Study on Reinforcement Method of Upper Flange of Steel Girders Using CFRP Moulded plates

Currently, large-scale replacement projects are underway in Japan to replace slabs, leading to an increasing demand for steel girder reinforcement. However, the upper flange must be reinforced from below due to the presence of slabs on the upper surface. Recently, carbon fiber has been used as a reinforcement material, but the vertical stiffeners installed beneath the upper flange hinder the continuous application of carbon fiber along the girder axis. The study proposed a reinforcement method for the underside of the upper flange, even in areas with vertical stiffeners, by bonding CFRP moulded plates to bypass the vertical stiffeners. Bending tests were performed on steel girder specimens reinforced using the proposed method to evaluate its reinforcement effectiveness. As a result, a reduction in stress on the upper flange was confirmed, even in locations where the vertical stiffener was present.