A corbel (or bracket) is a short cantilever projecting from a column or wall, carrying a bearing reaction close to the face. Its shear span is so short that the load reaches the column almost directly, through a single inclined strut, and the cantilever never develops the internal moment arm that beam theory would assume. Codes treat it as a D-region and design it with a strut-and-tie model.
The model has three pieces. An inclined strut runs from the bearing plate down into the column. A horizontal tie across the top of the corbel — the primary tension steel — holds the top of that strut back into the column. The node under the bearing plate is where both meet, and it is usually the tightest check in the whole member, because the bearing area is small and the strut arrives at a steep angle.
Two details decide whether a real corbel behaves like the model. First, the horizontal load: bearings transmit friction, braking, shrinkage, and temperature movement, so the tie carries tension the vertical reaction alone does not explain — codes require a minimum horizontal force unless bearings genuinely prevent it. Second, anchorage: the primary tie must be fully developed beyond the outer edge of the bearing area, which in a member this short usually means welded cross-bars or hooks, not straight bar length.
- When it applies: a bracket whose shear span is short relative to its depth — the load goes to the column through one inclined strut
- The model: inclined strut + horizontal top tie + a node under the bearing plate
- What usually governs: the node under the bearing plate, and the anchorage of the top tie
- Horizontal load is not optional — codes require a minimum tensile force unless the bearing detail truly releases it
- Detailing: closed stirrups distributed over the upper part of the effective depth; the primary tie anchored beyond the bearing area
- In AStrutTie: the Corbel (bracket) template builds the strut-tie model, with the vertical and horizontal loads entered separately