Definition
A grade beam is a reinforced concrete beam that rests on the ground surface and transmits loads from columns or piers to the soil. Unlike continuous footings, grade beams span between piers and do not transfer load through bearing on the soil beneath them-they act as horizontal structural members connecting vertical supports. Grade beams are commonly used on slopes, expansive soils, or when piers are required instead of traditional footings.
Formula
For typical grade beams, depth is approximately 1/12 of the span length. A 12-foot span requires at least a 12-inch deep beam. Width is typically equal to the column width or pier diameter. Reinforcement varies based on loading conditions-consult structural engineering requirements for your specific application.
Example
Grade Beam Example
On a sloped site with drilled piers, grade beams connect the piers at finished grade elevation. For piers spaced 10 feet apart, a 10x12 inch grade beam with #5 rebar top and bottom is typical. The beam transfers column loads to the piers while providing a level base for the above-ground structure.