Products · Anchor cone
Anchor cones for post-tensioning.
The anchor cone is the cast trumpet behind the anchor head. It takes the full tendon force from the head and spreads it into the concrete at a bearing stress the concrete can carry.
What the anchor cone does
In a post-tensioned member every strand is gripped in the anchor head, and the head bears on the flange of the anchor cone. At lock-off the cone carries the whole tendon force, up to 400 t on a 12 AT 15 or 19 AT 13 anchorage, and turns that point load into an even bearing pressure on the concrete behind it.
The trumpet of the cone guides the strands from the duct to the head, and the HDPE sheathing duct connects to its tail. A spiral of reinforcement is cast around the cone to confine the concrete against the bursting force that builds up behind every anchorage.
Choosing the cone
The cone is set by the tendon, not chosen separately. Each AT model has one cone size (dimension A on the TYROS data sheet), one pocket depth (D), a minimum edge distance (B) and a minimum spacing between anchorages (C). The designer checks those against the end block or bulkhead before the reinforcement is detailed.
Cones are fixed to the formwork at the bulkhead with the duct attached and grout inlets in place before the concrete is poured. TYROS supplies the cone with its matching spiral, anchor head, wedges and duct as one kit per anchorage.
Need it installed and stressed as well? TYROS crews do that too: post-tensioning stressing services.
Anchor cone sizes by AT model (TYROS data sheet, mm)
| Model | Cone A × A | Pocket depth D | Min. edge B | Spacing C | Duct ID |
|---|---|---|---|---|---|
| 12 AT 15 | 245 × 245 | 62 | 200 | 300 | 90 |
| 19 AT 13 | 245 × 245 | 62 | 198 | 325 | 90 |
| 12 AT 13 | 207 × 207 | 52 | 148 | 260 | 75 |
| 4 AT 13 | 145 × 145 | 45 | 120 | 220 | 51 |
| 7 AT 13 | 145 × 145 | 45 | 120 | 220 | 51 |
Anchor cone questions.
Asked by designers and contractors before ordering.
What size anchor cone do I need for a 19-strand tendon?
A 19 AT 13 anchorage (nineteen 12.7 mm strands) uses the 245 × 245 mm cone, the same cone as 12 AT 15. Both carry 400 t UTS.
What is the difference between an anchor cone and an anchor head?
The anchor head is the drilled steel disc that holds each strand with its wedges. The anchor cone sits behind it in the concrete and spreads the head's load into the member.
What edge distance and spacing do anchor cones need?
From 120 mm edge and 220 mm spacing for 4 and 7 AT 13, up to 200 mm edge and 300 to 325 mm spacing for 12 AT 15 and 19 AT 13. The full table is on this page and on the specifications page.
Is the spiral supplied with the cone?
Yes. Every TYROS anchorage kit includes the cone, its spiral reinforcement, the anchor head, wedges and HDPE duct.
The rest of the AT anchorage
- Wedges for post-tensioning
- Anchor head for post-tensioning
- Spiral reinforcement 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.