Which point is considered where applied seismic forces traditionally act?

The center of mass is considered the point where applied seismic forces traditionally act because it represents the average location of the mass distribution of a structure. In the context of seismic analysis, when ground motion occurs, the forces generated by an earthquake are transmitted through the structure, and these forces tend to act at the center of mass.

The center of mass serves as the pivotal point around which the mass of the building is balanced, meaning that during the seismic event, the structure will respond to lateral forces as if all its mass were concentrated at this point. Engineers use this understanding to analyze and design buildings to ensure stability and to mitigate the effects of seismic forces.

The other options pertain to different concepts; for example, the center of gravity deals with the gravitational force, while the point of impact relates to where an external force hits a structure, and the equilibrium point is more about balanced forces rather than the specific location of applied seismic forces. Understanding these distinctions highlights the relevance of the center of mass in seismic design considerations.