The effect of CHC joints on the mechanical performance of prefabricated subway stations

The mechanical behaviour of novel CHC joints in prefabricated subway stations (PSSs) is not yet fully understood. The impact of CHC joints on the mechanical performance of large-span column-free PSSs was thus investigated in this work. Experiments and numerical simulations were employed to comparatively analyse structural characteristics under different joint types and varying service load conditions. The internal force regulation and force transfer mechanisms of the CHC joint were assessed. The results show that the CHC joint plays a role in adjusting the bending moment distribution of the structure, which helps to reduce the thickness of components. Considering the CHC joint, the central deflection of the prefabricated structure’s top plate was 14% larger than that of a cast-in-place structure, and failure of the filling material increased this value to 18%. During bending, the CHC joint transfers pressure through the stabilised C-shaped steel on the compression side. The contribution of filling materials to the bending resistance of the CHC joint is approximately 8%. The shear resistance mechanism of the CHC joint primarily relies on frictional shear. The findings of this work provide valuable references for the structural design of PSSs.