Investigation of Bending Behaviors of GFRP-Strengthened Steel RHS Profiles with Experimental and Numerical Models

Abstract

The contribution of GFRP (glass fiber reinforced polymer) fabric to the bending behavior of steel RHS (rectangular hollow section) beams was investigated by experimental and numerical studies. In the first part of the study, small-scale RHS profiles were strengthened with GFRP fabrics in ten different configurations in the experimental study. The bending behavior of the profiles was determined by three-point bending tests, and the best strengthening configuration was decided. The numerical models were verified with the experimental results. In the second part, real-size RHS beams were strengthened with the optimum strengthening configuration. In the results of the study, it was determined that the U-shaped strengthening provided the maximum contribution to the RHS beams bending behavior. The minimum GFRP size to be used in strengthening is important, as an insufficient GFRP length leads to GFRP failure, and the number of layers should be increased for more load capacity. A total of 25% of the net beam span was determined to be the minimum GRFP length. In full-size beams, a double-layer GFRP increased the maximum load-bearing capacity by 7%. Formulas were obtained to determine the contribution of single and double-layered U-shaped GFRP to the shape factors of the RHS. With the formulations, the plastic moment capacity can be determined.