Understanding force terms

By Ken Keberle

Static load: The basic load of the building, components, hanging components and snow load. A static load is one that accumulates and then stays put.

Dynamic load: A force exerted by a moving body on a resisting member, usually in a relatively short time interval. Dynamic loads include the wind, seismic forces, etc.

Hold down: How much force must be exerted to keep a building from lifting off its anchors.

Uplift: The upward force exerted by the wind on a building.

Shear force: The force that wants to move a building sideways. Generally, it is the accumulation of the wind pushing on the side of the tent or structure.

Shear resistance: The resisting force of the structure and ground that keeps pieces from failing parallel to it. The force that keeps a building from moving sideways.

Coefficient of friction: A measure of how “sticky” something is. This is a factor in determining shear resistance.

Wind load: The total force exerted on a structure by the wind. This includes the wind pushing down, lifting up, and pushing sideways on the structure.

Ken Keberle is a project manager at Prime Event Group in Tucson, Ariz. He can be reached at ken@primeeventgroup.com.