International Catalogue

Basic Knowledge of Fastening Technology
Basic Knowledge of Fastening Technology
Loads
▸ Expert tip
▪ The clearance holes of the attached item are specified for the respective anchor
size in the approvals and in the manufacturer’s specifications.
▪ For a stand-off installation with a cross load V of the anchor, an additional bending
moment occurs which is mostly standard.
▪ The attached item must lie flat on the base and may be lined with a compressionproof
levelling course of max. 3 mm or with half the diameter of the anchor. Otherwise,
the anchoring must be assessed as a stand-off installation with a lever arm.
▪ The attached item must lie on the entire length of the clearance hole (= thickness of
the attached item) at the anchor/threaded bolt. Otherwise, the anchoring must be
assessed as a stand-off installation with a lever arm.
▪ Comply with the maximum fixing height t fix in the manufacturer’s specifications.
This dimension, also specified as the useful length, consists of:
t fix = thickness of the attached item + non load-bearing layers up to the load-bearing
base.
▪ Many of the officially approved anchors must be tightened with a prescribed torque.
A calibrated torque key must be used for this. The torque ensures the necessary
preload force as well as the correct installation of the anchor. For chemical anchors,
the prescribed hardening time must be allowed before a tightening torque or
service load may be applied.
▪ Anchors must be mounted as units delivered in series. The exchange or removal of
parts is not permissible.
For the selection of an anchor, it is necessary to know the load on the total construction
and the resulting anchor cutting forces for every individual anchor.
The cutting forces can be distinguished according to:
▪ Dimension
▪ Direction
▪ Type of load
▪ Pickup point
There are various types of loads.
In the approvals, characteristic failure loads are generally given. In documents with
the manufacturer’s specifications, anchors with approvals, so-called permissible
loads are given. For anchors without approval, a manufacturer’s recommendation
is given as “recommended load”.
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