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.
