Torque-controlled anchor

A torque-controlled anchor is a post-installed expansion anchor that develops its grip as the nut or bolt is tightened to a specified torque, drawing a sleeve or wedge out so it expands against the wall of the pre-drilled hole. The two common types are the sleeve anchor (such as a Dynabolt), which expands a metal sleeve, and the wedge anchor (such as a Trubolt), which pulls a cone into expansion clips. Both rely on friction and clamping against the concrete or masonry, set by the install torque.

It is distinct from the other post-installed anchor families. A chemical anchor bonds a threaded rod into the hole with a resin and does not expand, so it suits cracked concrete, close edges, and the heaviest loads. A screw anchor cuts its own thread into the concrete and is removable. Torque-controlled expansion anchors are the medium-duty workhorse: bottom-plate tie-down, brackets, handrails, and light plant. For structural fixings (post bases, balustrade-to-slab, plant mounts) the engineer often steps up to a wedge or chemical anchor.

Torque is not optional. Under-tighten and the anchor never fully expands and can pull out; over-tighten and you can strip the hole or shear the anchor, so use the manufacturer’s torque setting, not “as tight as it’ll go”. Drill the hole to the right diameter and depth, clean it out, and set the anchor to spec. Structural anchor design sits under AS 5216. See sleeve anchor and wedge anchor.

Also known as: Torque-controlled expansion anchor, TCEA, expansion anchor.

Category: Fixings / Anchors.

Related

• Sleeve anchor
• Wedge anchor

See also

• Dynabolt sleeve anchor
• Trubolt wedge anchor
• Chemical anchor
• AS 5216 (post-installed fastenings)

References

• AS 5216:2021 Design of post-installed and cast-in fastenings in concrete, Standards Australia (verified 2026-05-11)
• Ramset: anchoring systems technical guide (verified 2026-05-11)

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Last updated: 2026-05-30. Verified: 2026-05-11. Quarterly review for currency.