Load-bearing performance of 3D printed steel fiber concrete circular arch structure under circumferential reinforcement

In order to enhance the mechanical properties of 3D-printed concrete arc arch structures, this paper uses the methods of adding steel fibre and configuring steel reinforcement to investigate the effect of circumferential reinforcement on the mechanical properties of 3D-printed steel fibre concrete arch structures. The appropriate steel fiber content was determined by mechanical property tests under different steel fiber contents. On this basis, two groups of 3D-printed concrete arc arch structures were designed. By applying a uniform load to the arch roof, the load-displacement curves, strain changes with load, cracking load, and ultimate load of the arch structures were measured, and their deformation and failure laws were analyzed. Considering the influence of symmetric and asymmetric loading, as well as the position of sectional reinforcement, on the arch structure, finite element calculations were carried out to further study its bearing performance. The results show that: (1) When the steel fiber content changes in the range of 0-3%, the compressive strength of 3D-printed concrete in X, Y, and Z directions first increases and then decreases, and the compressive strength in the X, Y, and Z directions corresponding to 2% steel fiber content is the highest; (2) The loading failure process of the two groups of arch structures is basically the same, and the ultimate bearing capacity of the arch structure with circumferential reinforcement is about 37.5% higher than that of the plain concrete arch structure; (3) The adopted finite element modeling method is relatively accurate, with the error between the simulation results and the test results less than 4%. The loading method and the position of section reinforcement have certain effects on the ultimate bearing capacity of the arch structure.