SIST EN 1168:2005/kFprA3:2011
(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
SIST EN 1168:2005/kFprA3:2011
01-april-2011
0RQWDåQLEHWRQVNLL]GHONL9RWOHSORãþH
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
SIST EN 1168:2005/kFprA3:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN 1168:2005/kFprA3:2011
---------------------- Page: 2 ----------------------
SIST EN 1168:2005/kFprA3:2011
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.
---------------------- Page: 3 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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.
2
---------------------- Page: 4 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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.".
3
---------------------- Page: 5 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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
4
---------------------- Page: 6 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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;
5
---------------------- Page: 7 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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
0
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.
6
---------------------- Page: 8 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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)
2
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
7
---------------------- Page: 9 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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
8
---------------------- Page: 10 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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
2
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
9
---------------------- Page: 11 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
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 distance 0,5h from this edge (where h is the
depth of the section), need not to be checked.".
Update the figure numbering due to addition of Figure 3.
12 Modification to 4.3.3.2.2.2, Shear with torsion capacity
Replace the title and the whole subclause with the following: "
4.3.3.2.2.4 Shear capacity of elements subjected to torsion
If a section is subjected simultaneously to shear and torsion, the shear capacity V shall be calculated in the
Rdn
absence of particular justifications as follows:
V = V - V
Rdn Rd,c Etd
in which V is
Etd
T Σb
Ed w
V = × for hollow-core elements
Etd
2b (b − b )
w w
or
(3 +1,8×b/h)
V = T × for solid elements
Etd
Ed
b
where
V is the net value of the shear resistance, in newtons;
Rdn
V is the design value of shear resistance according to 6.2.2 of EN 1992-1-1:2004, in newtons;
Rd,c
V is the design value of acting shear force taking into account the torsional moment, in newtons;
ETd
T is the design value of the torsional moment in the considered section, in newtons millimetres;
Ed
b is the width of the outermost web at the level of the centroidal axis (see Figure 4), in millimeters;
w
Σb is the sum of all webs at the level of the centroidal axis, in millimeters.
w
10
---------------------- Page: 12 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
Figure 4 — Eccentric shear force".
13 Modification to 4.3.3.2.6, Load capacity of elements supported on three edges
Replace the third paragraph with the following:
The load capacity q , in newtons per millimeter, for imposed load per unit area which is the total load minus
k
the load due to the self weight of the elements, shall be calculated, in the serviceability limit state, as follows:
f W
ctk0,05 t
q =
k
2
0,06l
in which W is the lower value of
t
W = 2t (h - h )(b - b )
t f w
and
2
b h
W = ,
t
(3 + 1,8b / h)
where
W is the torsional section modulus of an element according to the elastic theory, in cubic millimetres;
t
t is the smallest of the values of h and b , in millimetres;
f w
h is the smallest value of the upper or lower thickness of the flange;
f
b is the thickness of the outermost web, in millimeters;
w
L is the length of the element.".
11
---------------------- Page: 13 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
14 Modification to 4.3.4.1, Resistance to fire
Replace the first sentence with the following:
"Complementary to EN 13369:2004, 4.3.4.1 to 4.3.4.3 the calculation method and tabulated data is given in
Annex G. In absence of national rules concerning shear capacity under fire conditions, additional rules can be
found in the Annex G.".
Replace the note with the following:
"NOTE The fire resistance given for a hollow core element (load bearing function) is valid when installed in a floor
structure with necessary tying system according to EN 1992-1-1:2004, unless additional measures are taken. For
separating function of hollow core slab floors, insulation (for minimum thickness see Annex G) and integrity (for joints see
EN 1992-1-2:2004, 4.6) are additionally required. The topping or screed cast directly on the precast unit may be taken into
account in the fire resistance of the floor for the separating function.".
15 Modification to Clause 5, Test methods
Add a new subclause: "
5.2 Tests on pre-stressing steel
In case of thermal pre-stressing, all additional tests described in Annex K shall apply.".
Update the numbering of the following clauses (automatically, not tagged):
5.2 Measuring of dimensions and surface characteristics
becomes:
5.3 Measuring of dimensions and surface characteristics
5.2.1 Element dimensions
becomes:
5.3.1 Element dimensions
5.2.1.1 Procedure
becomes:
5.3.1.1 Procedure
5.3 Weight of the products
becomes:
5.4 Weight of the products
12
---------------------- Page: 14 ----------------------
SIST EN 1168:2005/kFprA3:2011
EN 1168:2005/FprA3:2011 (E)
16 Modification to Clause 6, Evaluation of conformity
nd
Add after the 2 paragraph of 6.3 the following new paragraph:
"For inspection tests in case of thermal pre-stressing, specific additional rules are given in Annex K.".
17 Modifications to C.5 Load distribution factors for three or four supported edges
Replace the title and the whole subclause with the following: "
C.5 Load distribution factors for three or four supported edges
C.5.1 General
When, in addition to the two end supports of the elements, one or two lateral edges of the floor are supported,
the load distribution factors are given in the following clauses both for linear and point loads.
When determining the reaction forces, linear loads with a length greater than half the span should be
considered as linear loads. Linear loads with a length smaller than half the span should be considered as
linear loads if the centre of the load is at midspan, and as point loads if the centre of the load is not at
midspan.
C.5.2 Linear loads
In case of a linear load F of constant intensity and one supported lateral edge, the resultant F of the
lin,d R
reaction distributed in the lateral support is given by
F = q L = k F L (C.1)
R rev lin,d
where the distribution factor k is given in Figure C.5 as a function of the longitudinal span L, in m, and of the
distance s of the load from the nearest lateral support.
If the number n of the elements is greater than 5, the reaction given by Equation (C.1) should be multiplied by
(n −5) s
1−
50 b
where b is the width of the elements.
If both lateral edges of the floor are supported, the reaction given by Equation (C.1) should be multiplied by
nb − s
nb
If the distance s is greater than 4,5b, the reaction of the lateral support may be taken equal to zero.
C.5.3 Point loads
In case
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.