Energy dissipation mechanism of base plate yielding systems is investigated based on results of shaking table tests using a half scale steel frame with three stories. Hysteresis damping capacity of yielding base plates is verified. And effects of vertical inertia force to the energy dissipation mechanism which include impact effects are clarified. The energy dissipation of the system corresponding to the maximum momentary input energy is expressed using the maximum rigid rotational anele. The maximum response displacements are predicted considering the energy balance condition of the system.
