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GENERAL REQUIREMENTS FOR FASTENINGSSORMAT Technical manual 07/2008
1 GENERALREQUIREMENTSFORFASTENINGS1.1BASEMATERIAL
1.2USAGETARGET
1.3LOADSANDRESISTANCES
1.4INSTALLATION
1.5FASTENINGSYSTEMSAND
MODEOFACTIONS
1.6OTHERASPECTS
2 PRODUCTBASEDINFORMATION2.1METALANCHORS
2.2CHEMICALANCHORS
2.3PLASTICANCHORS
3 TRUSTFIX3.1TRUSTFIXGENERALINFORMATION
3.2TRUSTFIXTRAININGGUIDE
4 TECHNICALLITERATURE4.1ETAG001
ANNEXC
SORMAT Technical manual 07/2008
TAble 1.1 SELECTIONOFTHEANCHOR
before you choose an anchoring
method and type of anchor you
have to find out first the properties
of the base material and installa-
tion and service conditions. Table 1
shows the most important aspects
affecting the anchor selection. The
base material has to be studied
carefully, e.g. material, quality and
shape. The usage target determin-
est e.g. the type of construction,
reinforcements, location and ser-
vice temperature. loads have to be
studied carefully. Also the installa-
tion method restricts the mode of
selection.
Of course there are lots of other
aspects which have to be consid-
ered before the selection and the
most important of these are safety,
service life, fire resistance, econo-
my and availability.
SELECTIONOFTHEANCHOR
BASEMATERIAL
CONSTRUCTIONMATERIAL• concrete (compress
or tensile zone)• masonry work• light constructionSHAPEOFTHECONSTRUCTION
CONSTRUCTION• bearing• non- bearingLOCATION• indoor (dry, humid, aggressive)• outdoorTEMPERATURE
VALUECharacter• regular• variableDIRECTION• direct• shear and
inclined pull
SafetyService lifeFire resistanteconomyAvailability
USAGETARGET LOADS INSTALLATIONMETHOD
OTHERASPECTS
1GENERALREQUIREMENTSFORFASTENINGS
THROUGHINSTALLATION
DISTANCEINSTALLATION
PREINSTALLATION
SORMAT Technical manual 07/2008
1.1BASEMATERIAL
1.1.1CONCRETE
1.1.1.1MaterialDescription
Concrete is a composite building
material made from a combination
of aggregate and cement binder.
The most common form of con-
crete consists of Portland cement,
mineral aggregates (generally
gravel and sand), and water. Con-
crete is used more than any other
man-made material on the planet.
1.1.1.2 History
The Assyrians and babylonians
used clay as cement in their con-
cretes. The egyptians used lime
and gypsum cement. In the Ro-
man empire, concrete made from
Quicklime, pozzolanic ash / pozzo-
lana and an aggregate made from
pumice was very similar to modern
Portland cement concrete. In 1756,
the british engineer John Smeaton
pioneered the use of Portland ce-
ment in concrete, using pebbles
and powdered brick as aggregate.
In the modern day, the use of re-
cycled materials, such as concrete
ingredients, is gaining popularity
because of increasingly strin-
gent environmental legislation.
The most conspicuous of these is
pulverized fuel ash, recycled from
the fly ash by-products of coal
power plants. This has a significant
impact on reducing the amount of
quarrying and the landfill space
required.
1.1.1.3 Composition
The composition of concrete is
determined initially during mixing
and finally during the placing of
fresh concrete.
1.1.1.3.1 Cement
Portland cement is the most com-
mon type of cement in general
usage, as it is a basic ingredient of
concrete, mortar and plaster. An
english engineer named Joseph
Aspdin patented Portland cement
in 1824, which was named after
the limestone cliffs on the Isle of
Portland in england because of the
similarity of its colour to the stone
quarried from Portland. It consists
of a mixture of oxides of calcium,
silicon and aluminium. Portland
cement and similar materials
are made by heating limestone
(a source of calcium) with clay
and grinding this product (called
clinker) with a source of sulphate
(most commonly gypsum). The
resulting powder, when mixed
with water, will become a hydrated
solid over time.
1.1.1.3.2 Water
Water suitable for human or
animal consumption can be used
in manufacturing concrete. The
ratio of water-to-cement is the key
factor determing the strength of
concrete. It is also a key factor in
the viscosity of wet concrete, which
directly affects its workability
during placement. A lower water-
to-cement ratio will yield a con-
crete which is stronger, but more
difficult to work. A higher water-
to-cement ratio yields a type of
concrete which is easier to work,
but it will have a lower strength.
1.1.1.3.3 Aggregates
The water and cement paste
hardens and develops strength
over time. In order to ensure an
economical and practical solution,
both fine and coarse aggregates are
utilised to make up the bulk of the
concrete mixture (Picture 1.1). Sand
and crushed stone are mainly used
for this purpose. Decorative stones,
such as quartzite or small river
stones, are sometimes added to the
surface for a decorative “exposed
aggregate” finish, popular among
landscape designers. Recycled
crushed glass can also be added
in the production of concrete for
an aesthetic effect (such as in the
construction of walkways).
1.1.1.3.4 Admixtures
Admixtures are organic or non-
organic materials in the form of
solids or fluids that are added
to the concrete to give it certain
PICTURE1.1Coarseandfineaggregates
1.1 bASe MATeRIAl
BACKTOMAINMENU
SORMAT Technical manual 07/2008
characteristics, following the lead
of the ancient Romans. In normal
use, the admixtures make up less
than 5 % of the cement weight,
which are added to the concrete at
the time of batching/mixing. The
most common types of admixtures
are:
• Accelerators speed up the
hydration (“hardening”) of the
concrete.
• Retarders slow the hydration of
concrete.
• Air-entrainers add and distribute
tiny air bubbles in the concrete,
which will reduce damage during
freeze-thaw cycles.
Plasticizers can be used to •
increase the “workability” of con-
crete, allowing it be placed more
easily, with less compactive effort.
• Superplasticisers allow a prop-
erly designed concrete to flow
in place even around congested
reinforcing bars. Alternatively,
they can be used to reduce the
water content of concrete (water
reducers) while maintaining
workability. This improves its
strength and durability
• Pigments change the colour of
concrete for aesthetic purposes
1.1.1.3.5Additions
Additions are very fine inorganic
materials that usually have poz-
zolanic or latent-hydraulic prop-
erties, which are added to the
concrete mixer to improve the
properties of concrete. The term
is not used when the materials are
added at the factory as constitu-
ents of blended cements.
• Fly ash: A by-product of coal-
fired electric generating plants
fly ash is used to partially replace
Portland cement by up to 40 %
in weight. experiments have
determined that the use of ash up
to 95 % can produce a structur-
ally sound concrete; however it
is only useful under limited load
pressures.
• Ground granulated blast fur-
nace slag: A by-product of steel
making, it is used to partially
replace Portland cement (by up
to 80% by weight). larger slag is
sometimes used as an aggregate
as well.
• Silica fume: A by-product of the
production of silicon and fer-
rosilicon alloys. Silica fume is
a very reactive pozzolan that is
used to increase strength and
durability of concrete.
1.1.1.4 Characteristics
During hydration and hardening,
concrete needs to develop certain
physical and chemical proper-
ties. Among others, mechanical
strength, low permeability to mois-
ture, and chemical and volumetric
stability are all necessary. Table
1.2 shows the average densities for
different concrete types.
1.1.1.4.1Strength
Concrete has relatively high com-
pressive strength, but significantly
lower tensile strength (varies 7–13 %,
average 10 % of the compressive
strength). As a result, concrete
always fails from tensile stress -
even when loaded in compression.
The practical implication of this is
that concrete elements subjected to
tensile stress must be reinforced.
Concrete is most often constructed
with the addition of steel or fibre re-
inforcement. The reinforcement can
be by bars (rebar), mesh, or fibres,
producing reinforced concrete.
Concrete can also be pre-stressed
(reducing tensile stress) using steel
cables, allowing for beams or slabs
with a longer span than is practi-
cal with reinforced concrete alone.
The ultimate strength of concrete
is primarily influenced by the
water-cement ratio w/c or water-
cementatious materials ratio (w/
cm) and the mixing and placement
methods employed. Concrete with
a lower water-cement ratio makes
a stronger type of concrete than a
higher ratio. The total quantity of
cementatious materials can affect
strength, such as shrinkage cracks,
which develop in the cement paste
while curing, can weaken the final
product. In high-strength concrete,
the strength of the aggregate can be
a limiting factor. In concrete with
a high water/cement ratio, the
shape of the aggregate may affect
the strength: if a weak cement-
aggregate bond zone develops,
cracks will develop much more
easily along smooth aggregate
TYPEWEIGHTKG/m³
Plain concrete, with natural stone aggregate 2 300
Plain concrete, with natural broken brick aggregate 2 000
Reinforced concrete, with dense aggregate 2 400
lightweight aerated concrete 400 - 650
lightweight aggregate structural grade concrete 1 800
Steelshot aggregate concrete 5 300
TAble 1.2 CONCRETEDENSITIES
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
than along rough aggregate.
experimentation with various
mix designs is generally done by
specifying desired “workability”
as defined by a given slump and
a required 28-day compressive
strength. The characteristics of
the coarse and fine aggregates
determine the water demand of
the mix in order to achieve the
desired workability. The 28-day
compressive strength is obtained
by determing the correct amount
of cement to achieve the required
water-to-cement ratio. Only with a
very high-strength concrete does
the strength and shape of the
coarse aggregate become critical
in determining ultimate compres-
sive strength.
The internal forces in certain
structures, such as arches and
vaults, are predominantly com-
pressive forces, and, therefore,
concrete is the preferred construc-
tion material for such structures.
It is possible to reduce material
usage with high-strength con-
crete (60 - 100 MPa). As a result of
developing high-strength concrete
it was estimated that, for exam-
ple, doubling the strength of the
column will reduce relative costs
approximately 25 %. Also from the
environmental point of view, the
use of high-strength concrete is
beneficial.
The utilization of ultra-strength
concrete (150-250 MPa) is becom-
ing more and more popular in
special structures. Different fibres
are used e.g. steel, glass, carbon
or plastic, to improve the tensile
strength of the structure.
1.1.1.4.2 Consistence
Consistence is the ability of a fresh
(plastic) concrete mix to fill the
form /mould properly with the
desired work (vibration) without re-
ducing the quality of the concrete.
Consistence depends on water
content, chemical admixtures,
aggregate (shape and size distribu-
tion), cementatious content and
age (level of hydration). Raising the
water content or adding chemical
admixtures will increase concrete
workability. excessive water will
lead to increased bleeding (sur-
face water) and/or segregation
of aggregates (when the cement
and aggregates start to separate),
with the resulting concrete hav-
ing a reduced quality. The use of
an aggregate with an undesirable
graduation can result in a very
harsh mix design with a very low
slump, which cannot be readily
made more workable by the ad-
dition of reasonable amounts of
water.
1.1.1.4.3 Curing
because the cement requires time
to fully hydrate before it acquires
strength and hardness, concrete
must be cured once it has been
placed. Curing is the process of
exposing concrete to a specific
environmental condition, until
hydration is relatively complete.
Good curing is typically considered
to require a moist environment
that promotes hydration, since
increased hydration lowers per-
meability and increases strength,
resulting in a higher quality mate-
rial. Allowing the concrete surface
CONCRETE GRADE fck,cyl(N/mm²) fck,cube(N/mm²)
NORMAL
C8/10 8 10
C12/15 12 15
C16/20 16 20
C20/25 20 25
C25/30 25 30
C28/35 28 35
C30/37 30 37
C32/40 32 40
C35/45 35 45
C40/50 40 50
C45/55 45 55HIGHSTR
ENGTH
C50/60 50 60
C55/67 55 67
C57/70 57 70
C60/75 60 75
C65/80 65 80
C70/85 70 85
C75/90 75 90
C80/95 80 95
C85/100 85 100
C90/105 90 105
C100/115 100 115
TAble 1.3 THEMOSTCOMMONCONCRETEGRADES
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
to dry out excessively can result in
tensile stress, which the still-hy-
drating interior cannot withstand,
causing the concrete to crack.
Also, the amount of heat gener-
ated by the chemical process of
hydration can be problematic for
very large placements. Allowing
the concrete to freeze in cold cli-
mates before the curing is com-
plete will interrupt the hydration
process, reducing the concrete
strength and leading to scaling
and other damage or failure. The
effects of curing are primarily a
function of specimen geometry,
the permeability of the concrete,
curing length and curing history.
Picture 1.2 shows a series of
pictures of different stages of the
curing process. The upper left
corner shows cement particles in
water. The right top corner shows
the situation after a couple of min-
utes of adding water. The bottom
left corner shows the situation
after a couple of hours with hydra-
tion products expanding into the
water chamber. The bottom right
corner shows the situation after
couple of days.
1.1.1.4.4 Expansionandshrinkage
Concrete has a very low coefficient
of thermal expansion. However if
no provision is made for expansion,
very large forces can be created,
causing cracks in parts of the
structure not capable of withstand-
ing the force or the repeated cycles
of expansion and contraction.
As concrete matures, it continues
to shrink, due to the ongoing reac-
tion taking place in the material.
A brickwork of made of clay tends
to expand for some time after the
manufacture of the bricks, and the
relative shrinkage and expansion
of concrete and brickwork require
careful accommodation when the
two forms of construction interface.
Concrete can shrink 0,1–0,5 ‰,
depending on environmental con-
ditions. This means that the higher
the relative humidity is, the lower
the shrinkage is.
1.1.1.4.5 Cracking
Concrete is placed while in a wet
(or plastic) state, and therefore can
be manipulated and moulded, as
needed. The hydration and hard-
ening of concrete during the first
three days is critical and abnor-
mally fast drying and shrinkage
due to factors such as evaporation
from wind during placement may
lead to increased tensile stress at
a time when it has not yet gained
significant strength, resulting
in shrinkage cracks. The early
strength of the concrete can be
increased by keeping it damp for
a longer period during the curing
process.
Minimizing stress prior to curing
minimizes cracking. High early-
strength concrete is designed
to hydrate faster often by the
increased use of cement, which
increases shrinkage and crack-
ing. by its very nature, concrete
shrinks, and therefore cracks.
Plastic-shrinkage cracks are
immediately apparent, i.e. visible
within 0 to 2 days of placement,
while drying-shrinkage cracks de-
velop over time. Precautions such
as mixture selection and joint
spacing can be taken to encourage
cracks to occur within an aesthetic
joint, instead of randomly.
engineers are familiar with the
tendency of concrete to crack,
and, where appropriate, special
design precautions are taken to
ensure crack control. This entails
the incorporation of secondary
reinforcing placed at the desired
spacing to limit the crack width
to an acceptable level. Water
retaining structures and con-
crete highways are examples of
structures where crack control
is exercised. The objective is to
encourage a large number of
very small cracks, rather than a
small number of large, randomly-
occurring cracks. Picture 1.3
shows the principle of cracking,
which means, that cracks occur in
places where concrete is sub-
jected to tension. Reinforcement
bars are located in places where
tension takes place. Reinforce-
ment bars will take up the tension
load, and they also function as a
warning mechanism. That means
that before the construction totally
collapses, correctly designed
reinforcement permit the cracks
to grow visible enough and the
overloading of construction can be
discovered during inspections.
PICTURE 1.2 Differentstagesofthecuringprocess
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
1.1.1.4.6 Creep
Creep is the term used to de-
scribe the permanent movement
or deformation of a material in
order to relieve stress within the
material. Concrete subjected to
forces is prone to creep. Creep can
sometimes reduce the amount of
cracking that occurs in a concrete
structure or element, however
it also must be controlled. The
amount of primary and secondary
reinforcing in concrete structures
contributes to a reduction in the
amount of shrinkage, creep and
cracking.
1.1.1.4.7 Typesofconcrete
There are many different types
of concrete available. The most
common is regular concrete, which
can be defined according to many
subclasses (Table 1.4).
Self-compacting concrete (SCC)
was first developed in Japan 1988
to reduce labour in the placement
of concrete by eliminating or reduc-
ing the need for vibration to achieve
consolidation. Self-compacting
concrete is often used in complex
or in close space reinforcement bar
structures.
Shotcrete or sprayed mortar is
commonly used e.g. in tunnels to
stabilize the walls of the tunnel.
Shotcrete was already invented in
the early 1900s. Up until the 1950s,
the wet-mix process was known,
with only the dry-mix process being
used. In the 1960s, the alterna-
tive method for gunning by the dry
method was devised with the devel-
opment of the rotary gun.
Pervious Concrete is a special type
of concrete allowing high volumes
of water to run through it. environ-
mentally, it makes good sense to
let rainwater directly recharge our
groundwater. Pervious can miti-
gate “first flush” pollution protect-
ing our streams, water-sheds and
ecosystems. Pervious does not
get as hot as standard cement and
asphalt.
Cellular or aerated concrete is a
light weight concrete, the volume
of which is only 20 % solid mate-
rial and the rest is porous. Aerated
concrete is mainly used in a differ-
ent shape of blocks.
Roller-compacted concrete or RCC
takes its name from the construc-
tion method used to build it. It is
placed with conventional or high-
density asphalt paving equipment,
and then compacted with rollers.
RCC has the same basic ingredient
as conventional concrete: cement,
water, and aggregates, such as
gravel or crushed stone. but unlike
conventional concrete, it is a drier
mix - stiff enough to be compacted
by vibratory rollers. Typically,
RCC is constructed without joints,
requiring neither forms nor finish-
ing, nor containing dowels or steel
reinforcing. These characteristics
make RCC simple, fast, and eco-
nomical.
Asphalt concrete (cement re-
placed with bituminous) is also
one type of concrete. The terms
asphalt concrete, bituminous as-
phalt concrete, etc., are typically
used only in engineering jargon.
Asphalt pavements are often
called asphalt by laypersons, who
tend to associate the term con-
crete only with Portland cement
concrete.
1.1.1.4.8 Concretetesting
engineers usually specify the
required compressive strength of
COMPRESSIONNON-CRACKED CONCRETE
TENSIONCRACKED CONCRETE
COMPRESSIONNON-CRACKED CONCRETE
TENSIONCRACKED CONCRETE
COMPRESSIONNON-CRACKED CONCRETE
TENSIONCRACKED CONCRETE
TENSIONCRACKED CONCRETE
TENSIONCRACKED CONCRETE
TENSIONCRACKED CONCRETE
TENSIONCRACKED CONCRETE
PICTURE 1.3 Principleofcracking
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
concrete, which is normally given
in terms of 28-day compressive
strength in MN/m² or in N/mm².
Twenty eight days is however a
long time to wait to determine
wheter the desired strengths are
going to be obtained, so three-
day and seven-day strengths can
be useful to predict the ultimate
28-day compressive strength of
the concrete. A 25 % strength gain
between 7 and 28 days is often
observed with 100 % OPC (Ordinary
Portland Cement) mixtures, and
frequently a 40 % strength gain
can be realized with the inclusion
of pozzolans and supplementary
cementatious materials (SCM’s)
such as fly ash and/or slag cement.
Strength gain depends on the type
of mixture, including its constitu-
ents and the use of standard curing,
proper testing and care of cylinders
in transport, etc. it becomes imper-
ative to equally rely on testing the
fundamental properties of concrete
in its fresh, plastic state.
Concrete is typically sampled while
being placed with testing protocols
requiring that test samples be cured
under laboratory conditions (stan-
dard cured). Additional samples may
be field cured (non-standard) for the
purpose of early stripping strengths,
i.e. form removal, evaluation of cur-
ing, etc. However the standard cured
cylinders comprise acceptance
criteria. Concrete tests measure the
“plastic” (unhydrated) properties of
concrete prior to, and during place-
ment. As these properties affect the
hardened compressive strength and
durability of concrete (resistance
to freeze-thaw), the properties of
TYPEOFCONCRETE DESCRIPTION
CEMENTCONCRETEThis is the most common type of concrete and is made mostly from Portand cement, sand, aggregate and water. It is used to reinforce and un-reinforce structures, roads and foundation. The compositions of cement, sand and aggregate vary from 1:1:2 (a richest practical mixture) to 1:3 :6 (a lean mixture used for concrete filling).
PLAINMASSCONCRETE Concrete not strengthened by reinforcement. Used for foundations and mass structures such as dam, and gravity retaining walls. Also called non-reinforced concrete.
LEANCONCRETE A plain concrete with a large ratio aggregate to cement than structural concrete. It is used for filling and not structural purposes.
STRUCTURALCONCRETElightweight concrete of such a quality is suitable for load-bearing members of structures. If it is a compact concrete made with stone aggregate, it is of comparatively high density (about 2.4) and great strength. If it is based on lightweight aggregate, then high strengths are available but the design generally requires special considerations.
REINFORCEDCONCRETElightweight concrete of such a quality is suitable for load-bearing members of structures. If it is a compact concrete made with stone aggregate, it is of comparatively high density (about 2.4) and great strength. If it is based on lightweight aggregate, then high strengths are available but the design generally requires special considerations.
PRESTRESSEDCONCRETE Structural concrete which is subjected to compression in those parts which in service are subjecte to tensile forces so that generally, the concrete is nowhere is a state of tension under the working load.
CASTINPLACE/CASTINSITUCONCRETE
This is deposited in its permanent position to harden. This is the most common method of construction and when to concrete is not deposited on the ground, such as for roads and similar purposes, it is generally placed in temporary moulds or is contained within a formwork or shuttering.
PRECASTCONCRETE
This is concrete placed in separate moulds under controlled factory conditions to harden and required to be transferred to a site for final construction. This procedure allow high quality concrete castings to be made at low relative costs. This method is used for the production of paving slabs, bricks, road channels, kerbs lintels, fence posts, bridge beams, etc. Precast units can include re-inforcement and engineered steel inserts.
VACUUMCONCRETE
This is concrete containing high water content to allow sufficient workability to enable it to be placed into complicated moulds or around extensive reinforcement. The concrete is then subject to a vacuum removing significant quantities of water resulting in a stronger concrete on hardening. Pumped concrete needs to include higher water content to improve the flow characteristics. If a high strength concrete is required then special additives are use in place of the additional water. A concrete pumping station may be static or mobile.
PUMPEDCONCRETEConcrete conveyed from the mixer to the point of deposit through pipes. The concrete is discharged from the mixer into a hop-per which feeds it into a pump which forces it through the pipe. The pipe is 100 or 150 mm dia and the method can be used to pump over distances of 650 m horizontally or 50 m vertically, or some combination of these lengths.
SPUNCONCRETE This process used for the production of vessels and pipes involves feeding relatively dry concrete into a rotating cylindrical mould. The concrete is flung against the wall by a centrifugal action to form a dense hard impermeable wall.
READYMIXEDCONCRETEConcrete made at a mixing plant and delivered to the site in special transport vehicles. The transport includes a rotating drum in which the concrete is continuously mixed until it is discharge on site. The mix specification is agreed upon between the sup-plier and the user prior to delivery and generally results in a high quality product.
WATERRESISTANTCONCRETE
Water Resistant concrete can either be water proofed or watertight. • Waterproof concrete is formed with a water resistant layer or surface with the mass of concrete remaining ordinary concrete. The water tight layer can be formed using a spray of lacquer, or applying a coat of asphalt or bitumen or using a wash of soda (water glass) • A watertight concrete can be produced by ensuring and dense product using tight quality control of the production process. The resulting can be sufficiently watertight to enable it to be used for tanks retaining water
HIGHDENSITYCONCRETE High density concrete for use as nuclear shield walls and ballast blocks and sea walls can be produced by using different materials for the aggregate. Candidate materials include barytes, haematite, iron shot, steel shot and lead shot.
FIBREREINFORCEDCONCRETE
High strength high performance concrete can be produced by including short fibres in the mix. A number of reinforcement materials are available including glass, nylon, polypropylene, carbon and steel. Concrete in such a form leads to increased strength, impact resistance and greater strength. This is an area of concrete development which is continuously being devel-oped.
TAble 1.4 TYPESOFCONCRETE
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
slump (workability), temperature,
density and age are monitored to
ensure the production and place-
ment of ‘quality’ concrete. Tests are
performed according to european
methods and practices. Techni-
cians performing concrete tests
must be certified. Compressive
strength tests are conducted using
an instrumented hydraulic ram to
compress a cylindrical sample to
failure. Tensile strength tests are
conducted either by a three-point
bending of a prismatic beam speci-
men or by compression along the
sides of a cylindrical specimen.
1.1.2 NATURALSTONE
The globe is an amazing and compli-
cated structure (Picture 2.1). The core
of the globe is formed of solid iron
(Fe) and nickel (Ni). This solid core is
surrounded with liquid Fe-Ni-core.
Around this liquid core is a so-called
mantel. Mantel is formed of iron sul-
phates and Fe- and Mg-silicates. The
hard surface of the globe is called
crust. Those stones used for con-
structions are mined from crust.
1.1.2.2 Materialdescription
A rock is an aggregate composed
of grains of minerals which are
cemented. The rocks occurring in
the crust can be divided into three
groups: magmatic rocks, sedimen-
tary rocks and metamorphic rocks.
1.1.2.3 Rocktypes
Magmatic rocks - rocks formed 1.
during the crystallization of
magma (melted rock).
Sedimentary rocks - rocks 2.
formed during the lithification of
sediment.
Metamorphic rocks - rocks forming 3.
during metamorphism (i.e. transfor-
mation) of previously existing rocks.
See the rock types from picture 2
1.1.2.4 Commercialtypesand
geologicalnames
Commercial names for different
types of stones are often different
from geological names. Table 2.1
compares some commercial and
geological names.
1.1.2.5 Characteristics
1.1.2.5.1 Strength
Different rock types have differ-
ent strengths. Generally speaking,
granites are the most common form
of hard rocks. Slates and marble
are normally slightly softer than
granites. Sand-stones, soapstones
and limestones are significantly
softer than granites. Table 2.2 shows
the typical strengths of different
types of stones.
1.1.2.5.2 Applicationsandsuitability
Stones can be used in different
types of constructions. Table 2.3
shows some constructions where
stones can be used. The usage tar-
gets of different type of stones vary
according to weather conditions
and common habits.
1.1.3 SOLIDANDHOLLOWBRICK
PICTURE2.2 Rocktypes
CRUST AND UPPER PART OF MANTLE FORM
LITHOSPHERE
MANTLE- IRON SULPHATES AND FE- AND MG-SILICATES
- UPPER PART OF MANTLE IS PARTLY MOLTEN- FLOW OF UPPER PART OF MANTLE MOVES
PLATFORMS IN LITHOSPHERE
LIQUID FE-NI-CORE
CRUST- SEA AREAS 6-7 KM
- CONTINENTS 35-40 KM
SOLID FE-NI-CORE
PICTURE2.1Structureoftheglobe
GRANITE-AMAGMATICROCK
SANDSTONE-ASEDIMENTARYROCK
ECLOGITE-AMETAMORPHICROCK
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TAble 2.1 COMMERCIALANDGEOLOGICALNAMES
INDUSTRIALTYPE GEOLOGICALNAME
GRANIITTI Syenite, granite, granodiorite, dioriitti, gabro, anortosite, diabase, migmatite, gneiss
SLATE Quartsite, mica schist, fyllite, amfibolite
MARMOR Marmor, limestone, dolomite, travertine
SANDSTONE limestone, sandstone
SOAPSTONE Soapstone, serpentine
LIMESTONE limestone, dolomite, travertine
TAble 2.2 STRENGTHSOFSTONES
ROCKTYPE DENSITY kg/m³
WATERAB-SORBTION
wt%
COMPRESSIVESTRENGHT
N/mm²
FLEXURALSTRENGHT
N/mm²
GRANITE 2 580 - 3 080 0,084 - 0,35 150 - 300 8,25 - 26
SLATE 2 500 - 2 800 0,1 - 0,4 100 - 200 10 - 35
MARMOR 2 600 - 3 000 0,2 - 0,6 80 - 180 6 - 20
SOAPSTONE 2 760 - 2 980 0,1 - 0,24 25 - 135 8 - 12,5
TAble 2.3 DIFFERENTAPPLICATIONS
XXVERYSUITABLE
XSUITABLE
X*NOTINSCANDINAVIA
FLOORSANDSTAIRS(INDOOR)
INDOORWALLS
KITCHENSURFACES
FIRE-PLACES
FACADESFOUNDA-TIONS
WALLSANDENVIROMENTALSTRUCTURES
STAIRS(OUTDOOR)
PAVINGS
GRANITE
cleavage plane x x xx xx xx xx xx
burned x x x xx xx xx xx xx
cut x x xx xx xx xx xx
ground xx xx xx x xx xx x x x
polished xx xx xx x xx xx x x x
SLATE
cleavage plane xx x x xx xx xx xx xx
ground x x x xx xx xx xx x
MARBLE
polished xx xx x x* x* x* x*
SOAPSTONE
cleavage plane x xx x x x
polished xx xx xx x x
1.1.3.1 History
Indications of the earliest use of
brick as a building material go
back about 5,000 to 6,000 years
in the archaeological ruins of our
history. Where, when and by whom
the first bricks were formed and
assembled, no one can say.
The first brick buildings were built in
Ur in Mesopotamia about 4000 bC.
bricks have also been used in egypt
already 3000 bC. At that time clay
was also used as a raw material,
but it was dried rather than burned.
burning bricks has been known
since about 2200 bC in Mesopotamia.
1.1.3.2 Materialdescription
brick is a building material, which
consists of dried and fired clay and
sand. Normally brick has a rectan-
gular shape. The colour of the brick
is dependent on the iron contents
of the clay. The colour can be red or
yellow, for example.
There are sometimes holes added
inserted in the bricks, which in-
crease the compression strength
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
of the brick. Also sawdust can be
added to make bricks more frost
proof. Sand-lime brick is a product
that uses lime instead of cement.
It is usually a white brick made of
lime and selected sands (quarts
sand), cast in molds and cured
under steam. Some people don’t
even recognize sand-lime brick as
real brick.
1.1.3.3 Production
1.1.3.3.1 Clayextraction
The clay pit is usually nearby the
production plant. This reduces the
transportation distance to a mini-
mum. The clay is extracted from
the clay pit by means of modern
equipment, stored and transported
to the clay preparation unit (Picture
3.1).
1.1.3.3.2Claypreparation
Clay preparation means that the
clay is going to be grinded, milled,
wedded and foreign materials,
such as stones, will be removed
to achieve the right consistency
and homogeneity of the clay for
production (Picture 3.2). In order to
produce special colours, different
types of clay or mineral aggregates
can be added.
1.1.3.3.3 Theshapingprocess
Hand moulded brick: for mechani-
cally produced “hand” moulded
bricks, the raw material is, depend-
ing on the machine producing these
bricks, either rolled in sand or di-
rectly thrown forcefully into already
sanded moulds. The sand acts like
flour in a cake mould. The surplus
material is cut off from the top edge
of the moulds.
Stock bricks: The raw material is
pressed into the moulds already
sanded under high pressure (Pic-
ture 3.3). This results in bricks with
more subdued shapes and surface
structures, and akin to hand-
moulded bricks, five surfaces of
the brick are sand-coated.
extruded bricks are produced by ex-
trusion. Under high pressure, the raw
material is forced through a die. The
produced endless run of clay is cut
into the thickness of the green brick
by a taut wire.
1.1.3.3.4 DryingandFiring
by using the excess heat energy of
the kiln, the green bricks are dried
until nearly all moisture has been
removed after which the unfired
brick is prepared for the following
firing process in the kiln
At a temperature of about 1.050°C,
for pavers over 1.100°C, bricks are
fired in the kiln. Today the fiing pro-
cess usually takes place in modern,
computer controlled tunnel kilns
(Picture 3.4). but there are still some
traditional ring kilns and clamps at
work to produce bricks with a very
special look. by using special firing
methods, such as using a reducing
kiln atmosphere, it is possible to
produce exceptional colours.
1.1.3.4 Characteristics
As long as humans have made
bricks, the shape and characteris-
tics of bricks have varied. even to-
day most countries have their own
style of bricks which differ from
those of other countries. The fol-
lowing list mentions some principal
characteristics of modern bricks in
europe.
• Compression strength 30 - 45 N/
mm² (could also be 7 - 105 N/mm²)
• Compression strength for hollow
bricks even higher
• Tensile strength about 4-5 % of
compression strength and for
hollow bricks even less
• Resistance to moisture is good
and the coefficient of moisture
expansion is very low
• Coefficient of thermal expansion
is low (3-5 x 10-6)
• Fire resistant
• Splits easily
• Hollow bricks have good resis-
tance to freeze-thaw
PICTURE3.4 Tunnelkiln
PICTURE3.1 Extractedclay
PICTURE3.2 Claypreparationinprogress
PICTURE3.3 Shapingbricks
1.1 bASe MATeRIAl
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1.1.4 SAND-LIMEBRICK
1.1.4.1 General
Sand-lime brick is known and used
internationally since it was pro-
duced for the first time in history in
britain in 1886. Some people don’t
even recognize sand-lime brick as
real brick. It distinguishes itself
by its exact geometrical dimen-
sion, nice shape, high strength and
glazed surface.
1.1.4.2 Production
Sand-lime bricks are made of a
mixture of lime, quartz sand and
water. bricks are moulded under
high pressure into meticulous
raw blocks. The final strength is
achieved in an autoclave under
pressure and temperatures of 160
to 200 ºC. In the tempering pro-
cess lime reacts with quartz sand
and forms silicate bonds. Coloured
sand-lime bricks are produced
by adding UV and alkaline re-
sistant pigments (Picture 4.1).
White bricks are made of crushed
quartzite.
1.1.4.3 Characteristics
Compression strength 15…25 •
MN/m²
Density 1700…1900 kg/m³•
Shrinkage and moisture expan-•
sion about 0,2 mm/m
Water absorbing capacity 10…17 %•
Water absorbing speed 1…2 kg/•
m² min
Coefficient of thermal expansion •
(8 x 10-6)
Good moisture resistance•
Heat resistance up to +600 ºC•
Good resistance to freeze-thaw•
1.1.5 AERATEDCONCRETE
1.1.5.1 History
Finland and Sweden developed
aerated concrete in the 1920s
and 1930s. The Finnish chemist
lennart Forsén and the Swedish
chemist Ivar eklund discovered
a mixture of cement, lime, water
and sand that expands by adding
aluminium powder. Akin to wood
but without the disadvantages of
combustibility, decay, and termite
damage, the material was further
developed to what we know today
as autoclaved aerated concrete
(also called autoclaved cellular
concrete or ACC).
1.1.5.2 Materialdescription
In its manufacture, Portland cement
is mixed with lime, silica sand, or
recycled fly ash (a byproduct from
coal-burning power plants), water,
and aluminium powder or paste and
poured into a mould. Steel bars or
mesh can also be placed into the
mould for reinforcement.
Reinforcing bars must be protected
with anticorrosion paste. The
reaction between aluminium and
concrete causes microscopic hy-
drogen bubbles to form, expanding
the concrete to about five times its
original volume.
After the hydrogen evaporates, the
now highly closed-cell, aerated
concrete is cut to size and form
and steam-cured in a pressurized
chamber (an autoclave, 180 °C and
11 bar). The result is a non-organic,
non-toxic, airtight material that can
be used in non- or load-bearing
exterior or interior wall, floor, and
roof panels, blocks, and lintels. Ac-
cording to the manufacturers, the
production process generates no
pollutants or hazardous waste.
1.1.5.3 Characteristics
• 400 kg/m³ - 600 kg/m³, see also
table 5.1, (in some countries
even higher)
• light weight: normally 75 %
lighter than normal concrete
• easy to work
• Durable: resists decay and insects
• Fire resistant
• Sound absorptive
• Porous: 20 % solid material, 50 %
macropores 0,5 - 2 mm and 30 %
micropores (500 kg/m3)
• Shear strength about 2 - 3 %
from compression strength
• Creep and shrinkage is low
(hydroexpansivity 0,02 ‰)
PICTURE4.1 Differentcoloursofsand-limebrick
TAble 5.1 MAINCHARACTERISTICS
DENSITYkg/m³
COMPRESSIONSTRENGHT
N/mm²
FLEXURALSTRENGHT
N/mm²
MODULUSOFELASTICITY
N/mm²
400 1,7 0,3 1 000
450 2,3 0,44 1 200
500 3,0 0,58 1 400
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SORMAT Technical manual 07/2008
1.1.6 LIGHTWEIGHTEXPANDED
CLAYCONCRETEORLIGHT
GRAVELCONCRETE
1.1.6.1 Materialdescription
light gravel is made of clay baked
in a rotating oven over 1 100 °C
degree (Picture 6.1). The rotation
gives clay its round shape and
smooth surface. The grain has a
compact surface, but the inside of
the grain is porous and the grain
size is 1–32 mm. The porosity
makes it light with good thermal
insulation ability. light gravel is
not only used in light gravel blocks,
but also in concrete (Picture 6.3) as
an insulation material.
1.1.6.2 Characteristics
The nominal density of light gravel
block is 650 kg/m³ or heavier
950 kg/m³. This means that the
compression strength varies from
3 MN/m² to 5 MN/m². The com-
pression strength is high enough
in the normal usage of light gravel
blocks, such as in foundations
and wall construction. For ex-
ample, one 590 x 290 x 190 mm³,
3/650-block can bear 130 kN = a 13
ton uniform load before it breaks.
The hollows in the blocks vary ac-
cording to different block types and
also producers manufacture differ-
ent products (Picture 6.2).
1.1.7 PLASTERBOARD
1.1.7.1 History
Gypsum, the first mortar binder
produced by burning and it was
already used in ancient egypt and
Rome. Gypsum landed in europe in
the 17th century when the French
and the english started to use it as
a building material. It was mainly
used for decorations and for indoor
plastering. Plasterboard was
invented at the end of 19th century.
The modern type of plasterboard
was patented in the USA in 1908.
The first plasterboard factory was
introduced in europe in 1917. Since
then, plasterboard has also been
used in Finland.
1.1.7.2 Materialdescription
Plasterboard (also called wall-
board, gypsum board, GWb, and
drywall) is a building material con-
sisting of gypsum formed into a flat
sheet and sandwiched between two
pieces of heavy paper. 94 % of the
weight is gypsum and 5 % paper.
1 % consists of water, starch and
admixtures. As of 2005, it is the
most commonly used material
globally for constructing interior
walls and ceilings.
1.1.7.3 Characteristics
Normal gypsum board
• Density 9,0 kg/m²
• bending stiffness 2,0 – 2,5 N/mm²
• When RH > 90 % à strength will
decrease
• Deformation RH 40 % - 90 % à
0,4 mm/m
• Working temperature < 50 ºC
• emission class M1
• Slow down fire
• Capillary rise at least 1 m
• Cardboard works akin to rein-
forcement bars in concrete
1.1.8 Shapeoftheconstruction
The shape of the construction is
limited quit often by the selection of
the anchoring method. Thin slaps
limit anchoring depths and the
same problem also arises with thin
walls. especially narrow beams and
columns pose challenges to an-
choring. In engineering and instal-
lation, it is important to pay atten-
tion to installation depths as well
as to splitting forces. For example,
all ordinary expansion anchors may
be ruled out because of too high
expansion forces.
PICTURE6.1 Expandedclaygrains
PICTURE6.3 TWA-terminal,KennedyAirportN.Y,USA1956-1962,architectEeroSaarinen
PICTURE6.2 Differentsshapesoflightgravelblocks
1.1 bASe MATeRIAl
SORMAT Technical manual 07/2008
1.2 USAGETARGET
1.2.1 CONSTRUCTION
Construction can be bearing or
non-bearing. bearing construc-
tions are submitted to loads which
strain construction. This strain can
lead to cracking of the construc-
tion and therefore cracking must
be noticed by the design of the
anchorage. Although non-bearing
construction does not take vertical
loads, it is able to take horizontal
loads, e.g. rigid wall.
1.2.2 CORROSION
ever since metallic materials have
been used in the construction in-
dustry, building and civil engineers
have faced problems of corrosion
and designing protection against
corrosion. As early as the Middle
Ages, fasteners made of iron and
iron alloys were used, e.g. as
staple-like clamps and fasteners,
for securing building components.
They were positioned in such a way
that they remained accessible and
could be maintained. Recently,
however, engineers believed that
corrosion problems could be
overcome by using stainless steel
and covering steel members and
components more carefully with
concrete. During past decades,
there has been a great increase in
the exposure of certain areas to
pollutants, e.g. technical facilities
for traffic. This trend has resulted
in previously used materials reach-
ing the limits of their capabilities.
even today, materials used for
building and structures situated
in corrosive environments have an
unsatisfactory service life in many
cases.
In the field of composite con-
struction, in particular, problems
resulting from corrosion are not
restricted only to zones exposed to
the atmosphere. As a rule, a cor-
rosive medium gains access to a
metal connector or other fastener,
etc. through, for example, cracks
which appear in concrete or gaps
which exist in structure. Gaps of
this kind can be the result of the
structural design, such as those
gaps between the original concrete
and a concrete overlay on repaired
bridges. In the course of time
pollutants, such as chlorides and
corrosive acids, can accumulate,
producing considerably more cor-
rosive conditions in this way.
Corrosion seriously impairs the
functioning and service life of an-
chors as well as of other fasteners,
as a result possibly creating a con-
siderable safety risk. Several field
tests and laboratory tests by differ-
ent manufactures and universities
in different environments, such as
tunnels, indoor swimming pools,
power plant chimneys, have been
conducted proving that it is neces-
sary to pay attention to the right
materials. For example, it was
found that the high-alloyed auste-
nitic steel according to eN 1.4529 or
similar, which has a molybdenum
content greater than 6 % (and nickel
content high over 20 %), is ideal for
use in construction in highly cor-
rosive surroundings (chlorides and
sulphur dioxide).
In addition to conventional corro-
sion, there are also other types of
corrosion that occur on fasteners,
such as galvanic corrosion (contact
corrosion), stress corrosion, pitting
corrosion and crevice corrosion.
1.2.2.1 Galvaniccorrosion
Galvanic corrosion is corrosion
that occurs between two different
grades of metals, where the least
noble (base) metal is corroded
through electrolytic contact with
the nobler metal. This type of cor-
rosion may pose a major risk when
the fitting is made of a less noble
metal and is significantly smaller
than the piece being mounted. This
risk can be avoided by not using
different metals together or by iso-
lating the metals from one another
with, for example, plastic insulat-
ing washers.
1.2.2.2 Stresscorrosion
Stress corrosion is a very difficult
type of corrosion to detect. It oc-
curs in fittings which are under
tension and exposed to chloride in
warm conditions. Fittings used in
the suspended ceilings of indoor
swimming pools are typically sus-
ceptible to this type of corrosion.
In such areas, not even A4 grade
stainless steel provides adequate
corrosion resistance instead eN
1.4529 or similar grade steel
should be used.
1.2.2.3 Pittingcorrosion
Pitting corrosion involves the
corrosion of metal in small areas
on the metal surface, resulting
in localized ‘pits’. Pitting cor-
rosion rarely advances through
solid structures. Generally, the
corrosion stops when the pits
have reached a certain depth. The
passive layer on stainless steel is
a gel-like, hydrated oxide film a
few nanometres in thickness. In
chloride solutions the chloride ions
displace water molecules in the
passive layer. Hydrated metal ions
normally part of the passive layer
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and found in its flaws, dissolve to
form metal chloride complexes,
which diffuse even further. This
leaves a gap in the passive layer
where the metal continues dis-
solving and pitting corrosion takes
hold. The susceptibility of stain-
less steel to pitting corrosion can
be reduced by means of doping.
The most effective doping agent
is molybdenum, but chrome and
nitrogen doping also have a reduc-
tive effect on the susceptibility of
pitting corrosion.
1.2.2.4 Crevicecorrosion
Crevice corrosion occurs in most
metals, ranging from noble metals,
such as silver and copper, to very
ignoble metals, such as titanium
and aluminium. Crevice corrosion
occurs in very tight cracks, into
which the solution penetrates, but
where it cannot circulate at the
same rate as in other areas of the
metal surface. When corrosion
strains and problems are exam-
ined more closely in the installa-
tion area, they usually lead to an
increase in the need for corrosion
protection. This, of course, re-
duces the risk considerably, while
enhancing the liability protection
of engineers and installers in any
problem case.
Crevice corrosion occurs when:
The geometric form or manufac-1.
turing technique of the struc-
ture is such that approximately
0,0025 - 0,1 mm gaps form in
areas where there is contact with
the solution. These gaps gener-
ally form at various rivets, bolts,
and weld joints.
At contact interfaces between 2.
metals and non-metals, such as
at seal joints, if the seal material
is, for example, water-absorbent
or does not completely cover the
seal surface.
There are various solid particles 3.
on the metal surface, such as
sand, dirt or precipitates formed
by corrosion products.
1.2.3 CORROSIONPROTECTION
1.2.3.1 Electroplating
electroplating (zinc plating) is a
sacrificial coating, which corrodes
instead of the underlying steel and
is normally 5–12 μm (micrometres)
in thickness. In a dry climate an
oxide layer forms on its surface
to protect the zinc from advanc-
ing corrosion. However, if there
is any moisture and air present,
the zinc coating will corrode and
turn into basic zinc carbonate. A
basic zinc carbonate is sometimes
referred to as “white rust”. The
zinc carbonate is sloughed off by
air currents or rain and, over time,
the zinc gradually disappears. Pas-
sivization, which can be yellow or,
nowadays often nearly clear, pro-
tects the zinc coating from chemi-
cals present in the packaging. It
provides protection for the zinc
coating and keeps the fittings in
good condition before their instal-
lation. electroplated products are,
however, only suitable for use with
installations in dry, indoor spaces.
1.2.3.2 Hot-dipgalvanization
Hot-dip galvanization is the next
step up in corrosion protection. It
has a thicker layer of zinc (ap-
prox. 45 μm), which generally lasts
longer, but will corrode over time
in damp or wet conditions. Hot-dip
galvanized products are generally
suitable for use in rural or urban
environments for as long as 10
years, and in industrial and marine
environments for 2–3 years. Regu-
lar inspections are always recom-
mended. It must, however, be kept
in mind that in highly polluted
areas, the zinc can corrode consid-
erably faster, while in leaner areas
it can last significantly longer,
even longer than the specifications
estimate. Always remember that
coatings are sensitive to damage,
particularly during installation.
Zinc is not usually able to repair
major damage by itself, thus mak-
ing the product quickly susceptible
to corrosion and even resulting
in a serious safety hazard. This
is why zinc coated fittings are not
recommended for use in long-term
exterior installations.
1.2.3.3 Stainlesssteel
Stainless steel comes in six differ-
ent grades (A1, A2, A3, A4, A5 and
HCR), but, in practical terms, only
three of these grades are used
in anchors: two standard grades
and one special grade usually only
available upon special order. The
least corrosion-resistant grade
is A2. A2 contains chrome and
nickel and is suitable for use in
long-term exterior installations in
areas where the air is not polluted
and there is no chlorine present.
This primarily covers or applies
to rural and sparsely populated
areas. even though A2 will not rust
in these conditions, it may still lose
its sheen, thus giving decorative
structures a smudgy appearance.
A4 provides better corrosion-re-
sistance. In addition to chrome and
nickel, this grade also contains
molybdenum. Its surface does not
become smudgy in outdoor use
and it can be used in just about any
type of outdoor structure, includ-
1.2 USAGe TARGeT
SORMAT Technical manual 07/2008
ing industrial and marine environ-
ments and even underwater instal-
lations, however not in coastal
areas, where saltwater spray can
reach the fittings. Special-grade
stainless steel is recommended
for use in coastal areas. Special-
grade stainless steel (HCR) is a
specialized alloy, containing larger
concentrations of chrome, nickel
and molybdenum than the alloys
mentioned above. Special-grade
stainless steel is identified by its
code, for example, eN 1.4529. The
material can be used in all types
of aggressive climates, including
areas subject to sea spray. Other
aggressive climate areas include
various types of chemical plants,
tunnels, and indoor swimming
pools.
1.2.3.4 Sherardization
Sherardization is more environ-
mental way of galvanizing than
hot-dip galvanizing. Articles, which
are cleaned by etching, are placed
into rotating reel oven with zinc
powder and sand. Oven is warmed
up, close to melting point of zinc,
and after certain time steel and
zinc will react (diffusion), and iron-
zinc coating will be formed on sur-
face of the steel. Coating thickness
is normally 15–40 μm and colour is
dark grey.
1.2.3.5 Mechanicalgalvanizing
Articles, which are degreased, are
placed into a rotating reel oven
with glass balls where acid clean-
ing will be carried out. After the
coppering treatment, zinc powder
and some chemicals are added to
the reel oven. The normal coating
thickness is 12–15 μm. However
thicker layers are also possible
(up to 75 μm). The coating thick-
ness is very even and the colour is
grey. There is no risk of hydrogen
embrittlement, which explains why
hardened steels are also treatable.
1.2.3.6 DeltaCoating
Delta coating is comprised mainly
of overlapping zinc and aluminium
flakes in an inorganic binder. The
applied and cured coating forms
a 97 % zinc-rich structure of
laminated zinc flakes. The coating
thickness varies 15–20 μm and the
colour is silver.
1.2.3.7 DacrometCoating
Dacromet Coating is similar to
Delta Coating.
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1.3 LOADSANDRESISTANCES
1.3.1 LOADTYPES
1.3.1.1 Staticloads
Static loads refer to for example,
a dead load (own weight), loads of
non-bearing structures and loads
due to temperature changes or
movement of supports. All kind of
equipments and furniture are also
defined as static loads. Nature also
creates static loads, e.g. snow,
wind and temperature. When we
consider anchor design, generally
about 95 % of the cases concen-
trate on static loads.
1.3.1.2 Dynamicloads
A dynamic load is a load associ-
ated with the elastic deformations
of a structure subjected to time-
dependent external forces. The
main difference between static
and dynamic loads is the effective-
ness of inertia and damping force.
Dynamic loads can be classified
into fatigue loads, seismic loads/
pulsate and shock loads.
1.3.1.2.1 Fatigueload
Fatigue loads can be divided into
two main groups:
Vibration (very high repetition •
rate and low amplitude range).
Frequent loading and unloading •
(high loads and frequent repetition).
Fatigue loads create changes in
stress in the anchors. Stress de-
creases the strength of the mate-
rial and this decrease is greater
subject to the change in stress
and the increase in the number of
cycles.
1.3.1.2.2 Shockload
Shock loads are loads with a very
short duration but extremely high
force. loads occur mainly as single
peaks. Shock loads are, generally
speaking, quite rare loading situa-
tions. However sometimes they are
the only loading case a structure is
designed for, e.g. explosions, crash
barriers, falling rocks, etc.
1.3.1.2.3 Seismicload
Seismic loads appear naturally in
seismically active areas. An earth-
quake moves the ground, leading
to the displacement of a founda-
tion. Due to its inertia of mass,
the building is unable to follow the
movements, causing a deformation
of the building. Due to the stiffness
of the building, restoring forces are
set, resulting in vibrations. Due to
the resonance phenomenon, the
larger range of vibrations are often
measured on the upper floors.
1.3.2 LOADCOMBINATIONS
Anchors can be subjected to
different kinds of loads (Picture
3.1). A load can refer to tension,
pressure or even only a share. In
most cases, however, the anchor
is subjected to a combination of
loads. load combinations increase
the complexity of the anchor
design because when we consider
the tension load and the share load
separately, it is possible that the
anchor is able to resist both loads.
A combination of these loads
can at any rate turn the situation
upside down, i.e. anchor will fail
under a combined load. Picture 3.1
shows different loads and combi-
nations.
N
N
N
V
V FR
N
e
VM
FR
e
VM
M
PICTURE3.1 Loadsandcombinations
1.3 lOADS AND ReSISTANCeS
BACKTOMAINMENU
SORMAT Technical manual 07/2008
1.3.3 RESISTANCEOFTHEANCHOR
The resistance of the anchor
depens on the type of the anchor.
The anchor can be an expansion
anchor, undercut anchor, screw
anchor or chemical anchor. each
anchor type has its own char-
acteristics in different service
conditions. It is very important
to notice and understand these
characteristics. Different types of
anchors are handled more closely
in chapter 1.5.
The resistance of the anchor is
greatly influenced by the base
material. The type and condition of
the base material is critical. The
base can be concrete (non-cracked
or cracked), masonry, aerated con-
crete or light aggregate concrete.
The softer or porous the mate-
rial, is the lower is the resistance.
Despite this fact the resistance of
the anchor is often strong enough
to overcome the strength of the
material. The situation is often dif-
ferent in non-cracked and cracked
concrete.
If a crack exists, the load bearing
mechanisms are seriously dis-
turbed because no ring-shaped
tensile forces can be taken up
beyond the edge of the crack. This
will reduce the load bearing capac-
ity of the anchor system. The width
of a crack in the concrete has a
major influence on the tensile
loading capacity of anchors. In the
official approvals the crack width is
limited up to 0,3 mm, eliminating
the need to have comprehension
charts between tension forces and
crack widths.
1.3.4 FAILUREMODES
Anchors can fail for different rea-
sons. That’s why it is important to
make a distinction between failure
modes caused by tension load and
share load.
1.3.4.1 Tensionload
The following failure modes are
valid for expansion and undercut
anchors. The same kind of failure
modes can also occur in chemical
anchors (Picture 5.3).
When a pull-out occurs (Picture
3.2a), the anchor is extracted or
removed from the hole without
remarkable damage to the hole.
The shallow surface cone may be
noticed, but it is irrelevant to the
break load. Pull-out failure can
occur in undercut anchors only if
the mechanical interlock is inad-
equate. Curve 4a in picture 3.3
demonstrates a representative
load-displacement relationship for
a drop-in anchor. Pull-out failure
can also occur for torque controlled
expansion anchors when the follow-
up expansion of the anchor does not
develop properly (Picture 3.3 curves
4c and 4d). Curve 4b in picture 3.3
shows the load-displacement be-
haviour for an undercut anchor as a
result of a pull-out.
Pull-through (Picture 3.2b),
where the cone is pulled through
the expansion clip, is unique to
the torque controlled expansion
anchors. It is a failure mode that is
consistent with the correct func-
tion of the anchor. The ultimate
capacity is, however, reduced,
compared with an anchor of equal
embedment failing by concrete
cone failure. The load-displace-
ment behaviour is similar to un-
dercut anchor by pull-out failure
(Picture 3.3 curve 4b).
As a result of concrete cone
failure (Picture 3.2c), the anchor
creates a cone formed concrete
fragment starting through the
expansion or undercut zone of the
anchor. If several closely spaced
anchors are used in the same
base plate, then a combined con-
crete cone failure may occur (Pic-
ture 3.2d). If anchor is installed
near to the edge of concrete, the
breakout cone will resemble pic-
ture 3.2e. The load-displacement
curve for concrete cone failure is
shown in picture 3.3 curve 2.
In general, splitting failure oc-
curs when the dimensions of the
concrete block are limited (Pic-
ture 3.2f). As a result of splitting
failure, the whole concrete block
can split or splitting can oc-
cur between two closely spaced
anchors. Moreover reduced edge
distances can lead to splitting.
The load-displacement curve for
splitting is shown in picture 3.3
curve 3.
The failure of the steel stud, bolt
or nut represents the highest
achievable load bearing capacity
of the anchor (Picture 3.2g). Steel
failure occurs rarely and then only
in high-strength concrete. The
load-displacement curve for steel
failure is shown in picture 3.3
curve 1. Note that this anchor has
a deeper embedment depth than
the anchor associated with curves
2, 3 and 4.
1.3 lOADS AND ReSISTANCeS
SORMAT Technical manual 07/2008
PICTURE3.2 Failuremodesduetothetensionload
A)PULL-OUT B)PULL-THROUGH C)CONEFAILURE,ONEANCHOR D)CONEFAILURE,SEVERALANCHORS
E)CONEFAILURE,EDGE F)SPLITTINGFAILURE G)STEELFAILURE
LOAD F
DISPLACEMENT
1 STEELFAILURE
2 CONCRETEFAILURE
3 SPLITTINGFAILURE
4APULL-OUT,DROP-INANCHOR
4BPULL-OUT/PULL-THROUGH
4CPULL-OUT
4DPULL-OUT
1
2
3
4A
4B
4C
4D
PICTURE3.3 Idealisedload-displacementcurvesfortensionloadedanchors.
1.3 lOADS AND ReSISTANCeS
SORMAT Technical manual 07/2008
1.3.4.2 Shearload
The shear load is resisted first via
friction generated by the preload
in the anchor. When the shear
load exceeds the available friction
resistance, the base plate slips
to engage the anchor in bear-
ing. As the shear load increases,
the bearing stress in the surface
concrete increases until a shallow
spall occurs which will increase
the lever arm and the associated
flexural stress in the anchor. With
a sufficient embedment depth, the
anchor may be capable of resisting
the load avoiding the failure of the
anchor bolt.
Anchors with sufficient edge
distances and embedment depths
can fail as a result of steel failure
(Picture 3.4a). For a given an-
chor, steel failure represents the
ultimate shear capacity. Relatively
large displacements can be de-
tected in anchors made of ductile
steels.
Short and thick anchors with limit-
ed embedment depth can produce
sufficient rotation to cause a pry-
out failure. Anchor groups can also
develop a common pry-out failure.
Pry-out failure is not dependent on
free edges (Picture 3.4b).
An anchor set close to the edge
and loaded in the shear towards
the free edge, may fail as a result
of development of a semi-conical
fracture surface in the concrete
(Picture 3.4c). A group of anchors
loaded in the shear may develop a
common conical fracture surface
(Picture 3.4d). An anchor installed
in the corner of the concrete
member can fracture the entire
corner of the member (Picture
3.4e).
PICTURE3.4 Failuremodesduetotheshareload
A)STEELFAILURE B)PRY-OUTFAILURE
C)EDGEFAILURE,ONEANCHOR D)EDGEFAILURE,SEVERALANCHORS
E)EDGEFAILURE,INTHECORNER
1.3 lOADS AND ReSISTANCeS
SORMAT Technical manual 07/2008
1.4INSTALLATION
1.4.1GENERAL
An anchor can work properly only
if it is correctly installed.
A drill hole has to be in the right
angle to the base material. It
should be observed that reinforce-
ment bars aren’t damaged or
drilled thorough. If reinforcement
bars are damaged, it could be pos-
sible that the load bearing capac-
ity of the construction is reduced
or even the load resistance of the
anchor may be reduced. That’s
why it is recommended accord-
ing to the design of anchorage to
place anchors to avoid contact with
reinforcement bars.
The fixing thickness has to be
chosen so that the thickness of the
non-bearing structure (plaster, in-
sulation, etc.) and the fixture thick-
ness are complied with. The holes
in the fixture should also conform
to the standard (see eTAG AnnexC,
Table 4.1) and these base plate
does not undergo deformation un-
der the load. This means that the
base plate has to be rigid and fully
placed against the base material,
excluding by distance installation.
If the bore holes in the fixture do
not conform to the standard, this
can cause decrease in the capacity
of the anchor.
1.4.2DRILLBITS
Carbide drill bits used for drill-
ing holes for anchors, should be
checked to meet the dimensional
requirements of anchor manu-
factures. This means that espe-
cially the measurements and the
concentricity of the tip need to
be checked. Typically either the
ISO-norm or the national norm are
used as a reference to determine
the suitability of the drill bit. Ap-
proved drill bits are marked with a
special sign (Picture 4.1). Further-
more all additional tools should
conform to the manufacture’s
recommendations. To achieve
the best performance of drill bits
and to avoid possible damage, the
drill should always conform to the
manufacturers’ recommendations
(speed of rotation/impact, frequen-
cy/impact force).
1.4.3 DRILLINGTECHNIQUES
Drilling techniques are often
undervalued, however, the right
drilling technique will even ensure
the proper function of the anchor.
Some base materials are very
sensitive to correct drilling and
they may even break as a result of
improper drilling. Moreover, the
service life of drill bits is affected
by the drilling technique; especial-
ly large drill bits are sensitive to
overheating, if the rotation speed
or impact frequency is too high.
Picture 4.2 shows various drilling
techniques and the recommended
usage targets.
PICTURE4.1 RockDrillAssociation(Prüfgemeinschaft
Mauerbohrere.V)Germany.Approvalforthedrillbit
accordingtoInstituteofConstructionTechnique(Institut
fürBautech-nik,Germany):Approvalsignforcarbide
cuttingtipdrillbits.
DIAMONDDRILLINGOnly rotation. Normally wet drilling, occasionally also dry drilling. Suitable for all base materials.
PICTURE4.2 Variousdrillingtechniques
NODRILLINGThe anchor is hammered or screwed into thebase material. For example light gravel concrete and aerated concrete.
NORMALDRILLINGFor materials with low compression strength.
IMPACTDRILLINGRotation + low impact force with high frequency.Solid base materials (drill bits under ø20 mm).
ROTARYHAMMERRotation + high impact force with low frequency.Solid base materials (all sizes).
1.4 INSTAllATION
BACKTOMAINMENU
SORMAT Technical manual 07/2008
1.4.3.1 Faileddrilling
Drilling can be described as failed, if
The drill hole is made in wrong •
position
The drill bit has touches the •
reinforcement bar and the re-
quired drill hole depth is not met
The reinforcement bar is con-•
tacted so that correct installation
of the anchor is not possible
If the drilling is abortive, the an-
chor should not be installed. It is
important to respect minimum dis-
tances between the failed drill hole
and the new drill hole. As a rule
of thumb, the following distances
can be used (Table 4.1). Always
remember to check precise values
from approvals or from product
information, if available.
1.4.4 EDGEDISTANCESANDSPACING
edge distances and spacing have
a significant influence on the ca-
pacities of the anchors. If smaller
distances are used, the capacities
must also be reduced.
The characteristic edge distances
define “critical zones” for the
placement of anchors with respect
to an edge. The critical edge zone
has a width equal to the character-
istic edge distance. The resistance
of anchors falling within the criti-
cal zone are reduced. For clarity,
picture 4.3 includes the prohibited
zone as well as the critical zone.
Characteristic spacing defines
a critical zone around a given
anchor for placing of further
anchors. The critical spacing zone
has a radius equal to the charac-
teristic spacing. The resistance of
anchors falling within the critical
zone are reduced. For the sake of
clarity, the picture 4.4 includes
the prohibited zone as well as the
critical zone.
ANCHORTYPE DISTANCE/ACTIONMetal expansion Anchor > 2 x depth of the failed hole
Chemical Anchor Fill up the failed hole
Plastic Anchor> 1 x depth of the failed hole and> 5 x diameter of the anchor
TAble 4.1 COMMONRULESFORDISTANCESBETWEENFAILEDHOLEANDNEWHOLE
PROHIBITED ZONE
CRITICAL ZONE
FREE ZONE
Ccr
Cmin
C2
C1
PICTURE4.3 Influenceofedgedistance
Scr S
S = Scr Scr > S > Smin
S < Smin
PICTURE4.4 Influenceofspacing
A)NOINFLUENCE B)REDUCTIONOFTHELOADNECESSARY
C)RISKOFCRACKING,INSTALLATIONPROHIBITED
1.4 INSTAllATION
SORMAT Technical manual 07/2008
1.4.5 INSTALLATION
CLASSIFICATIONS
There are three different modes
of installation, with respect to
anchoring technique. In pre-
installation (Picture 4.5a) the hole
will be marked, then drilled, the
anchor installed, the fixture fitted
and tightened. In this installation
method the hole of the fixture and
the drill hole of the anchor will be
different.
In through installation (Picture
4.5b) the fixture will be inserted
first into the right position,
through the hole of the fixture
drilled into the base material. The
anchor is then installed through
the fixture and tightened without
displacing the fixture in between.
This type of installation is used
often to fix heavy or complicated
structures or equipment. This
installation method minimizes the
possibility of fault drilling.
Distance installation, also called
stand-off installation, is used
mainly in facades (Picture 4.5c). In
this case the fixture is positioned
apart from the base material.
This is possible for anchors with a
thick maximum fixture thickness
or for threaded rods with female
thread anchors. In this installation
method anchors are subjected to
additional moment.
A)PRE-INSTALLATION B)THROUGHINSTALLATION C)DISTANCEINSTALLATION
PICTURE4.5 Installationmethods
1.4 INSTAllATION
SORMAT Technical manual 07/2008
SORMAT Technical manual 07/2008
1.5FASTENINGSYSTEMS
ANDMODEOFACTIONS
1.5.1MECHANICALANCHORS
1.5.1.1General
Mechanical anchors can be char-
acterized by transmitting the load
from the anchor to the concrete by
direct contact and are classified
according to their physical prin-
ciples to transfer loads from the
anchor into the concrete (Picture
5.1).
1.5.1.2 ExpansionAnchors
expansion anchors produce
wedge forces and frictional forces
in the base material. With torque
controlled expansion anchors,
a specified installation torque
is applied, with cone or cones is
drawn into the expanding sleeve
segments. Due to the pretension
in the anchor rod or to an external
tensile load, the torque controlled
anchors expand further, however
only if the friction between the
cone and the sleeves is smaller
than between the sleeves and
the concrete. Torque controlled
anchors are mainly used for
group and single fastenings in the
medium and high load ranges.
Displacement controlled anchors
are expanded by driving the cone
into the sleeve (drop-in anchor) or
the sleeve over the cone (out-cone
anchor). These anchors are mainly
used for multiple fastenings in the
medium and low load range.
1.5.1.2.1 Torquesettinganchors
When torque is applied to the bolt
head or the nut of the anchor, the
cone is drawn up into the sleeve
to expand its effective diameter.
The reaction of the concrete to
the expanded sleeve of the anchor
creates a high friction force be-
tween the anchor and the wall of
the drilled hole (Picture 5.2).
Applied tensile loads are resisted
by the following elements:
The anchor bolt or stud.•
The wedge action of the steel •
cone in the sleeve.
Friction between the expanded •
sleeve and the drilled hole.
Shear and tension at the surface •
of the potential concrete cone.
1.5.1.2.2 Displacementsetting
anchors
The anchor is inserted into a
drilled hole and set by displacing
the expander plug (Picture 5.3).
Applied tensile loads are resisted
by the following elements:
The fixing element (bolt, stud…)•
The steel body of the anchor•
Friction between the expanded •
anchor and the drilled hole.
Shear and tension at the surface •
of the potential concrete cone.
PICTURE5.1 Classificationofmechanicalanchors
PICTURE5.2 Torquesettinganchor
PICTURE5.3 Displacementsettinganchor
1.5 FASTeNING SYSTeMS AND MODe OF ACTIONS
FRICTION UNDERCUT UNDERCUT+FRICTION
DROP-INANCHOR THROUGHBOLT SHIELDANCHOR UNDERCUTANCHORS SCREWANCHOR
NOFURTHEREXPANSION FURTHEREXPANSION
BACKTOMAINMENU
SORMAT Technical manual 07/2008
1.5.1.3 Screwanchors
(Concretescrews)
The thread of the screw anchor
cuts into the concrete, transmit-
ting tensile loads by a threaded
undercut into the wall of the drill
hole (Picture 5.4). Friction avoids
the loosening and unscrewing of
the screw. The working principle
is a mixture of undercut anchors
and chemical anchors. The work-
ing principle can also be associ-
ated with the working principle of
the reinforcement bar. Concrete
screws are used normally for
medium loads.
Applied tensile loads are resisted
by the following elements:
The body of the anchor•
The thread cuts into the base •
material
The local compression strength •
of concrete in the location of the
thread
Shear and tension at the surface •
of the potential concrete cone
1.5.1.4 Undercutanchors
Undercut anchors are anchors
with parts that spread and me-
chanically interlock with the con-
crete base material. Much lower
expansion forces are produced
during installation and loading
than with expansion anchors. If
the shape of the undercut is well
adapted and its depth is sufficient,
an undercut anchor funktions vir-
tually identically to cast-in fixings,
i.e. both achieve the same ulti-
mate loads, because the undercut
anchor optimally uses the high
resistance to compression forces
of the concrete. Undercut anchors
are used to fix medium and high
loads with an excellent reliability.
1.5.1.4.1 Undercutanchor
With the use of the undercut-
ting tool, the conical shape of the
anchor fits into the conical cut of
the hole, developing the tensile
capacity of the bolt without any
slip or concrete failure (Picture
5.5). The undercut anchor works
like a cast-in anchor.
Applied tensile loads are resisted
by the following elements:
The stud•
The steel annulus, which fits •
into the conical cut
Shear and tension at the surface •
of the potential concrete cone
1.5.1.4.2 Selfcutting
undercutanchor
The anchor cuts into the concrete
by turning the nut (Picture 5.6).
Self-cutting anchors have at least
1,5 to 2 times higher resistances
than expansion anchors in general.
Applied tensile loads are resisted
by the following elements:
The stud•
The cutting action into the •
concrete
Shear and tension at the surface •
of the potential concrete cone.
1.5.1.5 Workingprinciplesofme-
chanicalanchors
Anchors used in walls and on
floors are generally subjected
to shear or combined shear and
tensile loads. One of the few appli-
cations where anchors are sub-
mitted to pure tensile load is the
suspension of ceilings. Although
most of the anchors are sub-
jected to shear loads; the shear
resistance is mainly influenced
by the substrate. edge distances
and the quality of the substrate
more strongly influence the shear
behaviour than the tensile resis-
tance of the anchor. Furthermore,
to introduce the shear load into
the substrate, only the rod and,
if available, the sleeve with the
rod are relevant. The real anchor
mechanism, normally placed
deeply in the hole, only prevent
the anchor from slipping out at
further displacements.
PICTURE5.4 Screwanchors
PICTURE5.5 Undercutanchor
PICTURE5.6 Self-cuttingundercuttinganchor
1.5 FASTeNING SYSTeMS AND MODe OF ACTIONS
SORMAT Technical manual 07/2008
1.5.1.6 Behaviourofmechanical
anchorsincrackedconcrete
In those areas where a concrete
member is under tensile stress,
the concrete is usually loaded over
its tensile capacity and the cracks
most often run through the anchor
holes. Drop-in anchors lose about
50 % of their bearing capacity in
a crack of 0,3 mm width, and the
capacity of torque controlled an-
chors is reduced 30 % of the value
attained in non-cracked concrete.
Some anchoring systems, which
are not approved for cracked con-
crete, can lose 90 % of their capac-
ity in cracked concrete (Picture 5.7).
Undercut anchors with sufficient
undercut depth may also be used
up to their full steel tensile capac-
ity in cracked concrete. The great
advantage of undercut anchors,
intelligently designed for steel
failure, is that the concrete quality
and the tensile or compression
zone need not be considered in
calculations. However, the de-
tailing rules concerning edge
distances and spacing must be
complied with.
If it is not proven in each case
that under a service condition the
anchor with its entire anchorage
depth is located in non-cracked
concrete, it must be assumed
that the installation will follow in
cracked concrete. (eTAG 001 An-
nex C, Paragraph 4.1)
The above-mentioned case covers
a large number of installations
into concrete. (Note! economical
design of concrete structures.)
1.5.2 CHEMICALANCHORS
1.5.2.1 General
Chemical anchors are character-
ized by the use of a bonding agent
fixing the anchor to the concrete
and are detailed by the applica-
tion method and the chemical
ingredients of the adhesive. The
usual application methods are the
capsule and the injection systems.
The ingredients are divided into
organic and inorganic compounds.
1.5.2.2 Workingprinciplesof
chemicalanchors
Similar to the mechanical anchors
the shear behaviour of the chemi-
cal anchors is mainly influenced
by the base material and the rod.
The mortar provides a very good
behaviour for dynamic loads by
filling the gap between anchor and
substrate completely and pre-
vents the system from displace-
ment. Therefore further expla-
nations focus only on the tensile
loads.
1.5.2.2.1 Chemicalanchors
The mortar penetrates the pores
and irregularities of the base ma-
terial and forms a key around the
threads of the stud. Cured mor-
tar transfers load onto the base
material via a mechanical and
adhesive bond (Picture 5.8).
Applied tensile loads are resisted
by the following elements:
The stud•
The bond between the stud and •
the mortar shear in the mortar
bond between the mortar and
the concrete.
Shear and tension in the con-•
crete.
TENSION LOAD
NON-CRACKED CRACKED CRACKED
100%
70%
NOT CRACK APPROVED ANCHOR
CRACK APPROVED ANCHOR
PICTURE5.7 Loadbearingcapacityofanchorsinnon-crackedandcrackedconcrete
PICTURE5.8 Thechemicalanchor
1.5 FASTeNING SYSTeMS AND MODe OF ACTIONS
SORMAT Technical manual 07/2008
1.5.2.2.2 Designofchemical
anchorsfortensileloads
In adhesive anchors different
failure modes can be observed
(Picture 5.9). If the embedment
depth is small, usually a concrete
cone is pulled out. If the embed-
ment depth is deeper, a combined
failure including a shallow con-
crete cone with bond failure below
the cone is typically observed.
The bond failure can be at the
adhesive / concrete interface or
the anchor / adhesive interface or
a mixture of both. If the embed-
ment depth is deep enough, this
may lead to the steel failure in the
anchor. The minimum depth for
steel failure represents the basic
development length of the anchor,
which depends on the steel qual-
ity, the properties of the bonding
agent and the concrete quality.
The bond strength is dependent
on the type of the resin as well the
producer. The given bond strength
is valid only for an appropriate
product. Furthermore the com-
pression strength of the concrete
affects to the bonding. Gener-
ally, resin, approved for concrete
C20/25, can be used up to con-
crete strength C50/60. If the resin
is used for high strength concrete,
> C50/60, the bond strength may
decrease because of the smooth
surface of the bore hole. Given
values are valid typically both in
dry concrete and in hammer drilled
holes. The holes have to be cleaned
properly with an air pump and brush
and the instruction of the manufac-
turer also has to be followed, e.g.
the temperature and curing times
has to be complied with.
The cleanliness of the bore hole is
one of the most important things
to remember in installing chemi-
cal anchors. Depending on the
chemical anchoring system, the
load-displacement features can
dramatically degenerate. Glass
capsule systems are less
vulnerable because broken glass
and the ingredients of the capsule
clean the wall of the hole as a
result of the installation. As a rule
of thumb, the decrease of the bond
strength is ≤ 20 %.
With respect to injection resin
systems, is the bond strength
directly depends on the remaining
dust on the wall of the bore hole.
High quality resins are less sensi-
tive to the dust, but the decrease in
bond strength could be up to 60 %
(Picture 5.10).
PICTURE5.9 Differentfailuremodesofthechemicalanchorundertensionload
CONCRETE RESIN/CONCRETE ANCHOR/RESIN ANCHOR/RESINANDRESIN/ANCHOR
STEEL
TENSION LOAD
1 2 3 4
PICTURE5.10 Impactofintensityofcleaning
1 2XAIRPUMP 2XBRUSH 2XAIRPUMP
2 1XAIRPUMP 1XBRUSH 1XAIRPUMP
3 2XAIRPUMP
4 NOCLEANING
1.5 FASTeNING SYSTeMS AND MODe OF ACTIONS
SORMAT Technical manual 07/2008
1.5.2.2.3 Behaviourofchemical
anchorsincrackedconcrete
To introduce the load introduc-
tion into substrate, it is neces-
sary to transfer the load from
the rod into the mortar and from
the mortar into the substrate.
The load transfer into the mortar
for anchors suitable in cracks
is normally achieved by a rod
with cones. The cones can be
described as an undercut in the
mortar. The size of the cone has
to be sufficient to transfer the
load in cracks up to 0,3 mm. The
roughness of the substrate is not
sufficient to transfer the load, if
the crack crosses the joint (Pic-
ture 5.11a). Therefore the aim is
to create the crack through the
mortar (Picture 5.11b). To prevent
detaching the mortar from the
substrate,s sometimes a coating
of the rod is used. It is evident that
also with coned rods, cracks open
first in the boundary surface of the
concrete and resin. However after
an increase in loading, cracks will
run through the mortar.
A)THREADEDROD B)SPECIALRODWITHCONES
PICTURE5.11 Pathofthecrack
1.5 FASTeNING SYSTeMS AND MODe OF ACTIONS
SORMAT Technical manual 07/2008
SORMAT Technical manual 07/2008
1.6 OTHERASPECTS
1.6.1 SAFETYOFTHEANCHORAGE
Safety is the most important
aspect of construction. Therefore,
the so-called safety factor con-
cept has been created to compen-
sate for possible human errors or
irregularities in the material. The
safety factors for base materials,
anchor types, and failure modes
are given in valid approvals. Ap-
provals also include characteristic
loads ensured by several tests. A
permissible load is only a fraction
of the break load and that’s why
the variation of the base material,
installation errors and changes in
loading are taken into account.
Anchorage with high safety
requirements always requires
an engineering-based design,
including verifiable calculations
and construction drawings. There
are actually two different safety
factor methods available the
global safety factor method and
the partial safety factor method.
The partial safety factor is more
flexible and has broader utilization
possibilities, because it takes into
account the variation and ambigu-
ity of material or loads (dead load
and live load) as well as installa-
tion risks more effectively than
the global safety factor method.
In the fire design of anchors,
safety factors are considered
differently otherwise, it would
be impossible to reach adequate
results in anchor designing. The
safety factor for the action is
normally ≥ 1, but the resistance of
the anchor should conform to the
approval. In some cases reducing
the resistance may be necessary
for carbon steels to achieve the
desired fire rating.
Picture 6.1 shows the basic idea
of the global safety factor method
and picture 6.2 illustrates the idea
of the partial safety factor meth-
od. Pictures 6.3 and 6.4 exhibits
some special terminology used in
anchor design. The maximum load
shows the highest achieved load
in a test. The average value shows
the average of all measured maxi-
mum loads in a test. 5 %-fractile
is a statistics value, indicating that
only 5 % of the single values with
certain probability i.e. 90 %, are
below this value. The characteris-
tic resistance is the 5 % -fractile
of maximum loads of each failure
mode and load direction. The
design value for the resistance is
a characteristics resistance di-
vided with relevant safety factors
of material and installation. The
permissible load is the maximum
allowble load value in service
conditions
LOAD
MAX. LOAD
DISPLACEMENTPICTURE6.3 Load-displacementcurvewithamaximumload
1.6 OTHeR ASPeCTS
F5%(CHARACTERISTICSVALUE) FR=(F5%/Y)(PERMISSIBLELOAD)
PICTURE6.1 Globalsafetyfactormethod
CHARACTERISTICSVALUE DESIGNVALUE
RESISTANCE Rk Rd=Rk/YMRd≥Sd
ACTION Sk SD=SK*YF
PICTURE6.2 Partialsafetyfactormethod
BACKTOMAINMENU
SORMAT Technical manual 07/2008
1.6.2FIRERESISTANCE
OFTHEANCHORS
1.6.2.1 TemperatureCurves
Picture 6.5 shows the actual valid
temperature-time-assumptions
on which the fire tests for anchors
are based. The significant point of
the tunnel temperature curves is
the inordinately rapid increase of
the temperature over 1 000 ºC.
1.6.2.2 FireImpactonAnchors
It is customary, that electrome-
chanical installations, plumbing,
and false ceilings are fixed by an-
chors. These anchors guarantee
the safe access of the emergency
crews for the design fire load. The
anchors have to be designed to
withstand the impact of the rel-
evant temperature/time curve, i.e.
the emergency crews should not
be exposed to falling debris.
Anchors have been exposed to fire
tests under different fire curves
,for example, at the German
Institute IbMb of the Technical
University of brunswick, Germany.
Tensile loads of anchors made
of normal steel and of high-cor-
rosion resistant steel eN 1.4529
in cracks of 0,2 mm and direct
fire impact without protection of
the anchor have been tested. The
tests have shown the following
results:
At high temperatures, the base •
material breaks down (spalling
of concrete). The damaged area
increases with the duration of
the fire according to the tem-
perature exposure. Setting an
anchor deeper therefore, helps
to keep the anchor intact in a
concrete substrate.
Although metal does not burn, •
its loading capacity decreases
with increasing temperature
(especially from about 500 ºC
upwards). This is shown during
the fire test by slipping nuts or
breaking of anchor rods.
As the temperature increases, •
the loading capacity of the
base material and the anchor
decreases. The conclusion is
that the load must be reduced
below the level of the normal
recommended load necessary
for ordinary steel to achieve the
desired fire rating.
Fire tests have proven that the be-
haviour of stainless steel is better
than that of normal carbon steel.
Generally, it can be stated that the
tensile fire loads of stainless steel
are double that of carbon steel.
PICTURE6.4 Relativefrequencyofloads
1.6 OTHeR ASPeCTS
RELATIVE FREQUENCE
LOAD F
AVERAGE5%-FRACTILE
SORMAT Technical manual 07/2008
PICTURE6.5 Temperaturecurves
FireinMontBlanctunnel24.3.1999
1.6 OTHeR ASPeCTS
SORMAT Technical manual 07/2008