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Ramset Trubolt+ Wedge Anchor

Ramset Trubolt+ is a torque-controlled wedge expansion anchor for the post-installed fixing of medium to heavy structural and non-structural elements to concrete substrates. The anchor is a stud-style wedge anchor, supplied in standard diameters of 6.5 mm to 24 mm and lengths from 50 mm to 320 mm, with the threaded stud projecting from the substrate to receive a fixture, washer and nut. Installation is by drilling a pilot hole sized to the anchor outside diameter, inserting the anchor through the fixture into the hole, and torquing the nut to expand the wedge against the surrounding concrete. The anchor develops capacity by torque-controlled mechanical expansion. Trubolt+ holds AEFAC technical approval for cracked and uncracked concrete with seismic approval per the AEFAC framework, and is supplied in zinc-plated carbon steel, mechanically-galvanised, and 316 stainless steel variants. TRSC specifies Trubolt+ for the post-installed fixing of structural steel base plates, heavy mechanical equipment, racking and shelving installations, and other applications where the load case is in the medium-to-heavy range and the through-bolt installation method is appropriate.

TRSC Specifier Commentary

Ramset Trubolt+ is TRSC's default torque-controlled wedge anchor specification for medium-to-heavy post-installed fixing in concrete. The product is selected over alternatives (Hilti HUS3 concrete screw, Hilti HSL3 sleeve anchor, Powers Spit-Lok drop-in) on three grounds: (1) load capacity — wedge anchors deliver the highest mechanical capacity per anchor in the standard mechanical-anchor categories, with the Trubolt+ M16 and M20 variants suitable for structural baseplate connections that previously required cast-in or through-bolted fixings; (2) AEFAC technical approval — the AEFAC (Australasian Engineered Fasteners and Anchors Council) approval framework provides Australian-specific design data and quality-assurance protocols, which simplifies design and certification under AS 3600 and AS 1170.4; (3) Australian-manufactured supply chain (Ramset is a long-established Australian anchor manufacturer with local technical support and product availability). The most common specification pitfalls TRSC encounters in the field are: (1) under-torquing — the wedge expansion mechanism develops design capacity only when the nut is torqued to the manufacturer-published installation torque; field installations that under-torque (typically because the contractor is using an impact wrench without torque calibration) produce anchors with a fraction of the design capacity; the contractor must use a calibrated torque wrench and verify the installation torque on the first 10% of installations as a witness hold point; (2) hole diameter — the pilot hole must be sized to the manufacturer's published diameter; oversized holes reduce wedge engagement and are a common cause of pull-out failure; the contractor's drill bit inventory must include the correct diameter for each anchor size; (3) edge distance and spacing — wedge anchors have larger minimum edge distance and inter-anchor spacing requirements than concrete screws, particularly in cracked concrete; congested anchor groups in narrow substrate conditions may require alternative specifications (concrete screws, injection adhesive anchors) to achieve the design capacity. TRSC anchor specifications include the product nomination, the anchor diameter and length, the embedment depth, the design load and seismic loads where applicable, the substrate edge distance and inter-anchor spacing requirements, and the installation torque.

Frequently Asked Questions

Specification questions about Ramset Trubolt+ Wedge Anchor

What is AEFAC approval and why does it matter?
AEFAC (Australasian Engineered Fasteners and Anchors Council) is the Australian framework for the technical approval and design of post-installed anchors. AEFAC approval provides Australian-specific design data, quality-assurance protocols and seismic provisions calibrated to AS 3600 and AS 1170.4, which simplifies design and Form 15 certification compared to anchors approved only under European (ETA) or US (ICC-ES) frameworks. TRSC specifications prefer AEFAC-approved anchors where available.
Why is correct installation torque so critical?
The wedge expansion mechanism develops design capacity only when the nut is torqued to the manufacturer-published installation torque. Under-torquing produces anchors with a fraction of the design capacity. Field installations using uncalibrated impact wrenches regularly fail pull-out QA testing because of under-torque. The contractor must use a calibrated torque wrench and verify the installation torque on the first 10% of installations as a witness hold point.
When does TRSC specify Trubolt+ over a concrete screw?
Trubolt+ is specified for medium-to-heavy load applications where wedge anchors deliver the required capacity per anchor and where the through-bolt installation method is appropriate. Typical applications are structural steel base plates, heavy mechanical equipment, and racking installations. Concrete screws (Hilti HUS3) are specified for lower loads, where flush-mount installation is required, or where the substrate edge distance constraints favour the smaller minimum edge distance of concrete screws.
Are wedge anchors suitable for cracked concrete?
Yes. Trubolt+ holds AEFAC approval for cracked and uncracked concrete with seismic provisions per the AEFAC framework. The design capacity in cracked concrete is reduced from the uncracked capacity per the AEFAC tables. In remediation contexts where the substrate is by definition not new concrete and may carry pre-existing cracking, the design must be against the cracked-concrete capacity unless the substrate has been investigated and confirmed crack-free in the anchor zone.
Sources & Further Reading