Experimental investigation and numerical analysis of RC beams shear strengthened with FRP/ECC composite layer

Five Reinforced Concrete (RC) beams strengthened with Basalt Fiber Reinforced Polymer (BFRP) grid in conjunction with Engineered Cementitious Composite (ECC) were tested along with one conventional RC beam for reference to investigate their performance improvement, particularly in shear capacity, due to strengthening. The test results highlighted that the failure modes of the tested beams were dominated with shear-compression failure in the shear/bending moment regions and concrete crushing in the compression part of the pure bending zone. A good bonding performance between the BFRP-ECC composite and concrete substrate was exhibited during the testing process, which can effectively suppress the propagation of diagonal cracks in the shear/bending moment regions. The shear capacity of strengthened RC beams was greatly improved with the increase of BFRP grid reinforcement ratio. Moreover, the reinforcement effect of this strengthening technique was much more effective with the increase of shear-span ratio of the tested RC beams. Furthermore, finite element analyses based on ABAQUS/Standard software were conducted to provide analytical estimations of the shear capacity of the strengthened RC beams. The analytical results revealed that the predicted values agree very well with the test data, which can effectively predict the shear capacity of RC beams strengthened with BFRP-ECC composite.