Exploring A Novel Buckling Mitigation Technique for Thin-Walled Steel Structures Using Pultruded FRP Sections

研究的主要目标是探索一种新的薄壁钢结构加固方法，该方法将拉挤纤维增强聚合物截面粘结在脆弱的细长板上，以抑制局部屈曲破坏模式。该方法依靠挤压截面的面外抗弯刚度来减小薄钢板的细长细度。通过27个单调加载试件和12个循环加载试件的试验，验证了该方法的有效性。实验程序将研究设计参数的影响，如接触面积、环氧树脂的性质、初始板长细比和热条件对使用新技术可实现的强度增益的影响。将开发能够捕捉增强板与增强纤维增强聚合物截面之间脱键的建模方法。环氧树脂退化模型将被开发并用于建立预测强度增益的方法，并为工程师开发简化的设计工具。本研究提出了利用纤维增强聚合物复合材料的面外刚度对钢结构进行结构加固的新概念。如果成功，这项研究将允许使用廉价、快速和易于应用的拉挤截面来加强有缺陷的薄壁钢结构，而不会引入通常焊接钢加强筋引起的不利应力集中。本文的研究成果对日益恶化的薄壁桥梁构件进行加固，提高其结构性能具有重要意义。将从已建立的机构伙伴关系中招收一名博士研究生，优先考虑来自代表性不足群体的高素质学生。工程专业本科生将参与项目的实验部分，并协助开发开放日活动和高中招生参观的示范材料。研究结果将通过国际会议、期刊出版物、继续教育讲习班和一个总结主要研究成果的互动网站广泛传播。

The main goal of the research is to explore a new strengthening approach for thin-walled steel structures in which pultruded fiber reinforced polymer sections are bonded to vulnerable slender plates to inhibit local buckling failure modes. The approach relies on the out-of-plane flexural rigidity of the pultruded section to reduce the slenderness of thin steel plates. It is proposed to test about 27 monotonically loaded and 12 cyclically loaded specimens to validate the effectiveness of the new approach. The experimental program will study the effects of design parameters such as contact area, properties of epoxy, initial plate slenderness, and thermal conditions on the strength gains achievable using the new technique. Modeling approaches that can capture the de-bonding between the strengthened plate and the strengthening fiber reinforced polymer section will be developed. Epoxy degeneration models will be developed and used to establish a methodology for predicting strength gains, and to develop simplified design tools for engineers. This research introduces a new concept of utilizing the out-of-plane stiffness of fiber reinforced polymer composite materials for structural strengthening of steel structures. If successful, this research will allow strengthening of deficient thin-walled steel structures using inexpensive, fast, and easy-to-apply pultruded sections without introducing adverse stress concentrations that are caused by usual welding of steel stiffeners. The outcome of this research would especially help in strengthening the deteriorating thin-walled bridge components to enhance their structural performance. One Ph.D. student with preference given to highly qualified students from underrepresented groups will be recruited from established institutional partnerships. Undergraduate engineering students will be involved in the experimental portion of the project and will assist in developing demonstration materials for open-day activities and high-school recruitment visits. The results will be widely disseminated through international conferences, journal publications, continuing education workshops, and an interactive web site that summarizes the major research findings.