EN 16612:2019

SLOVENSKI STANDARD
01-februar-2020
Steklo v gradbeništvu - Določevanje bočne nosilnosti steklenih plošč z izračunom
Glass in building - Determination of the lateral load resistance of glass panes by
calculation
Glas im Bauwesen - Bestimmung des Belastungswiderstandes von Glasscheiben durch
Berechnung und Prüfung
Verre dans la construction - Détermination par calcul de la résistance des vitrages aux
charges latérales
Ta slovenski standard je istoveten z: EN 16612:2019
ICS:
81.040.20 Steklo v gradbeništvu Glass in building
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 16612
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2019
EUROPÄISCHE NORM
ICS 81.040.20
English Version
Glass in building - Determination of the lateral load
resistance of glass panes by calculation
Verre dans la construction - Determination de la Glas im Bauwesen - Bestimmung des
resistance des feuilles de verre par calcul et par essai Belastungswiderstandes von Glasscheiben durch
Berechnung und Prüfung
This European Standard was approved by CEN on 21 July 2019.

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 CEN-CENELEC Management Centre 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 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, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16612:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 7
4 Symbols and abbreviations . 8
5 Requirements . 13
5.1 Basis of determination of load resistance of glass . 13
5.2 Material partial factor . 14
5.3 Process of determining the load resistance of glass . 14
6 Mechanical and physical properties of glass . 14
6.1 Values . 14
6.2 Approximate values . 15
7 Actions . 15
7.1 Assumptions related to the actions and combinations of actions . 15
7.2 Combinations of actions . 15
8 Strength and stress . 16
8.1 Design value of bending strength for annealed glass. 16
8.2 Design value of bending strength for prestressed glass . 18
9 Calculation principles and conditions . 19
9.1 General method of calculation . 19
9.2 Calculation method for laminated glass and laminated safety glass . 22
9.3 Calculation method for insulating glass units . 22
Annex A (informative) Parameters . 23
Annex B (informative) Calculation formulae for stress and deflection for large deflections of
rectangular panes supported on all edges . 32
Annex C (informative) Calculation process for insulating glass units. 36
Annex D (informative) Simplified calculation method for laminated glass . 48
Bibliography . 52

European foreword
This document (EN 16612:2019) has been prepared by Technical Committee CEN/TC 129 “Glass in
Building”, the secretariat of which is held by NBN.
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 April 2020 and conflicting national standards shall be
withdrawn at the latest by April 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Introduction
This document gives a method of determining the lateral load resistance of linearly supported glass
elements.
The method of determining the load resistance of glass is in accordance with the principles of structural
Eurocode EN 1990: Basis of structural design. The actions are determined in accordance with the
structural Eurocode 1 series for actions on structures, e.g. EN 1991-1-1, EN 1991-1-3 and EN 1991-1-4,
including the National annexes. In the design processes, the reliability is part of national competency.
For that reason, this document foresees that, to conform with the rules applied by the Eurocodes, the
following parameters are subject to national determination:
— material partial factors, γ and γ ;
M;A M;v
— factors for the load duration, k ;
mod
— factor for stressed edges, k .
e
1 Scope
This document gives a method of determining the design value of the bending strength of glass. It gives
the general method of calculation, and guidance for lateral load resistance of linearly supported glazed
elements used as infill panels.
NOTE Examples of lateral loads are wind loads, snow loads, self weight of sloping glass, and cavity pressure
variations on insulating glass units.
This document gives recommended values for the following factors for glass as a material:
— material partial factors, γ and ;
M;A γM;v
— factors for the load duration, k ;
mod
— factor for stressed edges, k .
e
Most glass in buildings is used as infill panels. This document covers those infill panels that are in a
class of consequence lower than those covered in EN 1990, so proposed values for the partial load
factors, γ and γ , are given for these infill panels.
Q G
The action of cavity pressure variations on insulating glass units is not covered by Eurocodes, so this
document also gives proposed values of combination factors, ψ , ψ and ψ , for this action.
0 1 2
This document does not determine suitability for purpose. Resistance to lateral loads is only one part of
the design process, which could also need to take into account:
• in-plane loading, buckling, lateral torsional buckling, and shear forces,
• environmental factors (e.g. sound insulation, thermal properties),
• safety characteristics (e.g. fire performance, mode of breakage in relation to human safety,
security).
This document does not apply to channel shaped glass, glass blocks and pavers, or vacuum insulated
glass units.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 410, Glass in building — Determination of luminous and solar characteristics of glazing
EN 572-1, Glass in building — Basic soda-lime silicate glass products — Part 1: Definitions and general
physical and mechanical properties
EN 673, Glass in building — Determination of thermal transmittance (U value) — Calculation method
EN 1279-5, Glass in building — Insulating glass units — Part 5: Product standard
EN 1288-2, Glass in building — Determination of bending strength of glass — Part 2: Coaxial double ring
test on flat specimens with large test surface areas
EN 1288-3, Glass in building — Determination of the bending strength of glass — Part 3: Test with
specimen supported at two points (four point bending)
EN 1748-1-1, Glass in building — Special basic products — Borosilicate glasses — Part 1-1: Definition and
general physical and mechanical properties
EN 1748-2-1, Glass in building — Special basic products —Glass ceramics — Part 2-1: Definitions and
general physical and mechanical properties
EN 1863-1, Glass in building — Heat strengthened soda lime silicate glass — Part 1: Definition and
description
, Eurocode — Basis of structural design
EN 1990:2002
EN 1991-1-1, Eurocode 1: Actions on structures — Part 1-1: General actions — Densities, self-weight,
imposed loads for buildings
EN 1991-1-3, Eurocode 1: Actions on structures — Part 1-3: General actions - Snow loads
EN 1991-1-4, Eurocode 1: Actions on structures — Part 1-4: General actions - Wind actions
EN 12150-1, Glass in building — Thermally toughened soda lime silicate safety glass — Part 1: Definition
and description
EN 12337-1, Glass in building — Chemically strengthened soda lime silicate glass — Part 1: Definition and
description
EN 13024-1, Glass in building — Thermally toughened borosilicate safety glass — Part 1: Definition and
description
EN 14178-1, Glass in building — Basic alkaline earth silicate glass products — Part 1: Float glass
EN 14179-1, Glass in building — Heat soaked thermally toughened soda lime silicate safety glass — Part
1: Definition and description
EN 14321-1, Glass in building — Thermally toughened alkaline earth silicate safety glass — Part 1:
Definition and description
EN 14449, Glass in building — Laminated glass and laminated safety glass — Evaluation of
conformity/Product Standard
EN 15681-1, Glass in building — Basic alumino silicate glass products — Part 1: Definitions and general
physical and mechanical properties
EN 15682-1, Glass in building — Heat soaked thermally toughened alkaline earth silicate safety glass —
Part 1: Definition and description
EN 16613, Glass in building — Laminated glass and laminated safety glass — Determination of interlayer
mechanical properties
1 This document is impacted by the amendment EN 1990:2002/A1:2005 and the corrigendum
EN 1990:2002/A1:2005/AC:2010.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
infill panel
panel that closes openings in buildings but does not contribute to the stability of the load bearing
members
3.2
annealed glass
glass which has been treated during manufacture to minimise the residual stress in the glass, allowing it
to be cut by scoring and snapping
Note 1 to entry: Examples are float glass, drawn sheet glass, patterned glass and wired glass.
3.3
prestressed glass
glass which has been subjected to a strengthening treatment, by heat or chemicals, which induces a
compressive surface stress into the whole surface of the glass, balanced by a tensile stress within the
body of the glass
Note 1 to entry: Examples are thermally toughened safety glass, heat strengthened glass and chemically
strengthened glass.
3.4
enamelled glass
glass which has a ceramic frit applied to the surface, by e.g. painting or screen printing, which is
subsequently fired into the surface of the glass
Note 1 to entry: Examples are enamelled heat strengthened glass, enamelled toughened glass and enamelled
heat soaked toughened glass.
3.5
equivalent thickness (of laminated glass)
thickness calculated for laminated glass which, when used in place of the glass thickness in an
engineering formula, will result in a reasonably accurate determination of the deflection of and / or
stress in the laminated glass
3.6
lateral load resistance
resistance to forces applied normal to the glass surface (i.e. at right angles to it)
3.7
cavity pressure variation
pressure applied to the panes of insulating glass units due to the internal volume of the hermetically
sealed cavity or cavities being affected by changes in temperature and changes in the ambient
atmospheric pressure in service
3.8
altitude load
cavity pressure change solely resulting from a difference in altitude between the place of assembly
(sealing) and the place of use
4 Symbols and abbreviations
A Surface area of the pane (= a x b)
a Shorter dimension of the pane
a* Characteristic length of a double insulating glass unit
b Longer dimension of the pane
C Limiting design value of the relevant serviceability criterion
d
c Coefficient for the effect of altitude change on isochore pressure (=0,12 kPa/m)
H
c Coefficient for the effect of cavity temperature change on isochore pressure
T
(=0,34 kPa/K)
E Young’s modulus of glass
E Tensile modulus of an interlayer material
L
F Design value of the action
d
F Design value of the action on pane 1 of a double insulating glass unit
d;e
F Design value of the action on pane 2 of a double insulating glass unit
d;i
F Design value of the action on pane 1 of a triple insulating glass unit
d;1
F Design value of the action on pane 3 of a triple insulating glass unit
d;3
f Frequency (of vibration)
f
Characteristic value of the bending strength of prestressed glass
b;k
f Design value of bending strength for the surface of glass panes
g;d
f Characteristic value of the bending strength of annealed glass
g;k
g Self weight load
g Self weight load of pane 1
g Self weight load of pane 2
g Self weight load of pane 3
G Permanent action
G Shear modulus of an interlayer material
L
H Altitude
H Altitude of production of insulating glass unit
P
h Nominal thickness of the pane
h Nominal thickness of pane 1 of an insulating glass unit or ply 1 of a laminated glass
h Nominal thickness of pane 2 of an insulating glass unit or ply 2 of a laminated glass
h Nominal thickness of pane 3 of an insulating glass unit or ply 3 of a laminated glass
h External heat transfer coefficient
e
h
Equivalent thickness of a laminated glass for calculating out-of-plane bending
eq;w
deflection
h Equivalent thickness of a laminated glass for calculating out-of-plane bending stress
eq;σ
h Equivalent thickness of a laminated glass for calculating out-of-plane bending stress
eq;σ;j
of ply j
h
Internal heat transfer coefficient
i
h Nominal thickness of pane j of an insulating glass unit or ply j of a laminated glass
j
h Nominal thickness of pane k of an insulating glass unit or ply k of a laminated glass
k
h The distance of the mid-plane of the glass ply 1 from the mid-plane of the laminated
m;1
glass
h The distance of the mid-plane of the glass ply 2 from the mid-plane of the laminated
m;2
glass
h
The distance of the mid-plane of the glass ply 3 from the mid-plane of the laminated
m;3
glass
h The distance of the mid-plane of the glass ply j from the mid-plane of the laminated
m;j
glass
h The distance of the mid-plane of the glass ply k from the mid-plane of the laminated
m;k
glass
h Cavity heat transfer coefficient
s
h Cavity heat transfer coefficient - cavity 1
s1
h Cavity heat transfer coefficient - cavity 2
s2
J Variable used in calculations of cavity temperatures for triple glazed insulating glass
A
units
J Variable used in calculations of cavity temperatures for triple glazed insulating glass
B
units
J Variable used in calculations of cavity temperatures for triple glazed insulating glass
C
units
J Variable used in calculations of cavity temperatures for triple glazed insulating glass
D
units
k Coefficient used in the calculation of large deflection: stresses
k Coefficient used in the calculation of large deflection: deflections
k Coefficient used in the calculation of large deflection: volume changes
k Coefficient used in the calculation of insulating glass unit edge seal force
k Factor for edge strength
e
k Coefficient of class of consequence expressing the reduction of safety applicable to
FI
the secondary structures and infill panels compared to that applicable for the main
structures
k Factor for the load duration
mod
k Factor for the load duration of the dominant action in a load combination
mod;1
k Factor for the load duration when there are combined loads
mod;c
k Factor for the load duration of a permanent action in a load combination
mod;G
k Factor for the load duration of a non-dominant action in a load combination
mod;i
k Factor for the glass surface profile
sp
k
Factor for strengthening of prestressed glass
v
n coefficient used in the formula for static fatigue (stress corrosion) of glass. The
normally used value is 16.
p Pressure
p Isochore pressure for an insulating glass unit
p Isochore pressure for cavity 1 of an insulating glass unit
0;1
p Isochore pressure for cavity 2 of an insulating glass unit
0;2
p Meteorological air pressure (air pressure at sea level)
a
p
Average meteorological air pressure = 100 kN/m
a;m
p Isochore pressure due to the effect of change in cavity temperature and air pressure
C;0
p Externally applied uniformly distributed load on pane 1 of a triple insulating glass
ex;1
unit
p Externally applied snow load on pane 1 of a triple insulating glass unit
ex;1;S
p Externally applied wind load on pane 1 of a triple insulating glass unit
ex;1;W
p Externally applied uniformly distributed load on pane 3 of a triple insulating glass
ex;3
unit
p Isochore pressure due to the effect of change in altitude
H;0
p Meteorological air pressure (air pressure at sea level) at the time of production of
P
insulating glass unit
p Load partition for pane 1 of a triple insulating glass unit
res;1
p Load partition for pane 2 of a triple insulating glass unit
res;2
p Load partition for pane 3 of a triple insulating glass unit
res;3
p
Load partition of cavity pressure variation for pane k of a triple insulating glass unit
res;C;k
p Load partition of dead load for pane k of a triple insulating glass unit
res;G;k
p Load partition of snow + dead load for pane k of a triple insulating glass unit
res;S;k
p Load partition of wind + snow + dead load for pane k of a triple insulating glass unit
res;W;k
p* Non-dimensional uniformly distributed load
Q Single action or dominant action
k,1
Q
Actions which are not dominant
k,i
q Insulating glass unit edge seal force
e
R Design value of the resistance to the actions
d
s Nominal cavity width of a double glazed insulating glass unit
s Nominal cavity width of cavity 1 in a triple glazed insulating glass unit
s Nominal cavity width of cavity 2 in a triple glazed insulating glass unit
T Insulating glass unit cavity temperature
C
T Insulating glass unit cavity temperature - cavity 1
C;1
T
Insulating glass unit cavity temperature - cavity 2
C;2
T External air temperature
ext
T
Glass temperature of the central pane of a triple glazed insulating glass unit
g;cen
T Glass temperature of the outer pane of an insulating glass unit
g;ext
T Glass temperature of the inner pane of an insulating glass unit
g;int
T Internal (room) air temperature
int
T Temperature of production of insulating glass unit
P
t Load duration (in hours)
V Volume displaced due to the deflection of a pane
V
Nominal volume of cavity 1 in an insulating glass unit
pr;1
V Nominal volume of cavity 2 in an insulating glass unit
pr;2
V Nominal volume of cavity k in an insulating glass unit
pr;k
w Design value of deflection
d
w Maximum deflection calculated for the design load
max
z Coefficient used in the approximate calculation of k
1 4
z Coefficient used in the approximate calculation of k
2 1
z Coefficient used in the approximate calculation of k
3 1
z Coefficient used in the approximate calculation of k
4 1
+
Relative volume changes for the panes on either side of cavity 1 of a triple insulating
α α
,
1 1
glass unit
+
Relative volume changes for the panes on either side of cavity 2 of a triple insulating
α α
,
2 2
glass unit
+
Relative volume changes for the panes on either side of cavity k of a triple insulating
α , α
k k
glass unit
α Solar direct effective absorptance of the outer pane of an insulating glass unit
e1
α Solar direct effective absorptance of the second pane of an insulating glass unit
e2
α Solar direct effective absorptance of the third pane of an insulating glass unit
e3
β Factor used in calculating internal pressure differences in triple insulating glass
units
Δp Internal pressure difference for cavity 1 of a triple insulating glass unit
1;j
Δp Internal pressure difference for cavity 2 of a triple insulating glass unit
2;j
Δp Internal pressure difference due to cavity pressure variations for cavity i of a triple
C;i;j
insulating glass unit
Δp Internal pressure difference due to dead loads for cavity i of a triple insulating glass
G;i;j
unit
Δp Internal pressure difference for cavity i of a triple insulating glass unit
i;j
Δp Internal pressure difference due to snow + dead loads for cavity i of a triple
S;i;j
insulating glass unit
Δp Internal pressure difference due to wind + snow + dead loads for cavity i of a triple
W;i;j
insulating glass unit
δ Stiffness partition for pane 1 of a double insulating glass unit
δ Stiffness partition for pane 2 of a double insulating glass unit
ϕ Insulating glass unit factor for a double insulating glass unit
ϕ Insulating glass unit factor for cavity 1 of a triple insulating glass unit
ϕ Insulating glass unit factor for cavity 2 of a triple insulating glass unit
ϕ
Incident solar radiant flux
e
γ Partial factor
γ Partial factor for permanent actions, also accounting for model uncertainties and
G
dimensional variations
γ Material partial factor for annealed glass
M;A
γ Material partial factor for surface prestress
M;v
γ
Partial factor for variable actions, also accounting for model uncertainties and
Q
dimensional variations
λ
= a b
Aspect ratio of the pane ( )
μ Poisson number
ν Volume change of glass pane 1 when subjected to unit uniform pressure
p;1
ν Volume change of glass pane 2 when subjected to unit uniform pressure
p;2
ν Volume change of glass pane 3 when subjected to unit uniform pressure
p;3
ν Volume change of glass pane k when subjected to unit uniform pressure
p;k
ν Volume change of glass pane k+1 when subjected to unit uniform pressure
p;k+1
θ Temperature
ρ Glass density
σ Stress
σ Allowable stress
all
σ Allowable stress associated with load type i
all;i
σ Calculated stress from load type i
calc;i
σ Calculated stress from dead load
G
σ Maximum stress calculated for the design load
max
σ
Calculated stress from snow load
S
σ Calculated stress from wind load
W
ψ Combination factor
ψ Combination factors for the actions which are not dominant
ψ Factors for combination value of accompanying variable actions
0,i
ψ Combination factor for a frequent value of a variable action
Note 1 to entry: This value is determined - in so far as it can be fixed on statistical
bases - so that either the total time, within the reference period, during which it is
exceeded is only a small given part of the reference period, or the frequency of it
being exceeded is limited to a given value. It may be expressed as a determined part
of the characteristic value by using a factor ψ ≤ 1
ψ Combination factor for a quasi-permanent value of a variable action
Note 1 to entry: This value is determined so that the total period of time for which
it will be exceeded is a large fraction of the reference period. It may be expressed as
a determined part of the characteristic value by using a factor ψ ≤ 1
ψ Combination factor for a quasi-permanent value of a variable action
2,i
Note 1 to entry: This value is determined so that the total period of time for which
it will be exceeded is a large fraction of the reference period. It may be expressed as
a determined part of the characteristic value by using a factor ψ ≤ 1
2;i
ω Coefficient for the shear transfer of an interlayer in laminated glass
5 Requirements
5.1 Basis of determination of load resistance of glass
The process shall follow the principles of EN 1990: Eurocode – Basis of structural design.
The determination of actions shall be in accordance with the relevant parts of EN 1991-1-1,
EN 1991-1-3 and EN 1991-1-4. Where relevant or required, other codes shall also be taken into account.
5.2 Material partial factor
The proposed values of the material partial factor are given in Table 1.
Table 1 — Proposed values of the material partial factor
Ultimate limit state
a
γ = 1,8
Annealed glass
M;A
γ = 1,2
Surface prestress
M;v
a
The material partial factor for annealed glass is also applied to a component of the
bending strength of prestressed glass - see Formula (6).
Informative Annex A gives further explanations about the material partial factors.
5.3 Process of determining the load resistance of glass
The mechanical and physical properties of glass shall be determined in accordance with Clause 6.
The design value of the actions shall be determined in accordance with Clause 7.
The design value of bending strength for the glass, for the ultimate limit state and for the serviceability
limit state (if required), shall be determined in accordance with Clause 8.
For calculations, the principles and conditions shall be in accordance with Clause 9.
6 Mechanical and physical properties of glass
6.1 Values
The values of the mechanical and physical properties needed for calculation, such as Young's modulus
E, the Poisson number, μ, and the density of glass ρ, are specified in the following standards:
EN 572-1, EN 1748-1-1, EN 1748-2-1, EN 1863-1, EN 12150-1, EN 12337-1, EN 13024-1, EN 14178-1,
EN 14179-1, EN 14321-1, EN 14449, EN 15681-1, EN 15682-1.
NOTE The Poisson number, μ, for soda-lime silicate glass is given in EN 572-1 rounded to 0,2. For calculation
purposes it is more accurately taken as 0,23.
6.2 Approximate values
When (e.g. for assembling different glass materials) no distinction between the various differences in
mechanical and physical properties can be taken into account, or when it is not necessary, the following
values (for soda-lime-silicate glass) may be used for all glass types:
glass density ρ = 2 500 kg/m ;
Young’s modulus E = 70 000 MPa;
Poisson number μ = 0,23;
7 Actions
7.1 Assumptions related to the actions and combinations of actions
For actions and combinations of actions in the service limit state, as a function of the criteria, the
characteristic or the frequent combination applies (see EN 1990:2002, 6.5.3 a), 6.5.3 b), and 4.1.3).
For the combination of the actions in an ultimate limit state, the fundamental combination applies (see
EN 1990:2002, Clauses 6.4.3 and 4.1.3).
7.2 Combinations of actions
The values of the actions shall be determined in accordance with EN 1991-1-1, EN 1991-1-3, and
EN 1991-1-4.
The design value of the action (design load) shall be:
— for ultimate limit state:
FG=γ . ""+ γ .Q ""+ γψ Q (1)
∑
d G Q k ,1 Q 0,i ki,
i
— for irreversible characteristic serviceability limit state, which corresponds to the characteristic
combination:
F=G""++Q "" ψ Q (2)
d k ,1 ∑ 0,i ki,
i
— for reversible serviceability limit state, which corresponds to the frequent combination:
F = G"+"ψ .Q "+" ψ Q (3)
d 1 k ,1 ∑ 2,i k ,i
i
The proposed values of the partial load factors, γ, for infill panels are given in Table 2.
Table 2 — Proposed partial load factors
a a
γ γ
Q G
favourable unfavourable favourable unfavourable
Infill panel with class
of consequence lower 0 1,1 1,0 1,1
than CC1
a
The lower value is used when the action has a favourable effect in combination with other
actions. The higher value is used when the action is considered acting alone or has an
unfavourable effect in combination with other loads.
Load combination factors for actions covered by EN 1990, e.g. wind, snow and self-weight, should be
taken from Table A1.1 of EN 1990:2002.
The proposed values of the load combination factors, ψ, for cavity pressure variations are given in
Table 3.
Table 3 —Proposed load combination factors
Combination Infill panel
factor
Cavity pressure ψ 0,3
variations for insulating
ψ 0,3
glass units
ψ 0
The partial factors for actions given in Table 2 and the combination factors given in Table 3 are
specifically for the case of infill panels that are in a class of consequence lower than those covered in
EN 1990. For any other applications, the Eurocodes should be consulted.
Altitude loads should be taken as permanent loads.
Annex A gives further explanations about partial load factors.
8 Strength and stress
8.1 Design value of bending strength for annealed glass
8.1.1 Calculation formula
The design value of bending strength for annealed glass material, whichever composition, is
k k k f
e mod sp g;k
(4)
f =
g;d
γ
M ;A
8.1.2 Edge strength factor
Where glass edges are subjected to only low stresses in bending, for example as is generally the case in
a pane with all edges supported, then the value of k is taken as 1,0. Where glass edges are stressed in
e
bending, for example in pane with two opposite edges supported or with three edges supported, the
value of k can be lower than 1,0.
e
Annex A gives further explanations about the edge strength factor.
8.1.3 Glass surface profile factor
The factor for the glass surface profile is given in Table 4.
Table 4 — Factor for the glass surface profile
a
Factor for the glass surface profile k
Glass material
sp
(whichever glass composition)
c c
As produced Sandblasted
Float glass 1,0 0,6
Drawn sheet glass 1,0 0,6
b
(1,0) (0,6)
Enamelled float or drawn sheet glass
Patterned glass 0,75 0,45
b
(0,75) (0,45)
Enamelled patterned glass
Polished wired glass 0,75 0,45
Patterned wired glass 0,6 0,36
a
All coated glass, painted glass (not enamelled glass), mirror glass etc., where the applied material
does not affect the glass structure, can be treated the same as the substrate glass without the applied
material.
b
These glass types are not generally available as annealed glass, but the values of k are also needed
sp
in the formulae for prestressed glass (see 8.2).
c
For acid etched glass, the ‘as produced’ value of k should be used
sp
8.1.4 Factor for duration of load
The factor for the load duration of annealed glass is
−
(5)
k = 0,663t
mod
where
t is the load duration in hours.
For normal building loads, the factor k has a maximum value of k = 1 and a minimum value of
mod mod
k = 0,25.
mod
NOTE 1 For exceptional loads of very short duration, e.g. explosions, values of k greater than 1 can be used.
mod
Formula (5) can be considered valid for durations down to 20 msec.
Proposed values of k are given in Table 5.
mod
Table 5 — Proposed factors for load duration
Action Load duration k
mod
a
5 s (or less) 1,0
Wind gusts
b
Wind storm accumulative 0,74
10 min equivalent
c
Barrier personnel loads - normal duty 0,89
30 s
c
Barrier personnel loads - crowds 0,77
5 min
Maintenance loads 30 min 0,69
d
Snow 0,45
3 weeks
e
Cavity pressure variations on insulating glass 0,58
8 h
units
Dead load, self weight, altitude load on permanent (50 years) 0,29
insulating glass units
a
If dimensioning resistance against peak velocity wind pressure ( q z = C zq , load duration
( ) ( )
p eb
3 s), k = 1,0 should be used.
mod
b
The value of k = 0,74 is based on a cumulative equivalent duration of 10 min, considered
mod
representative of the effect of a storm which may last several hours. Higher values of k can be
mod
considered for wind.
c
The value of k = 0,89 is based on a personnel load of 30 s duration. Other values can be
mod
considered depending on the type of personnel load being evaluated and also the building use.
d
k = 0,45 can be considered representative for snow loads lasting between 5 days (k = 0,49)
mod mod
and 3 months (k = 0,41). Other values of k can be appropriate depending on local climate.
mod mod
e
k = 0,58 can be considered representative for cavity pressure variations lasting between 6 h
mod
(k = 0,59) and 12 h (k = 0,57). Other values of k can be appropriate depending on local
mod mod mod
climate.
Where loads with different durations need to be treated in combination, the proposed k for the load
mod
combination is the highest value from Table 5, which is associated with any of the loads in the
combination.
NOTE 2 For example, if glass is subject to wind, snow and self weight loads, the effects of a combination of
snow and self weight would be evaluated using a k of 0,45 and the effects of a combination of wind, snow and
mod
self weight loads would be evaluated using a k of 0,74 (or 1,0). All relevant combinations are to be checked.
mod
For specific further information about values of k and methods of treating combined loads, see
mod
Annex A.
8.2 Design value of bending strength for prestressed glass
8.2.1 Calculation formula
The design value of bending strength for prestressed glass material, whichever composition, is
k k f k ( f − f )
mod sp g;k v b;k g;k
f = + (6)
g;d
γ γ
M ;A M ;v
8.2.2 Characteristic bending strength
The values of characteristic bending strength for prestressed glass are given in Table 6.
Table 6 — Values of characteristic bending strength for prestressed glass
Glass material per Values for characteristic bending strength f for prestressed glass
b;k
product
processed from:
(whichever
thermally toughened safety glass heat chemically
composition)
to EN 12150-1, and heat soaked strengthened strengthened
thermally toughened safety glass glass to glass to
to EN 14179-1 EN 1863-1 EN 12337-1
2 2 2
float glass or drawn
120 N/mm 70 N/mm 150 N/mm
sheet glass
2 2 2
patterned glass
90 N/mm 55 N/mm 100 N/mm
2 2
enamelled float or
75 N/mm 45 N/mm
drawn sheet glass
2 2
enamelled
75 N/mm 45 N/mm
patterned glass
NOTE 1 The values for thermally toughened safety glass and heat soaked thermally toughened safety
glass can also be used for glass conforming to EN 13024-1, EN 14321-1 and EN 15682-1.
NOTE 2 The characteristic bending strength values in the table are the same as in the product
standards at the time of publication of this document. In the case of revision of the values in the product
standards, then the values in the product standards take precedence.
8.2.3 Strengthening factor
The presence of tong marks in vertically toughened glass reduces the effectiveness of the prestressing
locally compared with horizontally toughened glass which has no tong marks. The strengthening factor
for method of manufacture is given in Table 7.
Table 7 — Strengthening factor
Strengthening factor, k
Manufacturing process
v
Horizontal toughening
1,0
(or other process without the use of tongs or
other devices to hold the glass)
Vertical toughening
0,6
(or other process using tongs or other devices
to hold the glass)
9 Calculation principles and conditions
9.1 General method of calculation
9.1.1 Design load
The value of the design load, F , shall be determined in accordance with Clause 7.
d
Where there is no obvious design load, in order to ensure a reasonable amount of stiffness and strength
in any application, the glass should be able to resist a minimum unfactored short duration uniformly
distributed load of 0,4 kN/m .
9.1.2 Stress and deflection calculation
The design load shall be used for calculating the principal tensile stress or the principal tensile bending
stress in the glass and the deflection of the glass.
The method used for the determination of stress and deflection shall be an engineering formula or
method appropriate to the load distribution, the shape of the glass and the support conditions.
In general, the maximum stress, σ , and the maximum deflection, w , shall be calculated according
max max
to geometrically linear theory of plate bending. For glass panes simply supported on all edges where the
deflection induced by the actions exceeds half the glass thickness, geometrically linear theory of plate
bending may excessively overestimate the stresses and the maximum deflection. In this case the stress
distribution and the maximum deflection can be calculated according to geometrically nonlinear plate
bending theory. Annex B gives formulae for geometrically nonlinear plate bending theory calculations
for four-edge simply supported rectangular panes.
For laminated glass, the stress in each ply shall be calculated. For insulating glass units, the stress in
each pane shall be calculated. A method for determining the loads applied to each pane of an insulating
glass unit is given in Annex C.
9.1.3 Design value of bending strength
The design value of bending strength, f , shall be determined according to Clause 8. The value of the
g;d
load duration factor, k , used to calculate the design value of bending strength shall be appropriate to
mod
the anticipated duration of the single load or load combination.
9.1.4 Design value of deflection
There is no specific requirement of glass strength to limit the bending deflection of the glass under load.
EN 1279-5 suggests deflection limits for the supporting frames for insulating glass units in order to
minimize stresses on the edge seal, which may affect durability. Other standards or regulations may
require deflection limits for particular applications.
It should be ensured that glass deflections should be not so high that the glass can come away from its
fixings, either by limiting the deflection or by ensuring there is sufficient edge support to accommodate
it.
If required, the design value of deflection, w , will be in accordance with the appropriate standard.
d
Consideration should be given to ensuring the glass is not excessively flexible when subjected to applied
loads, as this can cause alarm to building users. In the absence of any specific requirement, deflections
shall be limited to span/65 or 50 mm, whichever is the lower value, where span is, for example:
— the length of the longer unsupported edge for 2 edge supported glass,
— the length of the unsupported edge for 3 edge supported glass,
— the shorter dimension of a 4 edge supported glass.
If deflection is not critical, larger design values may be considered.
9.1.5 Comparisons of stress and deflection
The maximum bending stress, σ , calculated for the design load or a combination of design loads shall
max
not exceed the design value of bending strength, f :
g;d
σ ≤ f (7)
max g;d
If there is a requirement for limitation of the glass deflection, the maximum deflection calculated for the
most onerous load condition, w , shall not exceed the design value of deflection, w :
max d
w ≤w (8)
max d
If there are combinations of loads to be considered, it may be necessary to perform the procedures in
9.1.1 to 9.1.5 more than once, taking alternative actions as the leading action, in order to determine the
most onerous condition. The most onerous condition is either:
• the highest value of the maximum stress, in relation to the design value of bending strength; or
• the largest value of maxim
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