Abstract
To solve the problem of increased weight in steel underdeck panel construction for RC slabs, we are developing a strengthening method using FRP girders, which are lightweight and easy to construct, are placed in a grid configuration from the underside of the RC slab. The FRP girders are planned to be applied to the I-shaped HFRP girders consisting of pultruded carbon fiber and glass fiber, and double web GFRP girders consisting of glass fibers. In this study, three- and four-point bending loading tests were conducted on full-scale FRP girders to experimentally investigate their bending properties such as bending strength, failure modes, and deflection, in preparation for the practical use of FRP girders for reinforcing RC slabs. The results showed that the FRP girders were safe enough for the design loads and could be applied to reinforcement of RC slabs. Also, the anisotropic material properties of the FRP girders were converted into isotropic ones, and vertical displacements were calculated by FEM analysis using shell elements based on isotropic materials and beam theory. The results showed that the experimental values could be evaluated with high accuracy.
