What is a shear dowel?
A shear dowel is a smooth, often galvanised steel bar embedded in a concrete structure to transfer shear forces between two elements, while allowing both parts to move independently in the longitudinal direction. The dowel makes an expansion joint possible without creating a step or height difference between the elements.
How does a shear dowel work?
The bar sits half-embedded in one element and projects through a sleeve into the other. As a result:
- Vertical loads (shear forces) are transferred from one part to the other
- Horizontal movement remains possible due to shrinkage, temperature or settlement
- No friction thanks to the smooth surface and sliding sleeve
Both slab fields, or wall and floor, stay at the same level but work structurally independent of each other.
Application
Shear dowels are widely used in:
- Industrial and poured floors — at expansion joints to prevent steps under traffic load
- Parking decks — where tyres cross the joints
- Warehouses — to avoid cracking under forklifts
- Precast concrete elements — connecting wall and floor units
- Bridges and viaducts — for expansion and contraction
Types of shear dowel
| Type | Shape | Application |
|---|---|---|
| Round dowel | Cylindrical | Standard floor expansion joints |
| Square dowel | Square with plastic sleeve | Heavy-duty industrial floors |
| Plate dowel (Diamond Dowel) | Flat diamond shape | Poured floors, easy to install |
Key considerations
- Install horizontally — a tilted dowel does not work
- Lubricate or sleeve one side — otherwise unwanted bond develops
- Centre-to-centre spacing — typically 300–500 mm to design
- Sufficient edge distance — to prevent cracking
Related terms
- Expansion joint
- Concrete
- Plate dowel
- Shrinkage joint
- Reinforcement
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