EN 1168:2005/FprA3
(Amendment)Precast concrete products - Hollow core slabs
Precast concrete products - Hollow core slabs
Amendments on shear verification, thermal prestressing method, slabs > 2400/1200, transverse load distribution, fire resistance, slabs with variable depth
Betonfertigteile - Hohlplatten
Produits préfabriqués en béton - Dalles alvéolées
Montažni betonski izdelki - Votle plošče
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2011
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Precast concrete products - Hollow core slabs
Betonfertigteile - Hohlplatten
Produits préfabriqués en béton - Dalles alvéolées
Ta slovenski standard je istoveten z: EN 1168:2005/FprA3
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.
EUROPEAN STANDARD
FINAL DRAFT
EN 1168:2005+A2:2009
NORME EUROPÉENNE
EUROPÄISCHE NORM
FprA3
February 2011
ICS 91.100.30
English Version
Precast concrete products - Hollow core slabs
Produits préfabriqués en béton - Dalles alvéolées Betonfertigteile - Hohlplatten
This draft amendment is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee
CEN/TC 229.
This draft amendment A3, if approved, will modify the European Standard EN 1168:2005+A2:2009. If this draft becomes an amendment,
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration.
This draft amendment was established by CEN 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 CEN-CENELEC Management Centre has
the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1168:2005/FprA3:2011: E
worldwide for CEN national Members.
Foreword
This document (EN 1168:2005/FprA3:2011) has been prepared by Technical Committee CEN/TC 229
“Precast concrete products”, the secretariat of which is held by AFNOR.
This document is currently submitted to the Unique Acceptance Procedure.
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.
1 Modification to the Foreword
Replace paragraph 13, referring to Eurocodes, with the following:
"Eurocodes are taken as a common reference for design aspects. The installation of some structural precast
concrete products is dealt with by EN 13670. In all countries it can be accompanied by alternatives for national
application.".
2 Modification to the Introduction
th
Add the following paragraph after the 4 paragraph:
"Special rules for pre-stressing by means of thermal pre-stressing are given in Annex K.".
3 Modifications to Clause 1, Scope
st th
Replace the 1 sentence of the 4 paragraph with the following:
"The elements have lateral edges with a grooved profile in order to make a shear key to transfer shear
through joints contiguous elements.".
Add after this paragraph the following new paragraph:
"To improve this action vertical grooves may be provided.".
st th
Add after the 1 sentence of the 5 paragraph:
"Fitting slabs (narrowed slab elements) and recesses to the hollow core slabs can be made during production
or afterwards. Hollow core slabs can have provisions for thermal activation, heating, cooling, sound insulation,
etc. Due to these provisions, the concrete temperature remains in it’s natural range.”.
th
Add after the 5 paragraph the following new paragraph:
"This European Standard also deals with solid slab elements used in conjunction with hollow core slabs and
manufactured by extrusion, slipforming or mouldcasting, equivalent to the manufacturing of hollow core slabs.
These solid slabs have the same overall cross-section as hollow core slabs, however without hollow cores.".
th
Replace the 6 paragraph with the following:
"The application of the standard is limited for prestressed elements to a maximum depth of 500 mm and for
reinforced elements to a maximum depth of 300 mm.
For both types, the maximum width without transverse reinforcement is limited to 1 200 mm and with
transverse reinforcement to 2 400 mm.".
4 Modification to Clause 2, Normative references
Add the following reference:
"EN ISO 15630-3, Steel for the reinforcement and prestressing of concrete — Test methods - Part 3:
Prestressing steel (ISO 15630-3:2010)".
5 Modifications to 3.1, Definitions
Replace Figure 1 in 3.1.1 with the following: "
Key
A hollow core slab
B solid slab
C combined slab
1 core
2 web
Figure 1 — Types of hollow core slabs (examples)".
Insert three new definitions after 3.1.1: "
3.1.2
solid slab
slab with the same overall cross-section as a hollow core slab where, during manufacturing no voids are made
(Figure 1 B). This slab is manufactured in the same manner (machine, bed, …) as hollow core slabs with
voids
NOTE Hollow core slabs where the voids are filled with concrete after manufacturing of the hollow core element can
not be considered as a solid slab.
3.1.3
combined slab
hollow core slab that has partially a solid cross section (Figure 1 C). The depth of the cross section may vary
over the length of the element
3.1.4
fitting slab
slab sawn from a standard slab with a width ≥ 250 mm with at least two webs".
Update the term numbers as follows:
3.1.2 core into 3.1.5 core
3.1.3 web into 3.1.6 web
3.1.4 lateral joint into 3.1.7 lateral joint
3.1.5 topping into 3.1.8 topping
3.1.6 screed into 3.1.9 screed
3.1.7 hollow core slab floor into 3.1.10 hollow core slab floor
3.1.8 composite hollow core slab floor into 3.1.11 composite hollow core slab floor
Add 3.1.12: "
3.1.12
solid slab floor
floor made of solid core slabs after the grouting of the joints".
Add 3.1.13: "
3.1.13
composite solid slab floor
solid slab floor complemented by a cast in situ topping".
6 Modification to 4.1.1.1, Maximum diameter of prestressing steel
Replace the text of the subclause with the following:
"The diameter of pre-stressing steel is limited to:
Class 1: Elements with pre-stressing steel with a maximum of 11 mm for wires and 16 mm for strands;
Class 2: Elements with thermal pre-stressed bars with a maximum of 16 mm.
The use of pre-stressing bars is only allowed in accordance with Annex K.".
7 Modification to 4.2.1.1.1, Longitudinal bars
Replace the existing text of c) with the following: "
c) in the outermost webs there shall be at least one bar, for solid slabs, the equivalent position shall be
considered;".
8 Modifications to 4.3.1.1.2, Tolerances for construction purposes
Replace the text of b) with the following: "
b) slab width:
general ± 5 mm;
in case of fitting slabs ± 25 mm;
Add d) as follows: "
d) length of protruding strands.
The minus deviation from the measured length of the protruding part of the protruding strand in regard to the
nominal (design) value:
10 mm.
This value may be increased with half of the actual deviation (positive) of the measured slab length (a)).".
9 Addition of 4.3.1.2.5 Vertical grooves shape
Add a new subclause 4.3.1.2.5: "
4.3.1.2.5 Vertical grooves shape
The shape of possible vertical grooves used to improve the diaphragm action shall be appropriate with regard
to the resistance of the grout against horizontal shear. A typical shape of vertical grooves is given in Annex B.
In any case vertical grooves shall not be compulsory for diaphragm action, but only an additional provision.".
10 Modification to 4.3.3.2.1, Resistance to spalling for prestressed hollow core slabs
Replace the definitions for P and b with the following: "
0 w
P is the initial prestressing force just after release in the considered web or the total prestressing force
of the slab in case of solid slabs;
b is the thickness of the individual web or the total width b of the slab in case of a solid slab;".
w
11 Modification to 4.3.3.2.2, Shear and torsion capacity
Replace the whole subclause with the following: "
4.3.3.2.2.1 General verification procedure
Shear failure of hollow-core slabs without shear reinforcement may occur in regions cracked by bending or in
regions uncracked by bending. If a flexural crack arises within the anchorage length of the reinforcement, an
anchorage failure can also occur. All the three failure modes shall be considered.
1) Shear resistance in cracked regions shall be calculated using EN 1992-1-1:2004, Expressions (6.2.a)
and (6.2.b).
2) Shear resistance in uncracked regions shall be calculated using EN 1992-1-1:2004, Expression (6.4),
taking into account, when relevant, the additional shear stresses due to the transmission of the
prestressing force and referring to the most unfavourable position in the cross section. A procedure
to apply this calculation is given in 4.3.3.2.2.2 and 4.3.3.2.2.3.
NOTE A guidance on the calculation of the additional shear stresses in the anchorage zones of prestressing tendons
can also be found in CEB-FIP Model Code 90, clause 6.9.12.
3) Resistance against anchorage failure shall be calculated following EN 1992-1-1:2004, 9.2.1.4.
In case of flexible supports, the reducing effect of transversal shear stresses on the shear resistance shall be
taken into account.
For hollow-core slabs deeper than 450 mm the shear strength, both for regions cracked and uncracked by
bending, shall be reduced by 10 % with respect to the equations and procedures quoted above.
4.3.3.2.2.2 Shear resistance in uncracked regions
Regions uncracked by bending are defined by a flexural tensile stress smaller than f /γ . Here the shear
ctk0,05 C
resistance shall be calculated with the following equation:
Ib ( y)
w
V = ()f +σ ( y) f −τ ( y)
Rdc ctd cp ctd cp
S ( y)
c
where
n
1 (Y − y)(Y −Yp ) M
c c t Ed
σ ( y) = + × P (l ) − ×()Y − y (positive if compressive)
cp ∑ t x c
A I I
t=1
n
1 A ( y) S ( y)×(Y −Yp ) dP (l )
c c c t t x
τ ( y) = × − + Cp ( y) ×
cp ∑ t
b ( y) A I dx
t=1
w
This equation shall be applied with reference to the critical points of a straight line of failure rising from the
edge of the support with an angle β = 35° with respect to the horizontal axis. The critical point is the point on
the quoted line where the result of the expression of V is the lowest.
Rd,c
Key
1 line of failure
2 height of centroidal axis
3 considered cross-section
4 forces in considered cross-section
Figure 3 a) Line of failure Figure 3 b) Forces and moments in
considered cross-section
Figure 3 — Shear structure in uncracked regions
The definition of symbols is given here below.
I is the second moment of area of the cross section
b (y) is the web width at the height y
w
Y is the height of the centroidal axis
c
S (y) is the first moment of the area above height y and about the centroidal axis
c
y
is the height of the critical point on the line of failure
l is the distance of the considered point on the line of failure from the starting point of the
x
transmission length (= x)
σ (y) is the concrete compressive stress at the height y and distance l
cp x
n is the number of tendon layers
A is the fictive cross section surface
P (l ) is the prestressing force in the considered tendon layer at distance l . The transfer of prestress
t x x
shall be taken into account according to EN 1992-1-1:2004, 8.10.2.2
M
is the bending moment due to the vertical load
Ed
is the concrete shear stress due to transmission of prestress at height y and distance l
τ (y)
cp x
A (y) is the area above height y
c
Cp (y) is a factor taking into account the position of the considered tendon layer
t
Cp = -1 when y ≤ Yp
t t
Cp = 0 when y > Yp
t t
Yp is the height of the position of considered tendon layer
t
4.3.3.2.2.3 Simplified expression
As an alternative to the above equation, the following simplified equation may be applied
Ib
w
V = ϕ ()f +βασ f
Rdc ctd l cp ctd
S
where
I is the second moment of area;
S is the first moment of area above and about the centroidal axis
b is the width of the cross-section at the centroidal axis,
w
α = l / l is the degree of prestressing transmission (α ≤ 1,0);
ℓ x pt2 I
l is the distance of the considered section from the starting point of transmission length;
x
l upper value of transmission length (see EN 1992-1-1:2004, Expression (8.18));
pt2
σ = N /A is the full concrete compressive stress at the centroidal axis,
cp Ed
f = f /γ is the design value of tensile strength of concrete;
ctd ctk0,05 c
φ = 0,8 reducing factor;
β = 0,9 reducing factor referred to transmission length.
Sections between the edge of the support and the section at a di
...
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