Products · Spiral reinforcement
Spiral reinforcement for anchorages.
Behind every anchorage the concrete is pushed apart by a bursting force. A helical spiral of reinforcing bar, cast around the anchor cone, confines that concrete so it can carry the load.
Why the spiral matters
The anchor cone concentrates up to 400 t into a small area of concrete. Just behind it, that compression spreads out and creates tension across the member, which can split the concrete if it is not confined. The spiral wraps that zone and holds it together.
Its size is part of the anchorage design, not a site choice. The TYROS data sheet gives the spiral diameter (F), length (G), bar diameter (H), number of turns (N) and pitch (J) for each model, and the spiral is supplied with the cone.
Need it installed and stressed as well? TYROS crews do that too: post-tensioning stressing services.
Spiral reinforcement by AT model (TYROS data sheet)
| Model | Diameter F (mm) | Length G (mm) | Bar H (mm) | Turns N | Pitch J (mm) |
|---|---|---|---|---|---|
| 12 AT 15 | 250 | 540 | 16 | 9 | 60 |
| 19 AT 13 | 250 | 540 | 16 | 9 | 60 |
| 12 AT 13 | 190 | 480 | 16 | 8 | 60 |
| 4 AT 13 | 150 | 240 | 16 | 6 | 40 |
| 7 AT 13 | 150 | 240 | 16 | 6 | 40 |
Spiral reinforcement questions.
Asked by designers and contractors before ordering.
What is anti-burst reinforcement in post-tensioning?
Reinforcement placed behind the anchorage to resist the bursting (splitting) force caused by the concentrated tendon load. The spiral around the anchor cone is the main part of it.
Is the spiral supplied with TYROS anchorages?
Yes. Each anchorage kit includes its spiral, sized to the cone per the data sheet.
Does TYROS help with the anti-burst detailing?
Yes. The TYROS technical team provides anchorage specifications, anti-burst reinforcement details and stressing methodology to the contractor.
The rest of the AT anchorage
- Anchor cone for post-tensioning
- Wedges for post-tensioning
- Anchor head for post-tensioning
- HDPE sheathing duct for post-tensioning
See all five models together on the AT anchorage system page.
Send us the tendon schedule. We'll send back the anchorage.
Anchorage specifications, anti-burst reinforcement details and the stressing methodology — for every contractor, on every job.
Need the tendons stressed too? See our post-tensioning stressing services.