In Mechanics, you might have heard of statics and dynamics. Both fields deal with the study of forces. The former deals with objects at rest, while the latter deals with moving objects. When we refer to structural analysis, we have the same concept, but this usually refers to the type of load the structure may experience, which can be either static or dynamic.
Structural Statics
Static loads refer to loads that don't generate acceleration effects on the structure, such as dead loads and live loads.
Some loads cause these effects, such as the impact loading of vehicles and locomotives. For example, you might feel the bridge shake when a car crosses it. That is an example of an acceleration effect; however, in some cases, most express it only as a percentage to simplify the load analysis. In that way, those impact loads become static loads.
Structural Dynamics
When loads cause acceleration effects on the structure, these are dynamic loads. Wind gusts, earthquake loads, and blasts from weapons are all examples of such loads. When our analysis deals with these loadings, it is dynamic. This type has many forms, such as time history and response spectrum analysis.
Summary
Loads can either be static or dynamic.
Static loads do not generate acceleration effects on the structure (structural statics).
Dynamic loads cause acceleration effects on the building (structural dynamics).
