An example of a static load is the weight of a roof on the posts of a house. Static loads are stationary forces or weights that do not change in position or magnitude. This is in contrast to dynamic loads, which do change position or magnitude over time.
To illustrate the difference between a static load and a dynamic load, imagine a truck in the middle of a bridge. While the truck is parked, it exerts a stationary load upon the bridge via its weight. Once it begins to drive along the bridge, it becomes a dynamic load. Structures designed to handle static loads, such as the walls of a building, are not necessarily up to handling dynamic loads placed upon them; for example, the World Trade Center pancaked under the force of the dynamic loads generated by the floors it had been holding up as static loads for decades.