Engineering Guidance for Ramset AnkaScrews in Wall Tie Down Connections

Tie down connections for walls, especially critical bracing walls, are a complex system requiring an engineered solution. They often need to resist high loads despite being as close to 35mm from the edge of the slab (in the case of an external wall), and can fail through a number of different mechanisms if they are not designed and installed correctly.

Wind loads need to be transferred down to the earth through a series of connections to keep a house stable and free of damage. By combining Ramset AnkaScrews and Pryda washers, we supply a system solution that is simple for carpenters to install and makes it easy for builders to ensure the wall to slab connection does not become a weak link that undermines the rest of the build.

Anka Screws For Wall Tie Downs 1
RequirementsEngineered Solutions
Anchoring close to the
edge of the slab
Mechanical anchors such as a DynaBolt or TruBolt have a metal sleeve that expands when the bolt is torqued, expanding and biting into the concrete. This creates a strong connection, but the expansion force can cause the concrete to blow out if they are used too close to an edge. AnkaScrews do not expand and are suitable as close as 35mm to the edge of the slab.
Ease of installationChemical anchors are another option close to an edge, but their performance relies heavily on being installed correctly. They may perform well below their stated capacity if the holes are not cleaned properly, the holes are too wet, or the bolt is not inserted with the correct procedure. In contrast, installing an AnkaScrew is like screwing any other threaded fastener into a pilot hole, and therefore a great fit for carpenters.
Resist high uplift forces
on braced walls
High capacity bracing units can generate tie down loads of more than 20kN (2 tons) on a single anchor. Using a heavy-duty fastener like an AnkaScrew is essential.
Design, supply and
install as a system
It’s not just about the bolt. For the tie down connection to work, the load must be transferred from the wall (via the bottom plate) into the washer, up into the head of the bolt and then down into the slab. If any component of the system fails, the whole system fails.
ComplianceWe have worked closely with our sister company ramsetreid, who manufacture the AnkaScrew, to ensure that our technical guidance is fully up to date and compliant with the latest codes and standards.

Adam Dawson MIEAust, CPEng, NER, RPEQ (21909)
Technical Manager Pryda ANZ

Engineers Australia member No. 2766309