Development of stability design guidelines for modern I-shaped welded steel girders in Canada

北美的许多建筑结构和桥梁都是用焊接钢梁建造的，以抵抗重力 载荷这种梁的设计通常由其稳定性决定;然而，各种参数可以 影响其稳定性响应，包括横截面特性、端部和载荷条件、内建应力 和初始几何缺陷。目前的加拿大设计标准得到了研究的支持， 必然代表现代梁的设计和制造实践。过去实验的有效性 研究和相应的数值模拟是值得怀疑的，因为他们依赖于小规模的测试 标本和制造工艺不再实行。此外，很少有研究详细 影响参数的量化。为了更好地了解现代焊接钢梁的稳定性， 设计人员需要根据反映设计中构件实际行为的数据改进指南 载荷我们的研究项目集中在四个关键目标：1）彻底测量振幅和模式 在当代制造和焊接过程中产生的残余应力; 2） 根据以下影响评估钢桥和建筑物中焊接梁的稳定性要求： 残余应力; 3）评估加拿大现行的I形焊接钢稳定性设计要求 梁;以及4）为加拿大稳定性标准的更改生成设计建议 钢结构和桥梁设计的要求。为了实现这些目标，研究团队将执行 全尺寸实验室实验，并采用数值模拟。我们还将提供改进的设计工具， 结构工程师的日常工作，从而更安全的结构和降低建筑成本。

Many building structures and bridges in North America are built with welded steel girders to resist gravity loads. The design of such girders is typically governed by their stability; however, various parameters can affect their stability response, including cross-sectional properties, end and loading conditions, built-in stresses and initial geometric imperfections. Current Canadian design standards are supported by studies that do not necessarily represent the design and fabrication practice of modern girders. The validity of past experimental studies and corresponding numerical simulations is questionable because of their reliance on small-scale test specimens and fabrication processes that are no longer practiced. Additionally, few studies include detailed quantification of the influential parameters. To better understand stability of modern welded steel girders, designers need improved guidelines based on data that reflect the actual behaviour of the member under design loads. Our research project focuses on four key objectives: 1) to thoroughly measure the amplitude and pattern of residual stresses that develop in the course of contemporary manufacturing and welding processes; 2) to evaluate the stability requirements for welded girders in steel bridges and buildings in light of the effect of residual stresses; 3) to evaluate current Canadian stability design requirements for I-shaped welded steel girders; and 4) to generate design recommendations for changes to Canadian standards for stability requirements in steel construction and bridge design. To achieve these aims, the research team will perform full-scale lab experiments and employ numerical modelling. We will also provide improved design tools to structural engineers for their daily work, resulting in safer structures and reduced construction costs.