SIST EN 1168:2005
(Main)Precast concrete products - Hollow core slabs
Precast concrete products - Hollow core slabs
This European Standard deals with the requirements and the basic performance criteria and specifies minimum values where appropriate for precast hollow core slabs made of prestressed or reinforced normal weight concrete according to EN 1992-1-1:2004.
This European Standard covers terminology, performance criteria, tolerances, relevant physical properties, special test methods, and special aspects of transport and erection.
Hollow core elements are used in floors, roofs, walls and similar applications. In this European Standard the material properties and other requirements for floors and roofs are dealt with; for special use in walls and other applications, see the relevant product standards for possible additional requirements.
The elements have lateral edges provided with a longitudinal profile in order to make a shear key for transfer of vertical shear through joints between contiguous elements. For diaphragm action the joints have to function as horizontal shear joints.
The elements are manufactured in factories by extrusion, slipforming or mouldcasting.
The application of the standard is limited for prestressed elements to a maximum depth of 450 mm and a maximum width of 1 200 mm. For reinforced elements the maximum depth is limited to 300 mm and the maximum width without transverse reinforcement to 1 200 mm and with transverse reinforcement to 2 400 mm.
The elements may be used in composite action with an in situ structural topping cast on site.
The applications considered are floors and roofs of buildings, including areas for vehicles in the category F and G of EN 1991-2 which are not subjected to fatigue loading. For building in seismic zones additional provisions are given in EN 1998-1.
This European Standard does not deal with complementary matters. E.g. the slabs should not be used in roofs without additional protection against water penetration.
Betonfertigteile - Hohlplatten
Diese Europäische Norm legt die Anforderungen und die grundlegenden Leistungskriterien und, sofern dies angemessen ist, in Übereinstimmung mit EN 1992-1-1 die Mindestwerte für vorgefertigte Spannbeton- oder Stahlbetonhohlplatten fest.
Diese Norm behandelt die Terminologie, Leistungskriterien, Toleranzen, wesentliche physikalische Eigen-schaften, besondere Prüfverfahren und speziell auf den Transport und die Montage bezogene Aspekte.
Hohlplatten werden für Decken, Dächer, Wände und ähnliche Anwendungsbereiche verwendet. In dieser Norm werden die Baustoffeigenschaften und andere Anforderungen an Decken und Dächer behandelt; für den Sonderfall der Verwendung für Wände und sonstige Anwendungen wird auf die entsprechenden Produktnormen hinsichtlich möglicher zusätzlicher Anforderungen verwiesen.
Die Bauteile haben Seitenkanten mit einer Längsprofilierung zur Bildung eines Querkraftschlusses zur Über-tragung von vertikalen Querkräften über die Fugen zwischen zwei benachbarten Bauteilen. Um die Scheiben-wirkung sicherzustellen, müssen die Fugen als horizontale Schubfugen wirken.
Die Bauteile werden in Fertigteilwerken mit Extrudern, Gleitfertigern oder in Einzelformen hergestellt.
Die Anwendung der Norm ist beschränkt auf Spannbetonbauteile mit einer maximalen Dicke von 450 mm und einer maximalen Breite von 1 200 mm. Bei Stahlbetonbauteilen ist die maximale Dicke auf 300 mm und die maximale Breite ohne Querbewehrung auf 1 200 mm und mit Querbewehrung auf 2 400 mm beschränkt.
Die Bauteile dürfen als Verbundbauteil mit einer statisch mitwirkenden Ortbetonschicht verwendet werden.
Der Anwendungsbereich umfasst Decken und Dächer von Gebäuden, einschließlich Fahr- und Parkflächen für Fahrzeuge der Kategorien F und G nach EN 1991-2, die keinen Ermüdungseinwirkungen unterworfen sind. Für das Bauen in Erdbebengebieten sind in EN 1998-1 zusätzliche Vorschriften angegeben.
Diese Norm gilt nicht für ergänzende Dinge. So sollten die Platten z. B. nicht ohne zusätzlichen Schutz
Produits préfabriqués en béton - Dalles alvéolées
La présente Norme européenne spécifie les prescriptions et les criteres relatifs aux performances de base, et
spécifie, lorsque nécessaire, les valeurs minimales pour les dalles alvéolées préfabriquées en béton de
masse volumique normale précontraint ou armé, conformément a l'EN 1992-1-1:2004.
La présente Norme européenne couvre la terminologie, les criteres de performances, les tolérances, les
propriétés physiques pertinentes, les méthodes d'essai particulieres et les aspects relatifs au transport et a la
mise en oeuvre.
Les dalles alvéolées sont utilisées dans les planchers, les toitures, les murs et pour des applications similaires.
Dans la présente norme, sont traitées les propriétés des matériaux ainsi que d'autres prescriptions pour une
utilisation en planchers et en toitures ; pour des utilisations spéciales en murs et autres applications, se
reporter aux éventuelles prescriptions supplémentaires dans les normes de produits concernées.
Les bords latéraux des éléments présentent un profil longitudinal afin de former une clé de cisaillement pour
le transfert du cisaillement vertical a travers les joints entre éléments contigus. Pour la fonction diaphragme,
les joints doivent permettre la transmission du cisaillement horizontal.
Les éléments sont fabriqués en usine par extrusion, filage ou moulage.
L'application de la présente norme est limitée aux éléments précontraints ayant une hauteur maximale de
450 mm et une largeur maximale de 1 200 mm. Pour les éléments armés, la hauteur maximale est limitée a
300 mm, la largeur maximale a 1 200 mm pour les éléments sans armatures transversales et a 2 400 mm
pour les éléments avec armatures transversales.
Montažni betonski izdelki – Votle plošče
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 1168:2005
01-julij-2005
0RQWDåQLEHWRQVNLL]GHONL±9RWOHSORãþH
Precast concrete products - Hollow core slabs
Betonfertigteile - Hohlplatten
Produits préfabriqués en béton - Dalles alvéolées
Ta slovenski standard je istoveten z: EN 1168:2005
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
SIST EN 1168:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 1168:2005
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SIST EN 1168:2005
EUROPEAN STANDARD
EN 1168
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2005
ICS 91.060.30; 91.100.30
English version
Precast concrete products - Hollow core slabs
Produits préfabriqués en béton - Dalles alvéolées Vorgefertigte Betonerzeugnisse - Hohlplatten
This European Standard was approved by CEN on 1 July 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1168:2005: E
worldwide for CEN national Members.
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SIST EN 1168:2005
EN 1168:2005 (E)
Contents
The numbering of clauses is strictly related to EN 13369: Common rules for precast concrete products, at least for
the first three digits. When a clause of EN 13369 is not relevant or included in a more general reference of this
standard, its number is omitted and this may result in a gap on numbering.
Foreword .3
Introduction.5
1 Scope .6
2 Normative references .6
3 Terms and definitions.7
4 Requirements .8
5 Test methods.18
6 Evaluation of conformity .19
7 Marking .19
8 Technical documentation.19
Annex A (normative) Inspection schemes.20
Annex B (informative) Typical shapes of joints .22
Annex C (informative) Transverse load distribution.24
Annex D (informative) Diaphragm action.32
Annex E (informative) Unintended restraining effects and negative moments .33
Annex F (informative) Mechanical resistance in case of verification by calculation: shear capacity of
composite members .36
Annex G (informative) Resistance to fire.39
Annex H (informative) Design of connections.42
Annex J (normative) Full scale test.44
Annex Y (informative) Choice of CE marking method .47
Annex ZA (informative) Clauses of this European Standard addressing essential requirements or
other provisions of EU Directives.48
Bibliography.59
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SIST EN 1168:2005
EN 1168:2005 (E)
Foreword
This document (EN 1168:2005) has been prepared by Technical Committee CEN/TC 229 “Precast concrete
products”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by November 2005, and conflicting national standards shall be withdrawn at the latest
by May 2007.
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.
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports essential requirements of Construction Products Directives (89/106/EEC) of
the European Union (EU).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document.
This standard is one of a series of product standards for precast concrete products.
For common aspects reference is made to EN 13369 : Common rules for precast products, from which also the
relevant requirements of the EN 206-1 : Concrete - Part 1 : Specification, performances, production and conformity
are taken.
The references to EN 13369 by CEN/TC 229 product standards are intended to make them homogeneous and to
avoid repetitions of similar requirements.
Eurocodes are taken as a common reference for design aspects. The installation of some structural precast
concrete products is dealt with by ENV 13670-1 : Execution of concrete structures – Part1 : Common rules, which
has at the moment the status of an European Prestandard. In all countries it can be accompanied by alternatives
for national application and it shall not be treated as a European standard.
The programme of standards for structural precast concrete products comprises the following standards, in some
cases consisting of several parts :
EN 1168, Precast concrete products – Hollow core slabs
EN 12794, Precast concrete products – Foundation piles
EN 12843, Precast concrete products – Masts and poles
EN 13224, Precast concrete products – Ribbed floor elements
EN 13225, Precast concrete products – Linear structural elements
EN 13693, Precast concrete products – Special roof elements
prEN 13747, Precast concrete products – Floor plates for floor systems
prEN 13978, Precast concrete products – Precast concrete garages
prEN 14843, Precast concrete products - Stairs
prEN 14844, Precast concrete products – Box culverts
prEN 14991, Precast concrete products – Foundation elements
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SIST EN 1168:2005
EN 1168:2005 (E)
prEN 14992, Precast concrete products – Wall elements : Production properties and performances
prEN 15258, Precast concrete products – Retaining wall elements
prEN 15050, Precast concrete products – Bridge elements
This standard defines in Annex ZA the application methods of CE marking to products designed using the relevant
EN Eurocodes (EN 1992-1-1 and EN 1992-1-2). Where, in default of applicability conditions of EN Eurocodes to the
works of destination, design Provisions other than EN Eurocodes are used for mechanical strength and/or fire
resistance, the conditions to affix CE marking to the product are described in ZA.3.4.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
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SIST EN 1168:2005
EN 1168:2005 (E)
Introduction
The evaluation of conformity given in this standard refers to the completed precast elements which are supplied to
the market and covers all the production operations carried out in the factory.
For design rules reference is made to EN 1992-1-1. Additional complementary rules are provided where necessary.
The verification of the mechanical resistance of hollow core slabs is, at this stage of standardisation, only fully
accepted by calculation; in Annex J ( Normative) a test method is given for confirmation of design model for shear
resistance.
Special rules for structures with hollow core elements are presented in annexes about load distribution (Annex C),
diaphragm action (Annex D), negative moments (Annex E), shear capacity of composite members (Annex F) and
design of connections (Annex H).
Because of some specialities of the product, e.g. the absence of transverse reinforcement, some complementary
design rules to EN 1992-1-1 are necessary. Furthermore, research on hollow core slabs has resulted in special,
widely used, design rules which are not incorporated in the design rules of EN 1992-1-1. According to
subclause 1.2 of EN 1992-1-1:2004 the complementary rules, given in informative annexes in this standard, comply
with the relevant principles given in EN 1992-1-1.
Because of the fact that the experimental evidence is mainly based on elements with limited depth and width, this
standard is applicable to elements with these limited dimensions. This limitation is not intended to prohibit the
application of elements with larger sizes, but the experience is not yet wide enough to draw up standardised design
rules.
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SIST EN 1168:2005
EN 1168:2005 (E)
1 Scope
This European Standard deals with the requirements and the basic performance criteria and specifies minimum
values where appropriate for precast hollow core slabs made of prestressed or reinforced normal weight concrete
according to EN 1992-1-1:2004.
This European Standard covers terminology, performance criteria, tolerances, relevant physical properties, special
test methods, and special aspects of transport and erection.
Hollow core elements are used in floors, roofs, walls and similar applications. In this European Standard the
material properties and other requirements for floors and roofs are dealt with; for special use in walls and other
applications, see the relevant product standards for possible additional requirements.
The elements have lateral edges provided with a longitudinal profile in order to make a shear key for transfer of
vertical shear through joints between contiguous elements. For diaphragm action the joints have to function as
horizontal shear joints.
The elements are manufactured in factories by extrusion, slipforming or mouldcasting.
The application of the standard is limited for prestressed elements to a maximum depth of 450 mm and a maximum
width of 1 200 mm. For reinforced elements the maximum depth is limited to 300 mm and the maximum width
without transverse reinforcement to 1 200 mm and with transverse reinforcement to 2 400 mm.
The elements may be used in composite action with an in situ structural topping cast on site.
The applications considered are floors and roofs of buildings, including areas for vehicles in the category F and G
of EN 1991-2 which are not subjected to fatigue loading. For building in seismic zones additional provisions are
given in EN 1998-1.
This European Standard does not deal with complementary matters. E.g. the slabs should not be used in roofs
without additional protection against water penetration.
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 206-1:2000, Concrete – Part 1: Specification, performance, production and conformity.
EN 1992-1-1:2004, Eurocode 2: Design of concrete structures – Part 1-1: General rules and rules for buildings.
EN 1992-1-2:2004, Eurocode 2: Design of concrete structures – Part 1-2: General rules – Structural fire design.
EN 12390-2, Testing hardened concrete – Part 2: Making and curing specimens for strength tests.
EN 12390-3, Testing hardened concrete – Part 3: Compressive strength of test specimens.
EN 12390-4:2000, Testing hardened concrete – Part 4: Compressive strength – Specification for testing machines.
EN 12390-6, Testing hardened concrete – Part 6: Tensile splitting strength of test specimens.
EN 12504-1, Testing concrete in structures – Part 1: Cored specimens – Testing, examining and testing in
compression.
EN 13369:2004, Common rules for precast concrete products.
prEN 13791:2003, Assessment of concrete compressive strength in structures or in structural elements.
6
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SIST EN 1168:2005
EN 1168:2005 (E)
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply. For general terms
EN 13369:2004 shall apply.
3.1 Definitions
3.1.1
hollow core slab
monolithic prestressed or reinforced element with a constant overall depth divided into an upper and a lower flange,
linked by vertical webs, so constituting cores as longitudinal voids the cross section of which is constant and
presents one vertical symmetrical axis (see Figure 1)
Key
1 Core
2 Web
Figure 1 — Example of hollow core slab
3.1.2
core
longitudinal void produced by specific industrial manufacturing techniques, located with a regular pattern and the
shape of which is such that the vertical loading applied on the slab is transmitted to the webs
3.1.3
web
vertical concrete part between two adjacent cores (intermediate webs) or on the lateral edges of the slab
(outermost webs)
3.1.4
lateral joint
lateral profile on the longitudinal edges of a hollow core slab shaped so to allow grouting between two adjacent
slabs
3.1.5
topping
cast in situ concrete on the hollow core slab floor intended to increase its bearing capacity and so constituting a
composite hollow core slab floor
3.1.6
screed
cast in situ concrete or mortar layer used to level the upper face of the finished floor
3.1.7
hollow core slab floor
floor made of hollow core slabs after the grouting of the joints
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SIST EN 1168:2005
EN 1168:2005 (E)
3.1.8
composite hollow core slab floor
hollow core slab floor complemented by a cast-in-situ topping
4 Requirements
4.1 Material requirements
Complementary to 4.1 of EN 13369:2004 the following subclauses shall apply. In particular the ultimate tensile and
tensile yield strength of steel shall be considered.
4.1.1 Prestressing steel
4.1.1.1 Maximum diameter of prestressing steel
The diameter of prestressing steel is limited to a maximum of 11 mm for wires and 16 mm for strands. The use of
prestressing bars is not allowed.
4.2 Production requirements
Complementary to 4.2 of EN 13369:2004 the following subclauses shall apply. In particular the compressive
strength of concrete shall be considered.
4.2.1 Structural reinforcement
4.2.1.1 Processing of reinforcing steel
4.2.1.1.1 Longitudinal bars
For the distribution of the longitudinal bars the following requirements shall be fulfilled:
a) the bars shall be distributed uniformly across the width of the elements;
b) the maximum centre to centre distance between two bars shall not exceed 300 mm;
c) in the outermost webs there shall be at least one bar;
d) the clear spacing between bars shall be at least:
horizontally : ≥ (d + 5 mm), ≥ 20 mm and ≥ Ø;
g
vertically : ≥ d , ≥ 10 mm and ≥ Ø.
g
4.2.1.1.2 Transversal bars
Transverse reinforcement is not required in slabs up to 1 200 mm wide. Slabs having a width greater than
1 200 mm must have transverse reinforcement designed to suit the loading requirements. The minimum transverse
reinforcement shall be 5 mm diameter bars at 500 mm centres.
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SIST EN 1168:2005
EN 1168:2005 (E)
4.2.1.2 Tensioning and prestressing
4.2.1.2.1 Common requirements for the distribution of prestressing tendons
The following requirements shall be fulfilled:
a) the tendons shall be distributed uniformly across the width of the elements;
b) in every width of 1,20 m at least four tendons shall be applied;
c) in every element of a width greater than 0,60 m and less than 1,20 m, at least three tendons shall be applied;
d) in every element with a width of 0,60 m or less at least two tendons shall be applied;
e) the minimum clear spacing between tendons shall be:
horizontally : ≥ (d + 5 mm), ≥ 20 mm and ≥ Ø;
g
vertically : ≥ d , ≥ 10 mm and ≥ Ø.
g
4.2.1.2.2 Transfer of prestress
Clause 8.10.2.2 of EN 1992-1-1:2004 shall apply:
NOTE “Good” bond conditions are obtained for extruded and slip-formed elements. For the description of “good” and “poor”
bond conditions, see Figure 8.2 of EN 1992-1-1:2004.
4.3 Finished product requirements
4.3.1 Geometrical properties
4.3.1.1 Production tolerances
4.3.1.1.1 Dimensional tolerances related to structural safety
The maximum deviations, measured in accordance with 5.2, on the specified nominal dimensions shall satisfy the
following requirements:
a) slab depth:
h ≤ 150 mm: − 5 mm, + 10 mm;
h ≥ 250: ± 15 mm;
150 mm < h < 250 mm : linear interpolation may be applied;
b) nominal minimum web thickness:
individual web (b ): − 10 mm;
w
total per slab (Σb ): − 20 mm;
w
c) nominal minimum flange thickness (above and underneath cores):
individual flange: − 10 mm, + 15 mm;
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SIST EN 1168:2005
EN 1168:2005 (E)
d) vertical position of reinforcement at tensile side:
individual bar, strand or wire: h ≤ 200 mm ± 10 mm;
h ≥ 250 : ± 15 mm;
200 mm < h < 250 mm: linear interpolation may be applied;
mean value per slab: ± 7 mm;
the requirement in this paragraph shall not conflict with subclause 4.3.1.2.3 of this standard.
4.3.1.1.1 Tolerances for construction purposes
The maximum deviations, unless declared otherwise by the manufacturer, shall satisfy the following:
a) slab length: ± 25 mm;
b) slab width: ± 5 mm;
c) slab width for longitudinally sawn slabs : ± 25 mm.
4.3.1.1.2 Tolerances for concrete cover
4.3.1.2 Minimum dimensions
Complementary to 4.3.1.2 of EN 13369:2004 next subclauses shall apply.
4.3.1.2.1 Thickness of webs and flanges
The nominal thickness specified on the drawings shall be at least the minimum thickness increased by the
maximum deviation (minus tolerance) declared by the manufacturer.
The minimum thickness shall be:
for any web, not less than the largest of h/10, 20 mm and (d + 5 mm), where d and h are in millimetres;
g g
for any flange, not less than the largest value of 2h , 17 mm and (d + 5 mm), where d and h are in
g g
millimetres; however for the upper flange, not less than 0,25 b , where b is the width of that part of the flange
c c
in which the greatest thickness is not greater than 1,2 times the smallest thickness (see Figure 2).
Thickness of webs and flanges shall be measured in accordance with 5.2.1.1.
Figure 2 — Minimum thickness of upper flange
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SIST EN 1168:2005
EN 1168:2005 (E)
4.3.1.2.2 Minimum concrete cover and axis distances of prestressing steel
For indented wires or smooth and indented strands, the minimum concrete cover c to the nearest concrete
min
surface and to the nearest edge of a core shall be at least:
only with respect to the exposed face, the one determined in accordance with 4.4.1.2 of EN 1992-1-1:2004
shall apply;
for preventing longitudinal cracking due to bursting and splitting and in the absence of specific calculations
and/or tests:
when the nominal centre to centre distance of the strands ≥ 3 Ø : c = 1,5 Ø ;
min
when the nominal centre to centre distance of the strands < 2,5 Ø : c = 2,5 Ø ;
min
c may be derived by linear interpolation between the values calculated in a) and b);
min
where
Ø is the strand or wire diameter, in millimetres (in the case of different diameters in a strand, the average
value shall be used for Ø).
For ribbed wires, the concrete cover shall be increased with 1 Ø.
4.3.1.2.3 Minimum concrete cover of reinforcing steel
Clause 4.4.1.2 of EN 1992-1-1:2004 shall apply.
4.3.1.2.4 Longitudinal joint shape
The longitudinal joint width shall be:
at least 30 mm at the top of the joint;
greater than the larger value of 5 mm or d at the lower part of the joint, where d is the maximum aggregate
g g
size in the joint grout.
If tie bars, with a diameter of Ø, are to be placed and anchored in the longitudinal joint, the width of the joint at the
tie bar level shall be at least equal to the larger of (Ø + 20 mm) or (Ø + 2 d ), where d and Ø are in millimetres.
g g
When the longitudinal joint has to resist vertical shear, the joint face shall be provided with at least one groove.
The size of the groove shall be appropriate with regard to the resistance of the grout against vertical shear.
The height of the groove shall be at least 35 mm, and its depth at least 8 mm. The distance between the top of the
groove and the top of the element shall be at least 30 mm. The distance between the bottom of the groove and the
bottom of the element shall be at least 30 mm.
Typical shapes of longitudinal joints are given in Annex B.
4.3.2 Surface characteristics
Requirements given in 6.2.5 of EN 1992-1-1:2004 shall apply for hollow core slabs intended to be used with an in
situ topping.
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EN 1168:2005 (E)
4.3.3 Mechanical resistance
4.3.3.1 General
Complementary to 4.3.3 of EN 13369:2004 the following subparagraphs shall apply.
Where relevant, consideration should be given in the design to the effects of dynamic actions (e.g. impulse) during
transient situations. In the absence of a more rigorous analysis this may be allowed for by multiplying the relevant
static effects by an appropriate factor. For the effects of seismic actions, appropriate design methods should be
used.
Special rules for structures with hollow core elements are presented in annexes about load distribution (Annex C),
diaphragm action (Annex D), negative moments (Annex E), shear capacity of composite members (Annex F) and
design of connections (Annex H).
For confirmation of design model for shear resistance a test method is given in Annex J.
4.3.3.2 Verification by calculation
4.3.3.2.1 Resistance to splitting for prestressed hollow core slabs
Visible horizontal splitting cracks in the webs are not allowed.
Applying one of the requirements in a) or b) hereafter prevents splitting cracks:
a) for the web in which the highest splitting stress will be generated, or, for the whole section if the strands or
wires are essentially well distributed over the width of the element, the splitting stress σ shall satisfy the
sp
following condition:
σ ≤ f
sp ct
2,3
P 15 α + 0,07
o e
with σ = ×
sp
1,5
b e
w o
l
pt1
1 + 1,3 α + 0,1
e
e
o
(e - k)
o
and α =
e
h
where
f is the value of the tensile strength of the concrete deduced at the time that the prestress is released
ct
on the basis of tests;
P is the initial prestressing force just after release in the considered web;
o
b is the thickness of an individual web;
w
e is the eccentricity of the prestressing steel;
o
l is the lower design value of the transmission length;
pt1
k is the core radius taken equal to the ratio of the section modulus of the bottom fibre and the net area
of the cross section (W /A );
b c
b) a fracture-mechanics design shall prove that splitting cracks will not develop.
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EN 1168:2005 (E)
4.3.3.2.2 Shear and torsion capacity
4.3.3.2.2.1 General
Sections between the edge of a support and the section at a distance 0,5h from this edge, need not to be checked.
In case of flexible supports, the reducing effect of transversal shear stresses on the shear capacity shall be taken
into account.
4.3.3.2.2.2 Shear capacity – Torsion capacity
If a section is subjected simultaneously to shear and torsion and if more accurate methods are not available, the
shear capacity V shall be calculated as follows:
Rdn
V = V – V
Rdn Rd,c ETd
T Σb
Ed w
with V = ×
ETd
2b b−b
w w
where
V is the net value of the shear capacity;
Rdn
V is the design value of shear capacity according to 6.2.2 of EN 1992-1-1:2004;
Rd,c
V is the design value of acting shear force caused by the torsional moment;
ETd
T is the design value of the torsional moment in the considered section;
Ed
b is the width of the outermost web at the level of the elastic gravity line (see Figure 3).
w
Figure 3 — Eccentric shear force
4.3.3.2.3 Shear capacity of the longitudinal joints
Load distribution from an element to the adjacent element will cause vertical shear forces in the joint and the
elements at both sides of the joint.
The shear capacity in this case depends on the properties of the joint and of the elements.
This shear capacity v , expressed as resisting linear load, is the smaller value of the flange resistance v' or the
Rdj Rdj
joint resistance v :
Rdj
v' = 0,25 f Σh
Rdj ctd f
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SIST EN 1168:2005
EN 1168:2005 (E)
and
v"
= 0,15 (f h + f h )
Rdj ctdj j ctdt t
where
f is the design value of the tensile strength of the concrete in the elements;
ctd
f is the design value of the tensile strength of the concrete in the joints;
ctdj
f is the design value of the tensile strength of the concrete of the topping;
ctdt
Σh is the sum of the smallest thicknesses of the upper and lower flange and the scaled thickness of the
f
topping (see Figure 4);
h is the net height of the joint (see Figure 4);
j
h is the thickness of the topping (see Figure 4).
t
Figure 4 — Shear force in joints
The shear capacity V expressed as resisting concentrated load, shall be calculated as follows:
Rdj
V = v (a + h + h + 2 a )
Rdj Rdj j t s
where
v is the smaller value of v' or v ;
Rdj Rdj Rdj
a is the length of the load parallel to the joint ;
a is the distance between the centre of the load and the centre of the joint.
s
4.3.3.2.4 Punching shear capacity
In the absence of particular justifications, the punching shear capacity of slabs without topping V , in newtons,
Rd
expressed as resisting point load, shall be calculated as follows:
σ
cp
V =b h f 1 + 0,3 α
Rd eff ctd
f
ctd
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SIST EN 1168:2005
EN 1168:2005 (E)
l
x
with α = ≤ 1 according to 6.2.2 of EN 1992-1-1:2004
l
bpd
where
b is the effective width of the webs according to Figure 5 ;
eff
σ
is the concrete compressive stress at the centroidal axis due to prestressing.
cp
b = b + b + b b = b + b
eff w1 w2 w3 eff w1 w2
a) General situation b) Free edge of floor-bay
b = b + b + b b = b + b
eff w1 w2 w3 eff w1 w2
c) General situation with structural topping d) Free edge of floor-bay with structural topping
Figure 5 — Effective width
For concentrated loads of which more than 50 % is acting on outermost web (b in Figures 5 b) and 5 d)) of a free
w2
edge of a floor bay, the resistance resulting from the equation is applicable only if at least one strand or wire in the
outermost web and a transverse reinforcement are present. If one of these o
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