Experimental and numerical study of the flexural response of Ultra High Performance Concrete (UHPC) beams reinforced with GFRP

Abstract

This paper investigates the flexural behavior of Ultra High Performance Concrete (UHPC) beams reinforced with glass fiber-reinforced polymer (GFRP) bars. A series of four-point loadings tests were conducted on full-scale beams reinforced with Glass FRP (GFRP) bars. The GFRP-UHPC beams were designed as either under-reinforced or over-reinforced to examine the differences in their failure modes. Steel reinforced beams, serving as reference specimens, were also cast and tested. All the beams measured 185 mm in width, 250 mm in depth, and 2200 mm in length. The influence of reinforcement ratio, number of bars, and surface texture of GFRP bars on the flexural behavior was studied. The test results showed that changing the mode of failure from GFRP rupture to concrete crushing improved the ductility flexural capacity of the UHPC beams. It was also shown that the bending stiffnesses, flexural capacities, and strain responses of the UHPC beams were enhanced upon increasing the reinforcement ratio. The experimental data was compared with the ACI 440 and CAN/CSA S806 code provisions. It was found that the recent ACI440 ultimate moment equation provided acceptable results for the under-reinforced beams but was slightly unconservative for the over-reinforced beams. A nonlinear finite element (FE) model was also developed considering both material and geometric nonlinearities using ABAQUS. The developed FE model verified well with the experimental results and can be utilized to simulate different loading scenarios and sections of GFRP UHPC beams.