How do you make a cage end or corner connection with hairpin links?

In the case of a foundation beam end, or corner or straight section, there are different solutions for applying the reinforcement. The reinforcement must continue in those places so that the tensile forces are absorbed correctly.

Often a rebar cage end is prescribed by the constructor and mentioned on the drawing. Commonly used solutions are:

Rebar cage end with hairpin links (also called U-links).

• Advantage: Applicable everywhere.
• Disadvantage: Applying takes more time.

Prefab rebar cage with overlap at the end of the cage.

• Advantage: Easy and quick to apply.
• Disadvantage: Not applicable everywhere.

Rebar cage with hook end.

• Advantage: Easy and quick to apply.
• Disadvantage: Not applicable everywhere and at an angle or T-connection different layers of reinforcement come together.

Depending on the foundation, constructor or building situation, a certain solution is chosen.

The rebar cage end with hairpin links can be applied anywhere and offers the most freedom in application. The correct size of hairpin link is determined by the link dimensions of the reinforcement cage and the lapping length. More information about lapping length can be found here .

In the above example, the link sizes are 230mm wide and 430mm high. The reinforcement is Ø12mm. The theoretical dimensions of the hairpin links are a length of 815mm (lapping length at Ø12mm) and a height of 406mm (430 - 2 x 12mm). By taking the length slightly larger (for example 900 mm) there is some space for maneuver while placing the cages. When the height becomes 400mm, the hairpins slide easily into the rebar cage.

The same principle also applies when flank reinforcement is present. In this case the hairpin link is placed horizontally.

The assembly of a corner connection is easy to realize with hairpin links. You use 2 different heights of hairpin links for this, so that they easily slide into each other. The difference in height is 2 x the diameter of the reinforcement (rounded down). The width of the concrete beam is added to the length. This also applies to any flank reinforcement.

When making a T-connection, you also add the concrete beam width to the length. So lapping length + concrete beam width + some clearance (max 100mm) = length hairpin link.

Download as PDF :

Corner connection with hairpin links
End piece with hairpin links 
Coupling with lapping bars
Prefab rebar cage at concrete beam end
Reinforcing cage with hook link