SIST-TP CEN/TR 15728:2008

SLOVENSKI STANDARD
01-oktober-2008
Dimenzioniranje in uporaba transportnih sider za betonske polizdelke - Elementi
Design and Use of Inserts for Lifting and Handling of Precast Concrete - Elements
Bemessung und Verwendung von Transportankern für Betonfertigteile
Conception et utilisation d'inserts pour le levage et la manutention du béton préfabriqué -
Éléments
Ta slovenski standard je istoveten z: CEN/TR 15728:2008
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 15728
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2008
ICS 91.100.30
English Version
Design and Use of Inserts for Lifting and Handling of Precast
Concrete - Elements
Conception et utilisation d'inserts pour le levage et la Bemessung und Verwendung von Transportankern für
manutention du béton préfabriqué - Éléments Betonfertigteile
This Technical Report was approved by CEN on 2 March 2008. It has been drawn up by the Technical Committee CEN/TC 229.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15728:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
1 Scope .4
1.1 Scope / General.4
1.2 Types of inserts for lifting and handling .4
1.3 Minimum dimensions .4
2 Normative references .5
3 Definitions and symbols .5
3.1 Definitions .5
3.2 Symbols .7
4 General design principles.8
4.1 General principles.8
4.2 Partial factors.8
5 Actions on inserts.9
5.1 Actions.9
5.2 Effect of lifting procedures on load directions.9
5.3 Actions from adhesion and form friction .11
5.4 Dynamic actions .12
6 Choice of inserts.12
7 Use of Supplier’s recommendations .13
8 Use of CEN/TC 229 recommendations for typical user situations .14
8.1 General conditions .14
8.2 Types of inserts covered .17
8.3 Lifting of walls and linear elements.21
8.4 Lifting of slabs and pipes .32
9 Precaster use of testing .36
10 Recommended technical documentation .36
10.1 General.36
10.2 Properties of inserts.36
10.3 Design of specific lifting application .37
11 Lifting and handling instructions.37
Annex A (informative) Provisions for testing of inserts for specific lifting and handling situations .39
Annex B (informative) Information to be given by the insert supplier.48
Bibliography .51

Foreword
This document (CEN/TR 15728:2008) has been prepared by Technical Committee CEN/TC 229 “Precast concrete
products”, the secretariat of which is held by AFNOR.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
To ensure the performance of the precast concrete products, lifting and handling should be taken into account in
the design of the product.
Inserts are used for lifting and handling of precast elements. They should meet an appropriate degree of reliability.
They should sustain all actions and influences likely to occur during execution and use.
This Technical Report deals with all lifting inserts cast into precast concrete elements i.e. lifting parts developed
and produced at the precasting plant as well as lifting inserts as part of a system supplied by a manufacturer of
lifting systems. The intent of this document is to give information to precast product designers.
The failure of inserts for lifting and handling could cause risk to human life and/or lead to considerable economic
consequences. Therefore inserts for lifting and handling should be selected and installed properly by skilled
personnel.
This Technical Report based on current practices gives recommendations for correct choice and design of lifting
inserts according to the lifting capacity of their part embedded in the concrete. It is based on EN 1992-1-1
(Eurocode 2) and on published supplier’s data.
In the Technical Report numerical values for partial safety factors are recommended as basic values that provide
an acceptable level of reliability. They have been selected assuming that an appropriate level of workmanship and
of quality management (Factory Production Control) applies. They may be applied in the absence of national
regulations.
1 Scope
1.1 Scope / General
This Technical Report provides recommendations for the choice and use of cast-in steel lifting inserts, hereafter
called 'inserts' for the handling of precast concrete elements. They are intended for use only during transient
situations for lifting and handling, and not for the service life of the structure. The choice of insert is made according
to the lifting capacity of their part embedded in the concrete, or may be limited by the capacity of the insert itself
and the corresponding key declared by the insert manufacturer. The report covers commonly used applications
(walls/beams/columns and solid slabs and pipes) and the range of these applications is further limited to prevent
other types of failure than concrete breakout failure (cone failure), failure of supplementary reinforcement or failure
in the steel insert. A basic supposition is that the concrete is demonstrably uncracked during all lifting situations.
The limitation in scope is used to obtain simple design models. Further information may be found in [1].
The recommended safety levels are intended for short-term-handling and transient situations.
This Technical Report applies only to precast concrete elements made of normal weight concrete and
manufactured in a factory environment and under a factory production control (FPC) system (in accordance with
EN 13369:2004, clause 6.3) covering the insert embedment.
This Technical Report does not cover :
 The design of the insert itself (for inserts manufactured by insert suppliers).
 The lifting key that hooks on to the embedded lifting insert as a component between the insert and the lifting
machinery (crane, excavator…), nor its compliance with the embedded insert. These components, when
brought to the market separately, are covered by the Machinery Directive (98/37/EC).
 Lifting inserts for permanent and repeated use.
This report is not an interpretation of the Machinery Directive.
1.2 Types of inserts for lifting and handling
This Technical Report applies to the embedment of lifting inserts made by the precaster for his own use as well as
lifting inserts forming part of lifting systems brought to the market by a lifting system supplier, see tables 8.3 and
8.6. Devices made by the precaster may consist of smooth bars, prestressing strands and steel wire ropes. The
system devices may be e.g. internal threaded inserts, flat steel inserts and headed inserts.
Lifting loops of ribbed bars are not covered, nor wire ropes of less than 6 mm.
1.3 Minimum dimensions
This Technical Report applies in general to inserts with a minimum nominal diameter of 6 mm or the corresponding
cross section. In general, the minimum anchorage depth should be l = 40 mm.
a
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
EN 1990:2002, Eurocode — Basis of structural design.
EN 1992-1-1:2004, Eurocode 2: Design of concrete structures – Part 1-1 : General rules and rules for buildings.
EN 10025-2:2004, Hot rolled products of structural steels – Part 2: Technical delivery conditions for non-alloy
structural steels.
)
EN 10138-3, Prestressing steels — Part 3 : Strand .
EN 12385-4:2002, Steel wire ropes — Safety — Part 4 : Stranded ropes for general lifting applications.
EN 13369:2004, Common rules for precast concrete products.
EN 13414-1:2003, Steel wire rope slings — Safety — Part 1 : Slings for general lifting service.
CEN/TR 14862:2004, Precast concrete products — Full-scale testing requirements in standards on precast
concrete products.
3 Definitions and symbols
For the purposes of this document, the following terms, definitions and symbols apply.
3.1 Definitions
3.1.1
concrete breakout failure
concrete cone separated from the base material by loading the insert
3.1.2
concrete breakout resistance
the resistance corresponding to a concrete cone surrounding the insert or group of inserts separating from the
member
3.1.3
edge distance
the distance from the edge of the concrete surface to the centre of the nearest insert

)
Presently under preparation
3.1.4
anchorage length
for cast-in headed insert bolts and splayed inserts, the anchorage length, l , is illustrated in Figure 1
a
l = 1,25(L+ s− a)≤ L+ s l = 1,25(L+ s− a)≤ 0,85L+ s
a a
Figure 1 — Examples of anchorage length for different types of inserts
3.1.5
embedment depth
distance from the concrete surface to the farthest point of insert, measured perpendicular to the concrete surface
3.1.6
factory Production Control (FPC)
a quality system satisfying the requirements in EN 13369, clause 6.3
3.1.7
headed insert
a steel insert with a head for anchorage installed before placing concrete
3.1.8
insert
a steel unit cast into concrete and used for lifting of precast elements
3.1.9
insert loading
axial, shear or combined - Loads applied to the insert
3.1.10
insert resistance
load capacity (characteristic value) of the part of the insert embedded in the concrete (different from maximum
working load of the insert – see 3.1.13). In this report, the wording “characteristic resistance” is sometimes used
3.1.11
lifting key
lifting tool to couple to the embedded insert
3.1.12
lifting system
system of lifting key and appropriate insert
3.1.13
maximum working load
maximum load guaranteed by the supplier before steel failure, reduced by application of the relevant safety
coefficient and marked on a lifting key or system (from Directive 98/37/EC, 4.1.1)
3.1.14
precaster
producer of precast concrete elements in a factory environment
3.1.15
pullout failure
a failure mode in which the insert pulls out of the concrete without a steel failure and without a concrete breakout
failure
3.1.16
side-face blow-out resistance
the resistance of inserts with deeper embedment but thinner side cover corresponding to concrete spalling on the
side face around the embedded head while no major breakout occurs at the top concrete surface
3.1.17
insert steel failure
failure mode characterised by fracture of one of the steel insert parts
3.1.18
minimum reinforcement
reinforcement required by EN 1992-1-1 or in national annex (Nationally Determined Parameter)
3.1.19
supplementary reinforcement
reinforcement designed to resist the full load in case of a concrete failure
3.1.20
complementary reinforcement
reinforcement provided to avoid brittle failure
3.1.21
supplier
manufacturer of lifting inserts brought to the market or its authorized distributor
3.2 Symbols
3.2.1 Action and resistance
E design value of actions acting on a single insert
d
N characteristic value of resistance of a single insert
Rk
N design value of resistance of a single insert
Rd
q adhesion
adh
ψ dynamic coefficient
dyn
γ partial factor for dead load
G
γ partial factor for live load
Q
γ partial factor for concrete
c
γ partial factor for steel
s
3.2.2 Concrete and steel
f characteristic compressive strength of concrete (strength class) measured on cylinders
ck
(150 x 300) mm
f characteristic steel yield strength or steel proof strength respectively
yk
f characteristic steel ultimate tensile strength
uk
A stressed cross section of steel
s
3.2.3 Inserts
Notation and symbols frequently used in this technical report are given below. Further particular notation and
symbols are given in the text.
c edge distance from the axis of an insert
d diameter of insert bolt or thread diameter
d diameter of insert head (headed inserts)
h
d diameter of reinforcing bar
s
l anchorage length (Figure 1)
a
4 General design principles
4.1 General principles
The inserts load capacity for lifting and handling should be calculated and/or tested according to the principles and
design models given in this document. Embedment conditions for lifting and handling, which do not conform to
these principles or design models, should be tested according to the recommendations given in Annex A and
evaluated in accordance with EN 1990.
Actions should be obtained from the relevant parts of EN 1991-1 where applicable.
4.2 Partial factors
4.2.1 Partial factors for actions
In the absence of National provisions the following factors are recommended:
γ = 1,15 (partial factor for dead load) ;
G
γ = 1,5 (partial factor for live load, i.e. adhesion, friction and dynamic actions).
Q
4.2.2 Partial factors for resistance
In the absence of National provisions the partial factors given in Tables 1 and 2 are recommended.
Recommended values of the partial factors γ for characteristic resistance of steel based on characteristic ultimate
s
values (R , f ) are given in Table 1. For solid steel loops, steel wire ropes and prestressing strands the partial
uk uk
factor γ is based on the characteristic resistance of the loop including effects of the lifting hook.
s
Recommended values of the partial factor γ for failures in the load transfer between the insert and the concrete
c
are given in Table 2. These values assume that an FPC system is used to control that concrete is uncracked in the
vicinity of the insert.
Table 1 — Partial factors γγγγ for steel failure
s
Type of insert
f ≤ 800N / mm² and f / f ≤ 0.8 f > 800N / mm² or f / f > 0.8
uk yk uk uk yk uk
Solid steel lifting systems Max(1,5; 1,2 f /f ) 1,7
uk yk
*)
Solid steel (smooth bars) lifting loops 2,0 -
Steel wire ropes - 1,8
Prestressing strands - 1,8
*)
The material for smooth bar lifting loops should be at least equivalent to S235J2+N.
Table 2 — Partial factors γγ for concrete failure
γγ
c
Loading in Certified FPC
Tension 1,5
Shear, combined tension and shear 1,5
5 Actions on inserts
5.1 Actions
The forces acting on an insert should be calculated for all relevant loading situations taking into account the product
properties, the position of the inserts, condition of the form, lifting equipment, number and length of the ropes,
chains or straps and the static system. In some cases it might be necessary to take into account the deformations
of the precast element during lifting and handling.
5.2 Effect of lifting procedures on load directions
Inserts for lifting and handling may be subjected to loads acting in different directions during operation. As
examples information on slabs and wall elements are given.
The lifting equipment should allow statically determinate load distribution to the inserts (see Figure 2). To ensure
that all inserts carry their required part of the load, sliding or rolling couplings between the lifting wires or chains
should be used when there are more than two lifting points. In a statically indeterminate system the load distribution
on the inserts depends in most cases on the unknown stiffness of the ropes and the position of the insert
(see Figure 3). Therefore only the statically determinate part of a system should be used in calculating the actions
on the inserts.
a) b)
Figure 2 — Examples of handling equipment for slabs

Figure 3 — Statically indeterminate system, only two inserts loaded

Figure 4 — Example of statically determinate lifting of a slab and resolution of forces
Depending on the equipment used during lifting the inserts may be subjected to combined parallel and transverse
shear load (Figure 5a), combined tension and parallel shear loads (Figure 5b), transverse shear loads (Figure 5c)
or axial tensile loads (Figure 5d).

a) b) c) d)
Key
a) Combined parallel and transverse shear load
b) Combined tension and parallel shear load
c) Transverse shear load
d) Axial load
Figure 5 — Examples of loads on lifting inserts for walls
Shear loads acting on inserts may be assumed to act without a lever arm, if the design of the inserts and its key
avoids significant concrete crushing in front of the insert during loading. If this condition is not satisfied the lever
arm should be taken as the actual distance between the shear force and the concrete surface plus half the nominal
diameter of the insert.
5.3 Actions from adhesion and form friction
Adhesion and form friction will occur when the precast element is removed from the formwork. The values should
be taken from National provisions. In the absence of National provisions the values for the combined effect of
adhesion and form friction q given in Table 3 may be considered. General values for form friction are difficult to
adh
assess and friction should be avoided as far as possible.
For some types of uneven form surfaces (structured matrixes, reliefs, structured timber etc.) the forces may be
much larger than given in the table, and should be considered separately. The forces may be zero if the concrete
does not come in contact with the form at all, for example if the concrete is poured on a layer of bricks that has
been laid out on the form bottom. Large vertical form surfaces may create extensive friction forces due to
undulations in the form. Prestressed components will usually have a camber caused by the prestressing force, and
will therefore have lower friction against the vertical sides of the form.
Table 3 — Examples of values of q
adh
*)
Formwork and condition
q
adh
Oiled steel mould, oiled plastic coated plywood 1 kN/m
Varnished wooden mould with planed boards 2 kN/m
Oiled rough wooden mould 3 kN/m
*)
The area to be used in the calculations is the total contact area between the concrete
and the form.
The actions, E , for demoulding situations should be determined from:
d
E =γ ⋅ G+γ ⋅ q ⋅ A
d G Q adh f
with
G = weight of the precast concrete element ;
A = form area in contact with concrete ;
f
γ and γ are partial safety factors for permanent and variable actions respectively.
G Q
5.4 Dynamic actions
During lifting and handling the precast elements and the lifting devices are subjected to dynamic actions. The
magnitude of the dynamic actions depends on the type of lifting machinery. Dynamic effects should be taken into
account by the dynamic coefficient ψ given in National regulations. In the absence of National Regulations the
dyn
values of Table 4 may be considered. Other dynamic influences than covered by Table 4 should be based on
special provisions or engineering judgement.
Table 4 — Influence of dynamic actions on site
Dynamic influences Dynamic coefficient (ψ )
dyn
x)
Tower crane and portal crane 1,2
x)
Mobile crane 1,4
Lifting and moving on flat terrain 2 – 2,5
Lifting and moving on rough terrain 3 – 4

x)
In precasting factories and if special provisions are made at the building site
lower values may be appropriate.
The actions, E , for lifting situations should be determined from Equation (5.3):
d
E =γ ⋅ G+( ψ − 1)γ ⋅ G
d G dyn Q
6 Choice of inserts
Having determined the actions on the insert for all relevant load combinations the task remains to choose an
appropriate insert and relevant reinforcement.
The insert load capacity depends on the field of application. The designer has three options in choosing the
appropriate lifting arrangement :
1) The recommendations given by the insert suppliers may be used directly. This option is further described
in clause 7;
2) The design charts provided in clause 8 may be used;
3) Tests may be carried out specific to the intended application as outlined in clause 9.
Figure 6 indicates which option could be appropriate in a given situation.
7 Use of Supplier’s recommendations
The commercially available lifting systems are usually designed and optimised for defined fields of application, in
some cases based on results from proprietary test programs. Catalogue material from the supplier often describes
corresponding design methods. These methods may be used provided that one of the following conditions is
satisfied :
1) The method is certified by an accredited third party in accordance with a relevant ETAG;
2) The method is certified by an accredited third party in accordance with a CEN product standard;
3) The method is certified by an accredited third party based on tests according to Annex A;
4) The method is given by national provisions.
The supplier’s declaration of the product should state the method chosen. If the supplier cannot satisfy either of
these conditions, or if the intended application falls outside the range of validity for the design methods
recommended by the supplier, the designer should choose one of the options in clause 8 or clause 9.
Information given by the supplier should conform to Annex B.
NOTE Suppliers’ catalogues may disclaim the responsibility for the use of the data. Consequently, such catalogues should
not be used as a recommendation.
Key
1)
The application of the insert is fully within the limits stated in the catalogue of an insert supplier or manufacturer. These
limits include weight, concrete strength, edge distance, dimensions of the concrete member, local reinforcement and mode of
lifting.
2)
To verify the design model of chapter 8 for a certain type of insert it might be necessary to perform tests according to Annex
A. The reinforcement provided to transfer loads from the insert into the element should be designed according to National
provisions. Reinforcement for other purposes such as flexural or shear capacity of the precast element in use would not
normally be considered in this.
3)
Specific testing is intended to justify the capacity in a particular situation. As an example, this might include inserts for tunnel
segments or bridge beams. It does not provide information for a wide range of applications.
Figure 6 — Flow chart for the design of lifting inserts
8 Use of CEN/TC 229 recommendations for typical user situations
8.1 General conditions
For most common applications, present practice and available general information concerning the load capacity of
inserts can be combined into a design model. This model is described in further details in sections 8.3 – 8.4. The
model is not universally applicable. Limitations on the range of validity are used to exclude situations where other
types of failure than concrete breakout failure (cone failure), failure of supplementary reinforcement or steel failure
in the insert can occur. Within the indicated limited range of validity the model yields results that are very close to
present practice. The limitations on the range of applicability are the following:
1) Field of application
The most common fields of application are:
a) walls and other linear elements (such as beams and columns), where the insert is typically long
compared to the edge distance (the smallest distance from the insert to a concrete surface parallel to
the insert) and where the concrete in the vicinity of the insert is uncracked.
b) slabs and pipes, where the edge distance is large while the possible length of the insert is limited by
the thickness of the element and where the concrete in the vicinity of the insert is uncracked.
This section covers the use of some common types of inserts in these two situations, cp tables 7
and 10.
2) Reinforcement is provided in the region of the insert, either as complementary reinforcement or as
supplementary reinforcement.
Minimum reinforcement is typically provided according to EN 1992-1-1. Although provided for other
reasons the reinforcement may also act as a safeguard against failure in case cracking should
unexpectedly take place in the concrete around the insert. If minimum reinforcement is not provided
complementary reinforcement should be provided. If the minimum reinforcement is left out the risk of
accidental cracking and brittle failure might be unacceptable.
The presence of complementary reinforcement also makes it possible to postpone the development of a
breakout failure so that the capacity of the insert becomes somewhat larger than in unreinforced concrete,
see e.g. ref. [2].
Supplementary reinforcement is designed specifically to transfer the full load on the insert to the concrete
element as a whole. The suggested models for design of the supplementary reinforcement are in
accordance with the rules given in EN 1992-1-1.
3) Minimum characteristic strength of concrete.
Where no other indication of minimum concrete compressive strength is given, it is assumed that the
concrete strength (at the time of lifting) is at least 15 MPa measured on cubes, side length 150 mm
(or 12 MPa measured on cylinders).
4) Factory Production Control (FPC).
It is assumed that the precaster applies a Factory Production Control system according to the
requirements in EN 13369, clause 6. It is furthermore assumed that the inspection scheme for finished
product inspection includes a check that no harmful cracking has occurred in the neighbourhood of the
inserts at the time of delivery.
5) No extrapolation of design graphs.
The validity of the calculation model outside the range covered by the graphs is not sufficiently known and
therefore the graphs should not be extrapolated.
6) Safety factors.
To facilitate the use of nationally determined partial factors the capacity values given in this chapter could
be used as characteristic values.
Figure 7 — Type a) inserts. Headed bolts and spread
anchors
Headed bolts and spread anchors transfer axial load to
the concrete through mechanical interlock at the built-in
end while shear load is transferred more or less directly
between the recessed lifting key and the concrete at the
top end.
Figure 8 — Type b) inserts. Anchors with additional
rebar
These inserts maintain the possibility of shear transfer
directly from the lifting key to the concrete, while the
axial load is transferred to the concrete through a
separate reinforcement bar to be threaded into a hole in
the insert.
Figure 9 — Type c) inserts. Anchor systems with
threaded sockets
These inserts may utilize a simpler, threaded key to
transfer the load to the insert. The axial load is
transferred to the concrete through a bonded rebar
either in the form of a separate bar threaded into a hole
or as a built in rebar (e.g. waved anchors) included in

the system. The corresponding key may or may not be
suitable for transfer of shear forces.
Figure 10 — Type d) inserts
These inserts are short versions of type a) inserts –
possibly with an extended bearing area at the built-in
end of the insert. They are intended for use in slabs and
pipes to sustain axial load and shear load.

Figure 11 — Type e) inserts. Similar to type a)
Inserts intended for use in slabs and pipes with short
embedment lengths and large bearing areas that are
also suited for supporting the necessary minimum

reinforcement. Axial load as well as shear load may be
accommodated.
Figure 12 — Type f) inserts. Plate sockets
A threaded socket mounted on a plate providing a
bearing area for axial load. The corresponding keys are
usually not suited for transfer of shear, but special
options exist.
8.2 Types of inserts covered
8.2.1 Commercially available inserts
Many types of inserts are commercially available as illustrated in Figure 7 – 12.
All these standard lifting systems consist of an insert embedded in the concrete element and a matching unit (key)
that connects to the insert (Figure 7). The crane hook or hook of a lifting sling attaches to the key. The combination
of components from different systems is prohibited.
Threaded lifting devices and corresponding keys should be marked with a colour corresponding to their diameter.
The colours given in Table 5 are recommended.
Table 5 — Recommended colour identification codes of lifting systems for threaded lifting systems
Diameter Colour
Rd 12 orange
Rd 16 red
Rd 20 light-green
Rd 24 dark-grey
Rd 30 dark-green
Rd 36 light-blue
Rd 42 silver-grey
Rd 52 yellow
For other than threaded systems, the following method of marking is possible.
The marking consists of a System ID and an Insert ID (Table 6). It should be fixed directly to the cast-in part and
the lifting key.
Table 6 — Marking of insert and key
System ID Insert ID
Producer System Specification
Lifting key P S
Insert P S X
The System-ID consists of the identification of the producer P (minimum two letters or logo) and the producer’s
name for the system S.
In many cases different types of cast-in-inserts belong to the same system. Therefore the insert has to be marked
with an Insert-ID containing additional information such as the specification by the supplier X and the length of the
anchor Y. It should be visible after pouring the concrete. It is recommended to mark the insert directly with its length
or to use a length identification code (capital letter or colour).
8.2.2 Inserts made by the precaster
In addition to the commercially available inserts the precasters may produce their own lifting loops from smooth
bars, prestressing strands or steel wire ropes. Necessary information on the handling of the element, e.g. lifting
hook dimensions, shall be given in erection specifications.
Lifting loops should only be used if the lifting angle is approximately the same in all lifting and handling situations.
Furthermore, the lifting angle should be kept within the limits indicated in Figure 14.

Figure 13 — Lifting loops made of smooth bar, strand or steel wire rope (Type g) inserts)
Examples of the inserts are shown in Figure 13 and they should conform to the following specifications:
 Smooth bars
The material for smooth bar lifting loops should be at least equivalent to EN 10025-2, S235J2+N. During
operation the minimum bending diameter of the smooth bar should not be less than 5 bar diameters. The size
of the lifting hook may require a larger bending diameter.
 Strands
The shape of the strands may be adapted to the various types of elements. Prestressing strands that have
been deformed before shaping should not be used. Bending of the strands during stocking or turning of
elements should be avoided.
The bending diameter of the strand loop (illustrated by the curvature of the sleeve in Figure 13) should be
equal to or less than twice the diameter of the lifting hook (the diameter is 2⋅s in the figure in Table 8). The
bending diameter of the strand loop must be larger than the diameter of the lifting hook. The strand diameter
should not exceed 13 mm and the bending radius should be at least 50 mm.
Bundling of maximum four strands may be used only when provided with a steel sleeve bent together with the
strands, see Figure 13.
To take into account effects of lifting hook diameter and different load distribution to the strands within a
bundle, capacity reduction factors are given in Tables 8 and 9.
 Steel wire ropes
Only steel wire ropes, which comply with EN 12385-4 and 13414-1 should be used.
2 2
Steel and fibre cores are allowed. The rope grade should be 1770 N/mm or 1960 N/mm . However, in
calculations only a value of 1770 N/mm should be considered.
To ensure sufficient flexibility of a rope the steel wire ropes should consist at least of the following number of
wires:
d = 6 mm: 42 wires minimum
d ≤ 14 mm: 114 wires
d > 14 mm: 200 wires
The bending diameter of the steel wire rope should not be less than 2 rope diameters.
To ensure sufficient bond steel wire ropes must be cleaned. The ends of the lifting loop made of a steel wire
rope should be ferrule-secured or split. Split ends should not be taken into account in the design, but a
ferrule-secured end will provide some extra anchorage.
The loading angle, β, (angle between the direction of the force and the axis of the insert) should not exceed
30°, (see Figure 14). The effect from β on the distribution of the force to the legs of the loop should be
considered.
a)
b)
Figure 14 — Loading angle for lifting loops
Table 7 — Design summary for inserts under inclined tensile loading in walls and linear elements
Anchor type
b)
c)
a)
g)
Walls and linear elements
Basic steel capacity Choose an insert with sufficient steel Choose an insert and associated rebar both Choose an insert with sufficient steel Choose an insert with sufficient steel
resistance based on supplier declaration with sufficient steel resistance based on resistance based on supplier declaration resistance based on supplier
supplier declaration, see Figure 21 declaration
Wall thickness Prevent blow-out failure by using Figure 16 Ensure that wall thickness is sufficient to obtain normal anchorage conditions: wall thickness larger than 7 times bar diameter
(straight bars) or 11 times bar diameter (other than straight bars). If smaller thickness: the embedment length shall be increased.
Amount of complementary
Prevent brittle failure due to concrete cracking, see Figure 17
reinforcement
Anchorage Anchorage length,
see Figure 1
Anchorage length for axial load Determine required anchorage length Determine required anchorage length for Determine required anchorage length for Determine required anchorage length
corresponding to concrete cone capacity bent rebar, see Figure 22. hooked rebar, Figure 22. Check that for strand or hooked bar, Figure 22.
from Figure 18. necessary anchorage length determined
from Figure17issmaller
Supplementary hairpin If concrete cone capacity is too small or if None for tension None for tension None for tension
reinforcement (replaces shear load component: determine required
complementary reinforcement) reinforcement to carry the whole anchor
load, see Figure 19, 20 and 22
Supplementary diagonal pull Choose reinforcement arrangement and Choose reinforcement arrangement and Choose reinforcement arrangement and Not used. Insert to be tilted according
reinforcement, see Figure 23 amount amount amount to load direction
0 0 0 0 0 0 0
Capacity reduction due to shear 20% for loading angle 30 <β<60 20% for loading angle 30 <β<60 30% for loading angle 30 <β<45 Loading angle β < 30
in wall plane provided suitable key 15% per 10 loading angle
Supplementary tilting Choose reinforcement arrangement and amount, see Figure 24
reinforcement for transversal
shear
Capacity reduction due to To be tested
transversal shear
8.3 Lifting of walls and linear elements
The choice of an appropriate insert for a wall application would typically involve:
 Selection of an insert, suitable for the load direction and with sufficient resistance of the insert itself;
 Checking that the concrete wall thickness is sufficient;
 Checking that the available reinforcement can prevent brittle failure;
 Determination of the required anchorage length for the insert;
 Checking the need for supplementary reinforcement around the insert;
 Compensation for the possible reduction in capacity due to shear load component.
These items are summarised in Table 7 and further dealt with in the following sections.
8.3.1 Basic steel capacity
All commercially available inserts should be marketed together with a declaration stating the expected
characteristic resistance of the insert corresponding to a failure in the steel. The value should cover the transfer of
load from the key or lifting hook to the insert and any type of possible failure within the insert itself (e.g. welding).
The value may be given as a combination of the maximum working load and a safety factor.
For type g) inserts (usually produced by the precaster) the precaster should evaluate the available characteristic
resistance with due respect to the key or lifting hook to be used. An estimate can be made by ordinary vectorial
addition of the resistance in the two legs.
For lifting loops made of strands the influence of the lifting hook and the bundling of strands with a sleeve should
be taken into account by the factors k and k :
1 2
N = k ⋅ k ⋅ A ⋅ f
Rk,s 1 2 s uk
The reduction factors k and k to consider the influence of the diameter of the lifting hook and bundled strands are
1 2
given in Table 8 and 9.
In the case when a steel sleeve is used for a single strand loop, factor k may be increased by 25%, however
k ≤ 1,0.
Table 8 — Influence of the lifting hook, capacity reduction factors for lifting loops made of strands
Diameter 2s [mm] k
0,65
25 or γ ≤ 60
50 0,8
≥ 75 0,9
Table 9 — Reduction factors for lifting loops made of bundled strands
Number of strands 2 3 4
k
2 0,90 0,85 0,75
8.3.2 Minimum thickness of wall or element
The thickness of the wall shall be sufficient to avoid failure modes that cannot be counteracted effectively by
reinforcement.
Type a) inserts
For type a) inserts a side-face blow-out failure may occur at the built-in end of the insert, see Figure 15.

Figure 15 — Side face blow-out failure
The risk of a blow-out failure depends primarily on the anchor force, the concrete strength and the edge distance.
The strength may be found from the following expression, [1]:
π
2 2
N = 11,4⋅c⋅ (d − d )⋅ f [N]
Rk h ck
For inserts with a head diameter, d [mm], larger than 2,4 times the shaft diameter, d [mm], (d ≥ 2,4d) this may on
h h
the safe side be replaced by
k
N = k ⋅ψ ⋅ h ⋅ f
Rk 3 c ck
ef
[N]
where c [mm] is the edge distance, f [N/mm ] is the concrete strength and
ck
The curves given in Figure 16 are based on this latter expression assuming that the insert is placed in the middle of
the wall. If not, the wall thickness should be assumed to be twice the smallest edge distance. The diagram also
assumes that partial safety factors for steel and concrete are the same. If the partial safety factor to be used is
smaller for steel than for concrete
...