The Behaviour of Built-up Thin-Walled Steel Structural Elements

冷成型钢结构构件是通过在室温下将金属板轧制或压制成型为结构形状而生产的。它们通常重量轻，具有高强度重量比，有利于更可持续的建筑解决方案。虽然传统上冷弯型钢构件一直用于次要的结构构件，但目前的趋势是越来越多地使用冷弯型钢产品作为主要构件，例如工业霍尔斯或多层住宅建筑的门式框架。这种演变对冷弯型钢结构构件的承载能力和跨度长度提出了越来越高的要求。因此，在实践中经常使用通过螺栓连接、铆接或螺纹连接将各个形状以结构上有效的配置连接在一起而形成的组合构件。然而，我们对这些组合结构元件的响应模式的基本理解落后于实践，并且在结构设计Eurocodies.The建议的研究的目的是调查冷弯组合截面的行为、强度和稳定性中完全缺乏适当的设计规则。将特别注意由连接点之间的单个横截面部件的屈曲与整个组合构件的各种不稳定性之间的相互作用引起的耦合不稳定性。因此，预计连接器间距将对承载能力产生关键影响。调查的第一阶段将包括对创新的组合横截面形状的实验研究。设想对组合柱和组合梁进行总共55次实验室试验。将通过使用有限元模拟进行详细的数值研究，改变相关参数，如横截面几何形状，连接器间距，连接器类型和材料特性，从而扩大所得数据集。在最后一步中，在研究的前几个阶段中获得的对组合冷弯型钢构件的行为的更多理解预计将最终导致开发安全准确的设计程序，并通过统计可靠性分析对可用数据进行验证的设计方程。

Cold-formed steel structural members are produced by rolling or press forming a metal sheet into a structural shape at room temperature. They are typically light-weight and possess a high strength-to-weight ratio, facilitating more sustainable construction solutions. Whilst traditionally cold-formed steel members have been used for structural elements of secondary importance, the current trend is to increasingly use cold-formed steel products as primary members, for instance in portal frames for industrial halls or in multi-storey residential buildings. This evolution puts increasing demands on cold-formed steel structural members in terms of load carrying capacity and span lengths. Built-up members, created by bolting, riveting or screwing individual shapes together in structurally efficient configurations, are therefore often used in practice. However, our fundamental understanding of the mode of response of these built-up structural elements is lagging behind practice, and appropriate design rules are completely lacking in the structural design Eurocodes.The aim of the proposed research is to investigate the behaviour, strength and stability of cold-formed built-up sections. Particular attention will be paid to coupled instabilities resulting from an interaction between buckling of the individual cross-section components in between connector points and the various instabilities of the full built-up member. It is thereby expected that the connector spacing will have a crucial effect on the load carrying capacity. A first stage of the investigation will consist of experimental investigations on innovative built-up cross-sectional shapes. A total of 55 laboratory tests on built-up columns and beams are envisaged. The resulting dataset will be augmented by carrying out detailed numerical studies using finite element simulations, varying relevant parameters such as the cross-section geometry, the connector spacing, the connector type and the material properties. In a final step, the increased understanding of the behaviour of built-up cold-formed steel members gained in the previous stages of the research is expected to culminate in the development of a safe an accurate design procedure, with design equations that are verified against the available data through statistical reliability analysis.