What does 'plastic anchors for redundant non-structural systems in concrete and masonry' mean?
- Read time: 1 minutes
- Date: 02 Aug 2024
- Rainscreen & Façades
Within the ETA for nylon frame fixings is a statement: 'plastic anchors for redundant non-structural systems'.
So the question arises: can they be used to fasten the support system of a rear-ventilated rainscreen façade?
Anchor bolts are used to connect both structural and non-structural elements to a structure - for example:
A connection between structural elements can be represented by a steel column attached to a reinforced concrete foundation (nylon frame fixings aren't suitable for such applications)
A common case of a non-structural element attached to a structural one is between a façade system and a structural backing wall
In the recognised standard CEN TR 17079:2018, examples are provided, and references made to 'statically indeterminate non-structural lightweight systems' - meaning the stability of the fixture is not dependent on every other anchor supporting it: failure of one would not lead to the collapse of the entire element.
The assumption is that under extreme conditions, such as a large crack width causing excessive slip or fastener failure, the following are considered:
systems are fixed with a minimum of 3 fixing points
only fasteners of the same type, size, and length are used
the attached façade support system is sufficiently stiff to transfer the load at any fixing point to adjacent fixing points, without significantly impairing the performance characteristics of the system
For a façade rail and bracket support system to comply with the definition above, it needs at least 3 brackets per rail, and the rail needs to be sufficiently rigid to transfer the load to the next bracket.
Any designs using our system will meet these criteria.
So, nylon frame fixings are suitable for fixing brackets to concrete and masonry substrates as the façade support system.
