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

研究的主要目的是探索一种新的薄壁钢结构加固方法，其中拉挤纤维增强聚合物型材被粘结到脆弱的细长板，以抑制局部屈曲失效模式。该方法依赖于拉挤型材的平面外抗弯刚度来减小薄钢板的细长度。 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。实验计划将研究设计参数的影响，如接触面积，环氧树脂的性能，初始板细长度，和热条件的强度增益可实现使用新技术。建模方法，可以捕捉到加强板和加强纤维增强聚合物部分之间的脱粘将被开发。将开发环氧树脂退化模型，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。如果成功的话，这项研究将允许使用廉价，快速，易于应用的拉挤型材来加强有缺陷的薄壁钢结构，而不会引入通常焊接钢加劲肋所引起的不利应力集中。本研究之成果将特别有助于加强恶化的薄壁桥梁构件，以提高其结构性能。一个博士将从已建立机构伙伴关系中招聘学生，优先考虑来自代表性不足群体的高素质学生。本科工程专业的学生将参与该项目的实验部分，并将协助开发开放日活动和高中招生访问的演示材料。研究结果将通过国际会议、期刊出版物、继续教育讲习班和总结主要研究结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.