Because of the constant threat of earthquakes in seismic hazardous areas, it is necessary to study the issues of seismic resistance of structures and development of methods of their design, taking into account the seismic factor. A significant share in the total volume of engineering structures permanent and built on canals and roads is occupied by artificial structures, such as aqueducts, small and medium bridges (overpasses). In this regard, the provision of seismic resistance of these structures is of practical interest. Buildings and structures located in seismic areas are affected by factors that cause the occurrence of seismic forces and changes in the working conditions of structures during earthquakes The article presents the results of comparison of calculations in the dynamic theory (by the method of spectral curves) and static seismic coefficient determination with the actual data on damage to structures in strong earthquakes. A formula for calculating the coefficient of seismicity is proposed.