Abstract This paper describes an experimental and numerical investigation to study the flexural capacity of back-to-back gapped built-up cold-formed steel (CFS) channel sections under four-point bending. The gap between the back-to-back channels was formed through intermediate link-channels which were screwed to the webs of the back-to-back channels. A total of 90 results comprising 18 laboratory tests and 72 finite element (FE) analysis results are reported on the flexural capacity of back-to-back gapped built-up CFS channel sections under four-point bending. Three different types of channels were considered to form the built-up channels: plain channels, channels with one web stiffener and channels with two web stiffeners. Two different beam spans as 1000 mm and 2000 mm were tested. Initial geometric imperfections were also measured prior to bending tests for all test specimens. A nonlinear FE model was then developed, the results of which showed good agreement against the laboratory test results. Using the validated FE model, an extensive parametric study was conducted to investigate the effects of web stiffeners and link-channel spacing on the flexural capacity of such gapped built-up beams. It is shown that design in accordance with the American Iron and Steel Institute, AISI (2016) and Australia/New-Zealand standards, AS/NZS (2018) can be conservative by as much as 27%. The flexural capacity of back-to-back gapped built-up sections with two web stiffeners was increased by 10% on average, when compared to the capacity of gapped built-up beams with plain channel sections.

中文翻译：

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包括腹板加劲肋的有间隙组合冷弯型钢槽钢截面的抗弯能力

摘要 本文描述了一项实验和数值研究，以研究背对背有间隙的组合冷弯型钢 (CFS) 通道截面在四点弯曲下的抗弯能力。背对背通道之间的间隙是通过中间连接通道形成的，中间连接通道被拧到背对背通道的腹板上。总共 90 个结果，包括 18 个实验室测试和 72 个有限元 (FE) 分析结果，报告了在四点弯曲下背对背有间隙的组合 CFS 通道截面的弯曲能力。考虑了三种不同类型的通道来形成组合通道：平面通道、具有一个腹板加强筋的通道和具有两个腹板加强筋的通道。测试了 1000 毫米和 2000 毫米两种不同的梁跨度。在对所有试样进行弯曲试验之前，还测量了初始几何缺陷。然后开发了非线性有限元模型，其结果与实验室测试结果非常吻合。使用经过验证的有限元模型，进行了广泛的参数研究，以研究腹板加劲肋和连接槽间距对此类有间隙组合梁的抗弯能力的影响。结果表明，按照美国钢铁协会、AISI（2016）和澳大利亚/新西兰标准的设计，AS/NZS（2018）可以保守多达27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。然后开发了非线性有限元模型，其结果与实验室测试结果非常吻合。使用经过验证的有限元模型，进行了广泛的参数研究，以研究腹板加劲肋和连接槽间距对这种有间隙的组合梁的抗弯能力的影响。结果表明，按照美国钢铁协会、AISI（2016）和澳大利亚/新西兰标准的设计，AS/NZS（2018）可以保守多达27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。然后开发了非线性有限元模型，其结果与实验室测试结果非常吻合。使用经过验证的有限元模型，进行了广泛的参数研究，以研究腹板加劲肋和连接槽间距对这种有间隙的组合梁的抗弯能力的影响。结果表明，按照美国钢铁协会、AISI（2016）和澳大利亚/新西兰标准的设计，AS/NZS（2018）可以保守多达27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。进行了广泛的参数研究，以研究腹板加劲肋和连接槽间距对这种有间隙的组合梁的抗弯能力的影响。结果表明，按照美国钢铁协会、AISI（2016）和澳大利亚/新西兰标准的设计，AS/NZS（2018）可以保守多达27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。进行了广泛的参数研究，以研究腹板加劲肋和连接槽间距对这种有间隙的组合梁的抗弯能力的影响。结果表明，按照美国钢铁协会、AISI（2016）和澳大利亚/新西兰标准的设计，AS/NZS（2018）可以保守多达27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。AS/NZS (2018) 可以保守多达 27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。AS/NZS (2018) 可以保守多达 27%。与具有普通通道截面的有间隙组合梁的抗弯能力相比，具有两个腹板加劲肋的背对背有间隙组合梁的抗弯能力平均增加了 10%。