International Catalogue

Basic Knowledge of Fastening Technology
Basic Knowledge of Fastening Technology
Building materials
● Masonry
1 2
1. Solid sand-lime brick
2. Solid blocks, also known as brick or clinker brick
1
1. Horizontal coring brick and vertical perforated brick
are often described as perforated bricks or honeycomb
bricks.
2. Perforated sand-lime brick
1 2
1. Brick made of simple concrete, expanded clay,
2. Aircrete
Light concrete hollow blocks, e. g. of pumice or expanding
clay
2
Masonry shows a larger variety in contrast to the anchoring base concrete. The
width of different bricks that are joined together using different mortars into a single
masonry compound is very large.
The division of masonry can take place as per:
▪ The used brick (e.g. natural stone, bricks, lime stone or cellular concrete masonry).
▪ The constructive structure (e.g. single or double layer).
▪ The strength class and gross density of the brick.
▪ Generally, four groups of masonry blocks are differentiated:
▪ Solid blocks with dense structure are building materials that are very resistant
to compressive loads without cavities or with only a low percentage of hole surfaces
(up to max. 15%, e. g. as grip-hole). They are very well suited for anchoring
fixings.
▪ Perforated bricks with a compact structure (perforated and hollow
checker bricks) These are mostly manufactured from the same compressive
strength materials as the solid blocks but are provided with cavities. If higher
loads are introduced into these building materials, special fixings should be used
(e. g. injection anchorings), like those which bridge or fill out the cavities.
Solid blocks with porous structure usually have a very large number of pores
and low compressive strength. Therefore, special fixings should be used for
optimal fastening, e. g. fixings with long expansion zone and fixings that engage
with the material.
Perforated bricks with porous structure (light perforated bricks) have many
cavities and pores and thus usually low compressive strength. In this case, special
care is needed in selection and installation of the correct fixing. Suitable fixings
include those with a long expansion zone or injection anchors with a form locking
anchorage especially with light concrete hollow blocks, with cavities that can be
filled with polystyrene.
▸ Expert tip
▪ Before fixing in masonry find out about exactly, which stone (description, dimensions,
perforation, material, compressive strength) and which mortar (mortar category) is involved.
▪ For safety-relevant anchoring in unknown or old masonry, loading trials can be carried out
on site after consultation with the planner or the construction engineer.
▪ For fixings close to the edge it is of relevance whether a load lies on the masonry (e.g. roof
truss). The load prevents the stones from sliding out of the masonry compound.
▪ Even the so-called full bricks can have holes (e.g. MZ, KS). The holes are mostly larger gripholes
in the centre of the brick. (Up to max. 15% cavity proportion per brick)
▪ Always drill without hammering in ventilating and hollow bricks. Here special, well polished
drills with hard metal trimming are available.
▪ Plaster or other non load-bearing layers may not be added to the load-bearing base.
▪ The anchoring in the masonry joints must be avoided as far as possible due to the
inhomogeniety of joints. If the anchoring in a joint cannot be excluded (e.g. plaster on the
masonry), then it is recommended to reduce the load.
▪ For construction-related permissible systems, the anchoring in joints (straight or horizontal
joints) is regulated in the approvals.
▪ Lowering of fixings in the masonry makes sense only if high loads have to be anchored.
▪ Expansion fixing that punctually induces a high load in the base is mostly not suitable for
anchoring in the masonry (Exception: frame fixing for facade construction).
▪ Injection anchoring achieves the highest loads in masonry materials.
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