Numerical Investigation on Shear Behavior of Reinforced Concrete Beam with 3D Printed Concrete Permanent Formwork (2024-12)¶

The mechanical performance of composite structure with 3D printed concrete (3DPC) permanent formwork differs significantly from that of traditional concrete structures since 3DPC exhibits obvious spatial anisotropy owing to the influence of the printing process. The shear failure of concrete structure is brittle, and special attention on this issue should be paid to the structural design. However, few research reported the shear performance of composite beam with 3DPC permanent formwork. To figure out the shear performance of a composite beam with 3DPC permanent formwork, this study established a fine finite element model based on the shear tests of composite beams and microstructure information of printed concrete, and discussed the numerical simulation accuracy based on the load–displacement response and failure mode of the tested composite beam. The factors influencing the shear performance of the composite beam were analysed according to parameters, such as shear-span ratio, concrete strength and printed strip size. The results show that the shear performance, crack morphology, and failure mode of the composite beams can be simulated with high accuracy. The parameter analyses show that the shear bearing capacity of composite beams was approximately linearly correlated with the compressive strengths of the cast and printed concrete, and the strength of the internal cast concrete affected the bearing capacity more sensitively than that of the printed permanent formwork. The ultimate shear bearing capacity of the composite beam gradually decreased with increasing shear-span ratio. The thickness and width of the printed strip had little effect on the shear bearing capacity, but had a significant effect on the stress concentration of the beam web. A smaller strip thickness and width would cause an intenser strain concentration owing to the stiffness discontinuity, leading to a higher risk of web shear and interface bonding failure.