Abstract: Based on ABAQUS/Explicit, the numerical models of bolted-welded hybrid and all-welded planar frame substructures of concrete-filled steel tubular (CFST) columns and H-shaped steel beams are established. The falling hammer was utilized in the finite element model to simulate the falling fragments from the superstructure caused by accidental load damage. Falling-debris impacts were applied to different locations along the span of the steel beams to explore the effect of locations on impact resistance by comparing failure mechanism and energy dissipation capacity. Results show that: under the mid-span impacts, the joint position of the substructure is mainly characterized by tension-bending failure, tension of the upper flange, inward curl of the lower flange under pressure, and vertical development of cracks; while under the impacts at the beam end, it mainly shows shear failure, and the joint position shows oblique development cracks around the web-flange junction of the steel beam. The average impact force generated by the mid-span impact is smaller than that by the beam-end impact. The deflection recovery ability after the mid-span impact is about 8%~12% higher than that of after the beam-end impact. By analyzing the load resistance mechanism, the resistance contribution of mid-span impacts is dominated by bending effects, reaching 90%, while that of the beam-end impacts is only about 65%. The total energy dissipation is higher under mid-span impacts due to the favorable bending stiffness, and the steel beam, as the main energy dissipating component, has an advantage over the impact energy dissipation at the end of the beam. Compared with the impact effect on 1/3 and 1/4 beam-span positions, the closer the impact load is to the middle of the span, the maximum vertical displacement of the substructure increases, the catenary stage is longer, the energy dissipation capacity is enhanced, and the impact resistance is better.