FRP-UHTCC复合层抗剪增强钢筋混凝土梁受力性能试验研究

Six reinforced concrete (RC) beams shear-strengthened with FRP grid reinforced-ultra high toughness cementitious composite (UHTCC) were tested to investigate the shear performance. The reinforcement ratio of FRP grid and the shear-span of the beams were selected as the test parameters to investigate their effects on the mechanical performance of FRP-UHTCC-strengthened RC beams. A shear capacity formula of FRP-UHTCC-strengthened RC beams was proposed based on the test results. The experimental results show that the failure modes of the tested RC beams are shear compression failure in the shear/flexure region and crushing of concrete in the compression zone. Good bonding performance between the FRP-UHTCC composite and the concrete substrate is observed during the test. The propagation of diagonal cracks in the shear/flexure regions is effectively suppressed. The shear capacity of strengthened RC beams is greatly improved with the increase of reinforcement ratio of FRP grid. The reinforcement effect of this strengthening technique is improved with the increase of the shear-span ratio. The maximum increase in shear capacity reached 61% comparing to the non-strengthened reference beam. The proposed formula is validated through the comparisons between the prediction and the measured shear capacity of RC beams shear-strengthened with FRP-UHTCC composite.