SIST-TP CEN/TR 15728:2016
(Main)Design and use of inserts for lifting and handling of precast concrete elements
Design and use of inserts for lifting and handling of precast concrete elements
1.1 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). The range of these applications is further limited to prevent other types of failure than concrete breakout failure (cone failure), bond failure, failure of reinforcement or failure in the steel insert.
Due to lack of information this report does not cover double shell walls, floor plates and beams for beam-and-block floor systems.
The safety levels are given for information and 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 13369:2013, 6.3) covering the insert embedment.
This Technical Report does not cover:
- the design of the lifting inserts independently placed on the market;
- lifting inserts for permanent and repeated use.
This Technical Report is prepared based on the fact that the anchorage in the concrete of parts of the lifting assembly is governed by the Construction Products Regulation. Lifting accessories independently placed on the market are governed by the Machinery Directive.
1.2 Types of inserts for lifting and handling
This Technical Report applies to the embedment of lifting inserts. Devices made by the precaster may consist of smooth bars, prestressing strands, steel plates with anchorage or 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.
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 hef = 40 mm.
Wire ropes of diameter less than 6 mm are not covered.
Bemessung und Anwendung von Transportankern für Betonfertigteile - Elemente
Dieser Technische Bericht liefert Empfehlungen für die Wahl und Verwendung von Einlegeteilen aus Stahl für das Versetzen von Betonfertigteilen, die einbetoniert wurden und im Folgenden „Transportanker“ genannt werden. Transportanker sind nicht für die Nutzungsdauer des Tragwerks vorgesehen, sondern lediglich für die Verwendung in vorübergehenden Situationen während des Hebens und Versetzens. Die Wahl des Transportankers erfolgt entsprechend der Tragfähigkeit des in den Beton eingebetteten Teils oder kann durch die vom Hersteller angegebene Tragfähigkeit des Transportankers selbst und des entsprechenden Lastaufnahmemittels begrenzt sein.
Der Bericht behandelt häufige Anwendungen (Wände/Balken/Stützen und Massivplatten sowie Rohre). Dieser Anwendungsbereich ist weiterhin begrenzt, um andere Versagensarten als den Betonausbruch (kegelförmiges Versagen), das Verbundversagen, das Versagen von Bewehrung oder das Versagen des Transportankers auszuschließen.
Aufgrund fehlender Informationen behandelt dieser Bericht keine doppelschaligen Wände, Deckenplatten mit Ortbetonergänzung und Balken für Balkendecken mit Zwischenbauteilen.
Die Sicherheitsniveaus sind zu Informationszwecken angegeben und gelten für die kurzfristige Handhabung und für vorübergehende Situationen.
Dieser Technische Bericht gilt nur für Betonfertigteile, die aus Normalbeton bestehen und in einem Werk unter einem System der werkseigenen Produktionskontrolle (WPK) (in Übereinstimmung mit EN 13369:2013, 6.3), das die Verankerung von Transportankern beinhaltet, hergestellt wurden.
Dieser Technische Bericht umfasst nicht:
die Konstruktion von Transportankern, die unabhängig in Verkehr gebracht werden;
Transportanker zur ständigen und wiederholten Nutzung.
Dieser Technische Bericht wurde basierend auf der Tatsache erarbeitet, dass die Verankerung von Teilen von Transportankersystemen im Beton durch die Bauproduktenverordnung geregelt ist. Hilfsmittel zum Versetzen von Betonfertigteilen, die unabhängig in Verkehr gebracht werden, sind durch die Maschinenrichtlinie geregelt.
1.2 Arten von Transportankern für das Heben und Versetzen
Dieser Technische Bericht beinhaltet die Verankerung von Transportankern. Transportvorrichtungen, die durch einen Fertigteilhersteller gefertigt werden, können aus glattem Bewehrungsstahl, Spannstahllitzen, Stahlplatten mit Verankerung oder Stahldrahtseilen bestehen. Bestandteile eines Transportankersystems können z. B. Transportanker mit Innengewinde, aus Flachstahl oder mit Kopfbolzen sein.
Schlaufenförmige Transportanker aus Betonrippenstahl werden nicht behandelt
Conception et utilisation d'inserts pour le levage et la manutention du béton préfabriqué - Éléments
Dimenzioniranje in uporaba transportnih sider za betonske polizdelke - Elementi
1.1 Splošno
To tehnično poročilo podaja priporočila za izbiro in uporabo litih jeklenih dvižnih sider (v nadaljevanju »sidra«) za transport montažnih betonskih elementov. Ta sidra so namenjena za dvigovanje in transport v prehodnih obdobjih, ne pa za dobo trajanja konstrukcije. Izbira sidra je odvisna od nosilnosti njegovega dela, vdelanega v beton, ali je omejena glede na nosilnost samega sidra in specifikacije proizvajalca.
Poročilo zajema običajne načine uporabe (zidovi/tramovi/stebri ter trdne plošče in cevi). Obseg teh načinov uporabe je dodatno omejen, da se preprečijo druge vrste napak, ki ne vključujejo napak zaradi razpokanega betona (konusa), sprijemne trdnosti, armature ali jeklenega sidra.
To poročilo zaradi pomanjkanja informacij ne zajema zidov z dvojno zaščito, talnih plošč in manjših tramov za talne sisteme.
Stopnje varnosti so informativne in namenjene za kratkotrajen transport in prehodna obdobja.
To tehnično poročilo se uporablja samo za montažne betonske elemente, ki so izdelani iz betona običajne teže v tovarni s sistemom kontrole proizvodnje (v skladu s standardom EN 13369:2013, 6.3) in ki pokrivajo območje sidra.
To tehnično poročilo ne zajema:
– oblik dvižnih sider, ki so na tržišču na voljo posebej;
– dvižnih sider za trajno in večkratno uporabo.
To tehnično poročilo je pripravljeno na podlagi tega, da je sidrišče v betonskem delu dvižnega sklopa opredeljeno v Uredbi o gradbenih proizvodih. Dvižni pripomočki, ki so na tržišču na voljo posebej, so opredeljeni v Direktivi o strojih.
1.2 Vrste sider za dvigovanje in transport
To tehnično poročilo se uporablja za območje dvižnih sider. Naprave, ki jih izdela stroj za proizvodnjo montažnih proizvodov, lahko vključujejo gladke armaturne palice, pramena za prednapetje, jeklene plošče s sidriščem ali jeklene žične vrvi. Sistemske naprave so lahko npr. notranja navojna sidra, ploska jeklena sidra in glavnata sidra.
Dvižne zanke iz rebrastih palic niso zajete v tem poročilu.
1.3 Najmanjše dimenzije
To tehnično poročilo se na splošno uporablja za sidra z najmanjšim nominalnim premerom 6 mm ali z ustreznim presekom. Na splošno mora biti najmanjša globina sidrišča hef = 40 mm.
Žične vrvi s premerom manj kot 6 mm niso zajete v tem poročilu.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2016
1DGRPHãþD
SIST-TP CEN/TR 15728:2008
Dimenzioniranje in uporaba transportnih sider za betonske polizdelke - Elementi
Design and use of inserts for lifting and handling of precast concrete elements
Bemessung und Anwendung von Transportankern für Betonfertigteile - Elemente
Conception et utilisation d'inserts pour le levage et la manutention du béton préfabriqué -
Éléments
Ta slovenski standard je istoveten z: CEN/TR 15728:2016
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.
CEN/TR 15728
TECHNICAL REPORT
RAPPORT TECHNIQUE
February 2016
TECHNISCHER BERICHT
ICS 91.100.30 Supersedes CEN/TR 15728:2008
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 Anwendung von Transportankern für
manutention du béton préfabriqué - Éléments Betonfertigteile - Elemente
This Technical Report was approved by CEN on 27 July 2015. It has been drawn up by the Technical Committee CEN/TC 229.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15728:2016 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
1 Scope . 5
1.1 General . 5
1.2 Types of inserts for lifting and handling . 5
1.3 Minimum dimensions . 5
2 Normative references . 5
3 Terms and definitions and symbols . 6
3.1 Definitions . 6
3.2 Symbols . 8
3.2.1 Action and resistance . 8
3.2.2 Concrete and steel . 8
3.2.3 Inserts. 9
4 Basis of design . 9
4.1 General . 9
4.2 Required verifications . 9
4.3 Design Principles . 9
4.3.1 Limit state design . 9
4.3.2 Ultimate limit state . 9
4.3.3 Admissible load design . 10
4.4 Verification . 11
4.4.1 General . 11
4.4.2 Partial factor method (Ultimate limit state) . 11
5 Actions on inserts . 12
5.1 General . 12
5.2 Effect of lifting procedures on load directions . 13
5.3 Actions from adhesion and form friction . 14
5.4 Dynamic actions. 15
5.5 Combined actions . 16
6 Design of lifting inserts and anchorage in concrete by calculation . 16
6.1 General conditions . 16
6.2 Types of inserts covered . 17
6.2.1 Inserts independently placed on the market . 17
6.2.2 Inserts made by the precaster . 19
6.3 General design . 19
6.3.1 Failure modes . 19
6.3.2 Design procedures . 20
6.3.3 Unreinforced concrete . 20
6.3.4 Reinforced concrete . 22
6.4 Lifting inserts . 24
6.4.1 General design . 24
6.4.2 Lifting loops of smooth bars . 24
6.4.3 Lifting loops of strands . 26
6.4.4 Lifting loops of steel wire ropes . 26
6.5 Lifting of walls and linear elements . 27
6.5.1 General . 27
6.5.2 Minimum thickness of wall or element . 28
6.5.3 Anchorage reinforcement . 28
6.6 Lifting of slabs and pipes . 30
6.6.1 Minimum edge distances . 30
6.6.2 Anchorage reinforcement . 30
7 Design of lifting inserts and anchorage in concrete by testing . 31
7.1 General conditions . 31
7.2 Specification of specimens . 32
7.2.1 Areas of application . 32
7.2.2 Design of test specimen . 32
7.2.3 Age of concrete specimen at testing . 34
7.2.4 Specification of inserts. 34
7.3 Loading conditions . 34
7.3.1 Load and support conditions . 34
7.3.2 Loading history . 35
7.3.3 Measurements . 35
7.4 Test programs . 35
7.4.1 General . 35
7.4.2 Tests to verify prior knowledge . 36
7.4.3 Tests utilizing no prior knowledge — Determination of properties for one insert
used for specific applications . 36
7.5 Assessment of the test results . 36
7.6 Test report . 36
7.6.1 General information . 36
7.6.2 Test members . 37
7.6.3 Installation of the insert . 37
7.6.4 Measured values . 37
7.6.5 Evaluation report . 38
8 Lifting and handling instructions . 38
Annex A (informative) Information to be given by the insert supplier . 39
A.1 Information on the content of an operational manual . 39
Annex B (informative) Use of Supplier’s recommendations . 42
Bibliography . 43
European foreword
This document (CEN/TR 15728:2016) has been prepared by Technical Committee CEN/TC 229
“Precast concrete products”, the secretariat of which is held by AFNOR.
This document supersedes CEN/TR 15728:2008.
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 lifting inserts cast into precast concrete elements. 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 according to the lifting and handling instructions.
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), EN 1993-1-1 (Eurocode 3), CEN/TS 1992-4-1 and on published supplier’s
data.
Safety levels should be determined nationally. In the Technical Report numerical values for safety
factors as used in different CEN member states are given for information and 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.
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.
1 Scope
1.1 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). The range of these applications is further limited to prevent other types of failure than
concrete breakout failure (cone failure), bond failure, failure of reinforcement or failure in the
steel insert.
Due to lack of information this report does not cover double shell walls, floor plates and beams for
beam-and-block floor systems.
The safety levels are given for information and 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 13369:2013, 6.3) covering the insert embedment.
This Technical Report does not cover:
— the design of the lifting inserts independently placed on the market;
— lifting inserts for permanent and repeated use.
This Technical Report is prepared based on the fact that the anchorage in the concrete of parts of the
lifting assembly is governed by the Construction Products Regulation. Lifting accessories independently
placed on the market are governed by the Machinery Directive.
1.2 Types of inserts for lifting and handling
This Technical Report applies to the embedment of lifting inserts. Devices made by the precaster may
consist of smooth bars, prestressing strands, steel plates with anchorage or 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.
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 h = 40 mm.
ef
Wire ropes of diameter less than 6 mm are not covered.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 1993-1-1:2005, Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings
EN 10025-2, Hot rolled products of structural steels - Part 2: Technical delivery conditions for non-alloy
structural steels
EN 12385-4, Steel wire ropes — Safety — Part 4: Stranded ropes for general lifting applications
EN 13369:2013, Common rules for precast concrete products
EN 13414-1, Steel wire rope slings — Safety — Part 1: Slings for general lifting service
3 Terms and definitions and symbols
For the purposes of this document, the following terms and 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
resistance corresponding to a concrete cone surrounding the insert or group of inserts separating from
the member
3.1.3
edge distance
distance from the edge of the concrete surface to the centre of the nearest insert
3.1.4
anchorage length
for cast-in headed insert bolts and splayed inserts is illustrated in Figure 1
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
quality system satisfying the requirements in EN 13369:2013, 6.3
3.1.7
headed insert
steel insert with a head for anchorage installed before placing concrete
3.1.8
insert
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 system
system of lifting key and appropriate insert
3.1.12
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 Machinery Directive 2006/42/EC)
3.1.13
precaster
producer of precast concrete elements in a factory environment
3.1.14
pullout failure
failure mode in which the insert pulls out of the concrete without a steel failure and without a concrete
breakout failure
3.1.15
side-face blow-out resistance
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
3.1.16
insert steel failure
failure mode characterised by fracture of one of the steel insert parts
3.1.17
minimum reinforcement
reinforcement required by EN 1992-1-1 or in national annex (Nationally Determined Parameter)
3.1.18
anchorage reinforcement
reinforcement designed to resist the full load in case of a concrete failure
3.1.19
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 loads;
load
γ partial factor for lifting and handling effects;
l+h
γ partial factor for concrete;
c
γ partial factor for steel.
s
3.2.2 Concrete and steel
A stressed cross section of steel;
s
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 ultimate strength of steel;
tk
f characteristic strength at the 0,1 limit for prestressing steel;
0,1k
F specified characteristic value of 0,1 % proof force, defined by prEN 10138–3:2000;
p0,1
F F is the minimum breaking force of the rope, in kilonewtons, defined by EN 13414–1;
min min
f and f design values of stress;
yd cd
F design value of force in prestressing strand;
pd
f design value of stress in prestressing strand;
pd
F design value of force in wire ropes.
yd
3.2.3 Inserts
Notation and symbols frequently used in this technical report are given below. Other notation and
symbols are given in the text.
a edge distance from the axis of an insert.
∅ diameter of insert bolt or thread
diameter.
∅ diameter of insert head (headed
h
inserts).
∅ diameter of reinforcing bar.
s
h anchorage length (Figure 1).
ef
4 Basis of design
4.1 General
Inserts for lifting and handling should sustain all actions and influences likely to occur during execution
and use, thus preventing any structural failure (ultimate limit state). They should not deform to an
inadmissible degree (serviceability limit state). Long term effects such as corrosion of the insert should
be taken into account by the designer.
In the design of lifting inserts it is assumed that they are produced with ductile materials having
pronounced deformations before failure. The deformability should be maintained with age and under
low temperatures.
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.
4.2 Required verifications
Ultimate limit state (ULS) and serviceability limit state design (SLS) are commonly used in present
structural design. This design concept is based on partial factors.
For transient lifting and handling situations the admissible load design concept based on global factors
was established in the past and is still and very often used in daily lifting insert design practice.
Both methods of verification of lifting inserts are described in the following.
4.3 Design Principles
4.3.1 Limit state design
For the inserts the following should be verified:
4.3.2 Ultimate limit state
4.3.2.1 General
In the ultimate limit state verifications are required for all appropriate load directions.
It should be shown that:
E ≤ R (4.1)
d d
where
E = design value of effect of actions with E = E × γ ;
d d load
E = effect of actions loading the insert;
γ = partial factor for load;
load
R = design value of resistance of the insert, with R = R / γ ;
d d k M
R = characteristic value of resistance;
k
γ = partial factor for material.
M
4.3.2.2 Servicability limit state
In service limit state the inserts should not significantly deform and the material of the insert and the
corrosion protection should be selected taking into account the environmental conditions of the final
structure if the insert remains in the precast element over service life in the structure.
It should be shown that:
EC≤ (4.2)
dd
where
E = design value of insert deformation;
d
C = nominal value, e.g. limiting
d
deformation.
Actions should be obtained from the relevant parts of EN 1991-1 where applicable.
4.3.3 Admissible load design
The design of lifting inserts may be carried out on the basis of allowable loads, since the manuals of the
lifting insert suppliers normally only provides admissible loads for their inserts. This concept is based
on global safety factors and requires that the action E does not exceed the admissible resistance R .
adm
It should be shown that:
E ≤ R (4.3)
adm
where
E = effect of actions loading the insert;
R = admissible load on the insert provided by the
adm
supplier.
The admissible resistance of lifting inserts according to this technical report is:
Radm = Rk / γ (4.4)
where
R = characteristic value of resistance;
k
γ = global safety factor, factor to cover uncertainties in action and resistance.
4.4 Verification
4.4.1 General
The verification of the resistance should be for all actions and load directions. The method used for
verification may be ultimate limit state and service limit state (partial factors), or admissible load
design (global safety factors).
4.4.2 Partial factor method (Ultimate limit state)
4.4.2.1 Partial factors for actions
Partial factors for actions to be used are given in EN 1990:2002, Annex A.
In the absence of National provisions the for partial factor γ , globally taking into account model
load
uncertainties for dead load and live load, i.e. self-weight, adhesion, form friction and dynamic actions
the following value is recommended:
γ = 1,35
load
4.4.2.2 Partial factors for resistance
In the absence of National provisions the partial factors given for steel failure in Table 1 and for
concrete and anchorage failure in Table 2 are recommended.
Table 1 — Partial safety factors γ for steel failure
s
Insert γ γ Reference standards Minimum Design values
s l+h
material a ductility ratio, k
for steel strength f , f F
yd pd, yd
= ftk/fyk
Structural 1,2 1,8 EN 10025–2 1,10 f = f / (γ × γ ) = f / 2,25
yd yk s l+h yk
solid steel 5
Reinforcing National Standards or
steel information by the
1,1
1,8 1,15 f = f / (γ × γ ) = f / 2,07
yd yk s l+h yk
producers.
(smooth
bars)
Prestressing 1,1 1,8 prEN 10138–3:2000, 1,10 F = F / (γ × γ ) = F /
pd 0,1k s l+h 0,1k
strand 5 National Standards or 2,07
information by the
or
producers.
f = f / (γ × γ ) = f / 2,07
pd 0,1k s l+h 0,1k
Wire rope 1,1 1,8 EN 12385–4 or 1,54 Fyd = Fmin / (γs × γl+h) = Fmin /
5 EN 13414–1 2,07
a
See also 6.4.
Recommended values of the partial factor for failures in the load transfer between the insert and the
concrete 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 2 — Partial safety factors for concrete and anchorage failure
Precast element γ , γ γ Design values
c s l+h
Concrete 1,5 1,5 fcd = fc /(γc × γl+h) = fc / 2,25
Anchorage of reinforcement 1,15 1,5 fyd = fy /(γs × γl+h) = fy / 1,75
4.4.2.3 Global safety factor method
Values for the global safety factor γ from different Nations for the different verifications are given in
Table 3. For comparison the global factors are compared with the partial factors for the partial factor
method of 4.4.2.2 using the following approach:
γ = γ × (γ × γ ) for steel failure (4.5a)
load s l+h
γ = γ × (γ × γ ) for concrete or anchorage failure (4.5b)
load c l+h
Table 3 — Global safety factors γ used in different National provisions and MD 2006/42/EC
Verification of
b f b c
Structural steel
3,0 3 3,04 4
b b b
Reinforcing steel (smooth bars)
2,8 2,35 2,80
b b
Prestressing strands
2,8 2,80
b b
2,8 2,80
f c c
Wire ropes
4 4 5
c e c e
4,3 4,30
2,5 or
Concrete failure 3,0 3,04 4
d
2,1
b b c
Anchorage reinforcement
2,3 2,33 4
a
The Machinery Directive 2006/42/EC includes a dynamic factor. VDI/BV-BS 6205 assumes this factor to be
1,3.
b
Verification for f , f or f (yield strength), F (force at 0,1 limit).
yk 0,1k 0,2k p0,1
c
Verification by calculation for ftk (tensile strength), Fmin (tensile force).
d
γ = 2,1 might be applied if lifting inserts are installed in precast elements under plant specific and continuous
inspection.
e
2,8 × k = 2,8 × 1,54 = 4,3.
f
Verification by calculation for ftk (tensile strength), or verification by testing for Rk (characteristic value of the
insert).
5 Actions on inserts
5.1 General
Generally actions should be taken from EN 1991-1.
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.
Concrete Inserts
4.3.3
Fascicule 65 (France)
a
VDI/BV-BS 6205
(Germany)
Conc. Elem. Book, C5
2013 edition (Norway)
PCI (for information: USA)
Machinery Directive
a
2006/42/EC
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
and Figure 4). 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
hh+ hh ×cosβ
12 11
tanα= tanδ
b bb/ cosβ
2 11
hh/ tanα
PP/4
tanβ F
bb × tanα sinδδ4×sin
PP/2
F
hb×
sinαα2×sin
1 2
tanβ=
b ×()hh+
1 12
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)
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 3/4 of the nominal diameter of the insert.
5.3 Actions from adhesion and form friction
Adhesion and form friction will act on the precast element when it is removed from the form. 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 4 may be considered.
adh
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
close to 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 – or nearly 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 4 — Examples of values for adhesion and form friction, q
adh
a
Formwork and condition
qadh
Asymetrically prestressed elements 0 to 0,6 kN/m
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
a
The area to be used in the calculations is the total contact area between the concrete and
the form.
The values given here may be minimum values. Individual consideration should be carried out.
The values of Table 4 are valid only if suitable measures to reduce adhesion and form friction are taken
e.g. casting on tilting tables or vibrating the formwork during the demoulding process.
The actions E for demoulding situations in ULS should be determined from:
d
E =(Gq+ × A )×γ (5.1a)
d,adh adh f load
or in case of admissible load design:
E =(Gq+× A ) (5.1b)
adh adh f
where
G = weight of the precast concrete element;
A = form area in contact with concrete;
f
γ = partial factor for loads (self-weight, adhesion, form friction and dynamic actions).
load
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 ψdyn given in National regulations. In the
absence of National Regulations the values of Table 5 may be considered. Other dynamic influences
than covered by Table 5 should be based on special provisions or engineering judgement.
Table 5 — Influence of dynamic actions on site
Dynamic influences Dynamic coefficient (ψdyn)
a
Tower crane, overhead crane and portal crane 1,2
a
Mobile crane 1,4
Lifting and moving on flat terrain 2 – 2,5
Lifting and moving on rough terrain 3 – 4
a
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 Formula (4).7a):
d
EGψγ×× (5.2a)
d,dyn dyn load
or in case of admissible load design:
EGψ× (5.2b)
dyn dyn
The actions E or E to be used in the design of the lifting insert and it’s anchorage should be the largest
d
of E or E in ULS, and E or E in admissible load design.
d,adh d,dyn adh dyn
5.5 Combined actions
Combined actions on lifting devices will in most cases be tension and shear.
1,5 1,5
If concrete is the governing parameter: (N / N ) + (V / V ) ≤ 1,0.
Ed Rd,c Ed Rd,c
2 2
If steel is the governing parameter: (N / N ) + (V / V ) ≤ 1,0
Ed Rd,s Ed Rd,s
5/3 5/3
If concrete is governing for one type of failure and steel for the other: (N / N ) + (V / V ) ≤ 1,0
Ed Rd Ed Rd
Here N and V are the smallest capacities of steel, welds or concrete.
Rd Rd
6 Design of lifting inserts and anchorage in concrete by calculation
6.1 General conditions
For most common applications, present practice and available general information, the load capacity of
inserts can be expressed in a design model. This model is described in 6.3. The model is not universally
applicable. Limitations on the range of validity are used to exclude situations where failures other than
concrete break out failure, bond failure, failure of anchorage reinforcement or steel failure of the insert.
Limitations on the range of validity are the following:
1) Fields of application
The most common fields of application are:
1) 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) see 6.4;
2) 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 – see 6.5.
2) Anchorage reinforcement is provided in the region of the insert if the concrete capacity is
not sufficient.
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 the concrete
around the insert. If minimum reinforcement is not provided complementary reinforcement
should be provided
Anchorage 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 reinforcement are in
accordance with the rules given in EN 1992-1-1.
=
=
3) Minimum characteristic strength of concrete.
It is recommended 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 13369:2013, 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) Handling procedures.
Lifting design should correspond to the actual handling situations. Handling procedures as
described in EN 13670:2009, 9.4, should include allowable lifting angles and handling
situations. The precaster should provide an information system for these requirements. See
Clause 8.
6.2 Types of inserts covered
6.2.1 Inserts independently placed on the market
All inserts shown in Figures 6 to 11 are commercially available.
All these standard lifting systems consist of an insert embedded in the concrete element and a matching
unit (key) that connects to the insert (Figures 6 to 11). The crane hook or hook of a lifting sling attaches
to the key. The combination of components from different systems is prohibited.
In many cases different types of cast-in-inserts belong to the same system. This can be confirmed by
checking the marking of the lifting system.
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 6 — Headed bolts and spread anchors
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 7 — Anchors with additional rebar
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 8 — Anchor systems with threaded sockets
These inserts may have 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 9 — Short versions of headed bolts and spread anchors
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 10 — Short versions of headed bolts and spread anchors
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.
Figure 11 — Plate sockets
6.2.2 Inserts made by the precaster
In addition to the commercially available inserts the precasters may produce their own lifting devices
as welded units, or made from smooth bars, prestressing strands or steel wire ropes. Necessary
information on the handling of the element considered in the design, e.g. lifting hook dimensions,
should be given in handling specifications.
Lifting loops should only be used if the lifting angle is approximately the same in all lifting
...
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