Mechanical Anchors
Expansion, Wedge, Sleeve, Drop-In & Undercut Anchors
Mechanical anchors generate holding capacity through mechanical interlock between the anchor and the substrate. Expansion anchors (wedge and sleeve types) work by expanding against the bore wall when tightened, creating friction and interlock that resists pull-out. Undercut anchors use a shaped bore to create a positive mechanical key that does not rely on sustained friction.
Mechanical anchors are widely used in commercial construction for medium-duty connections: steel-to-concrete brackets, base plates, equipment mounting, and secondary structural elements. They offer immediate loading (no cure time), are less sensitive to hole cleaning than chemical anchors, and provide visual confirmation of proper expansion through torque application.
While mechanical anchors are generally less testing-intensive than chemical anchors, proof load testing remains essential for safety-critical installations. Expansion anchors can under-perform in cracked concrete, near edges, or in low-strength substrates where the expansion force exceeds the concrete tensile capacity. Undercut anchors, while more reliable in cracked concrete, require precise bore geometry that must be verified during installation.
ATA conducts proof load testing for mechanical anchors in safety-critical applications, structural connections, and installations where substrate quality is uncertain. Ultimate load testing is required when the mechanical anchor is installed in a substrate type or condition not covered by the manufacturer's ETA.
Design of post-installed and cast-in fastenings in concrete
Code of practice for post-installed anchors
Australian site testing guidance
European assessment for mechanical anchors
Book proof load or ultimate load testing for mechanical anchors.
Mechanical Anchors tested by ATA
Hilti HST3
The Hilti HST3 is a heavy-duty wedge expansion anchor designed for high-load structural connections in concrete. It uses a torque-controlled expansion mechanism with an optimised expansion sleeve that provides consistent clamping force across a range of concrete strengths and conditions.
Ramset DynaBolt Plus
The Ramset DynaBolt Plus is a sleeve expansion anchor designed for medium-duty anchoring in concrete, brick, and block masonry. It uses a sleeve-and-cone expansion mechanism activated by tightening the bolt, which draws the cone into the sleeve and expands it against the bore wall. The DynaBolt is one of the most widely used general-purpose anchors in Australian commercial construction.
Fischer FAZ II
The Fischer FAZ II is a through-bolt expansion anchor designed for heavy-duty structural connections in concrete. It uses a torque-controlled expansion mechanism with a precision-engineered expansion cone that provides consistent and high clamping force across a range of concrete grades.
Book mechanical anchors testing with ATA
Send your anchor schedule, specification, or project details. ATA will scope the testing programme, define the proof loads, and mobilise to site.