Two principal approaches to generating calculated seismic impacts, proposed in the practice of earthquake - resistant construction, were used and  refined: for the construction site and for the structure. There are special, emergency and extreme seismic loads that create an emergency situation - the occurrence of a mode of beats or resonant vibrations, as well as self-oscillations (acute resonance), leading to a violation of either the operational properties or the load-bearing capacity of the structure. Proposals are formulated for the revision of the Russian standards of earthquake-resistant construction, based on three-level impact for responsible and unique structures using the proposed refined approaches to generating calculated seismic impacts.

The article describing the mechanism of emergency through a sharp resonance phenomenon. Basic formulas and analytical expressions are included. It is suggested the possibility of using a sharp resonance phenomenon as the impact in the calculation of the buildings on the SSE level on seismic areas.

The work proposes the methods for determining special and emergency seismic loads and emergency calculation situations required in accordance with the current legislation. It is refined the previously proposed way of describing the structure movements with the help of nonlinear ordinary differential equations and the existence of stable limit cycles for them, leading to the appearance of stationary periodic solutions-self-oscillations. It is shown that the task of selecting a special (emergency) seismic action is reduced to the task of optimal speed, when the transition from one extreme position of the structure to another with external seismic action takes place in a minimum time. A proposal was made to apply special (emergency) harmonic seismic actions with a special frequency close to the natural oscillation frequency of the structure as a maximum design earthquake in seismic regions. Emergency seismic horizontal loads are allocated as loads that create an emergency situation. An algorithm for determining the special frequency of emergency seismic actions is presented. It is based on the comparison of the maximum displacements of structures arising from beats and self-oscillations.

The calculation of the stability of the equilibrium position required by the canceled and current norms of earthquake-resistant construction, and the calculation of the dynamic stability of various partial movements, the requirements for the necessity of which are absent both in the proposals for the norms of the new generation and in the current norms of earthquake-resistant construction, are the main ones in the calculation and design of structures taking into account their interaction with the base. Special and emergency seismic loads are identified that create an emergency situation − the occurrence of a mode of beating or resonant vibrations, as well as parametric resonance and nonlinear vibrations that occur after the loss of stability of the position of structures.