted by collar oriented strand board (C-OSB), two U shaped oriented strand board (TU-OSB) or U shaped oriented strand board (U-OSB) and 3 joists without opening for comparison. Results show that the effect of joists with hole diameter to web height less than 25% are negligible, no repairs are required. With the increase of ratio of the hole size to web height (d/hw), the peak load capacity and stiffness of the joists with big opening (d/hw≥50%) decrease significantly, and the joists failed in web shear failure around the opening, mainly in compression and tension failure. The cracking loads strengthened by OSB plates increases by 52.9%, the loads at allowable deflection increase by 12.1% on average, and the ultimate loads increase by 28.2%, respectively. The increase of carrying capacity is closely related to the types of OSB plates, and the C-OSB plate is the biggest. Also, the OSB plates can improve the initial stiffness, increased only by 11.5% on average. The improvement of C-OSB on mechanical performance of composite joists is most effective, TU-OSB less and U-OSB least. It is evident that the C-OSB has the greatest enhancement effectiveness on joist with opening, however, the selection of OSB plates for reinforcement should be considered comprehensively in practical applications. The C-OSB is suitable to retrofit joist with opening prior to the installation of the service pipes, while the TU-OSB and U-OSB can be used to reinforce the joist with the opening diameter less than 75% without removing the pipeline facilities. The results indicate that the OSB webbed LBL I joist has excellent mechanical performance which can be used for the bending members in bamboo structures and wood structure.

       

    /

    返回文章
    返回