<p>This study investigates the seismic bearing capacity of shallow foundations by simultaneously accounting for the effects of eccentric loading and the inertial forces generated within both the soil and the superstructure. The analysis was performed using the limit analysis method, applying both the lower and upper bound theorems within a pseudo-static framework. Only the bearing capacity factor <i>N</i>_<i>γ</i>, associated with the unit weight of the soil, was considered. Soil inertia was represented through a horizontal seismic coefficient, whereas superstructure inertia was modeled as an equivalent horizontal load applied at the foundation level. The findings indicate that superstructure inertia produces a more pronounced reduction in bearing capacity, particularly under eccentric loading. Two superposition strategies were examined: a multiplicative approach, suitable for centered load cases, and a coupled numerical model, offering improved accuracy for eccentric configurations. The failure mechanism analysis further revealed that soil inertia tends to deepen the plasticized zones, while superstructure inertia induces localized overturning effects.</p>