FprEN 1994-1-2
(Main)Eurocode 4 - Design of composite steel and concrete structures - Part 1-2: Structural fire design
Eurocode 4 - Design of composite steel and concrete structures - Part 1-2: Structural fire design
(1) EN 1994-1-2 gives rules for the design of steel-concrete composite structures for the accidental design situation of fire exposure. It only identifies differences from, or supplements to, rules for normal temperature design.
(2) EN 1994-1-2 only applies to structures, or parts of structures, that are within the scope of EN1994-1-1 and are designed accordingly.
Eurocode 4 - Bemessung und Konstruktion von Verbundtragwerken aus Stahl und Beton - Teil 1-2: Tragwerksbemessung für den Brandfall
(1) EN 1994 1 2 enthält Regeln für die Bemessung und Konstruktion von Verbundtragwerken aus Stahl und Beton für die außergewöhnliche Bemessungssituation des Brandfalls. EN 1994 1 2 legt ausschließlich Unterschiede oder Ergänzungen zu den Bemessungsregeln für Normaltemperatur fest.
(2) EN 1994 1 2 gilt ausschließlich für Tragwerke oder Teiltragwerke, die in den Anwendungsbereich von EN 1994 1 1 fallen und dementsprechend bemessen werden.
1.2 Voraussetzungen
(1) Die in EN 1990 angegebenen Voraussetzungen gelten gemeinsam mit den folgenden:
die Festlegung des maßgebenden Bemessungsbrandfalls erfolgt durch angemessen qualifiziertes und erfahrenes Personal oder ist durch die maßgebende nationale Vorschrift vorgegeben;
jede bei der Bemessung berücksichtigte Brandschutzmaßnahme wird angemessen gewartet.
Eurocode 4 - Calcul des structures mixtes acier-béton - Partie 1-2 : Calcul du comportement au feu
1.1 Domaine d'application du prEN 1994-1-2
(1) La prEN 1994-1-2 donne des règles de calcul des ouvrages mixtes acier-béton pour la situation accidentelle d'exposition au feu. Elle identifie uniquement les différences avec les règles de calcul à température normale, ou lui apporte des compléments.
(2) La prEN 1994-1-2 s'applique aux structures, ou parties de structures, relevant du domaine d’application de l'EN 1994 1 1 et conçues en conséquence.
1.2 Hypothèses
(1) Les hypothèses de l'EN 1990 s'appliquent, ainsi que ce qui suit :
- le choix du scénario d’incendie de calcul pertinent est fait par un personnel possédant une qualification et une expérience appropriées, ou est indiqué par la règlementation nationale concernée ;
- toute mesure de protection contre l'incendie prise en compte dans le calcul fera l’objet d’une maintenance adéquate.
Evrokod 4 - Projektiranje sovprežnih konstrukcij iz jekla in betona – 1-2. del: Požarnoodporno projektiranje
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 1994-1-2:2024
01-junij-2024
Evrokod 4 - Projektiranje sovprežnih konstrukcij iz jekla in betona – 1-2. del:
Požarnoodporno projektiranje
Eurocode 4 - Design of composite steel and concrete structures - Part 1-2: Structural fire
design
Eurocode 4 - Bemessung und Konstruktion von Verbundtragwerken aus Stahl und Beton
- Teil 1-2: Tragwerksbemessung für den Brandfall
Eurocode 4 - Calcul des structures mixtes acier-béton - Partie 1-2 : Calcul du
comportement au feu
Ta slovenski standard je istoveten z: prEN 1994-1-2
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
91.010.30 Tehnični vidiki Technical aspects
91.080.13 Jeklene konstrukcije Steel structures
91.080.40 Betonske konstrukcije Concrete structures
oSIST prEN 1994-1-2:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 1994-1-2:2024
oSIST prEN 1994-1-2:2024
DRAFT
EUROPEAN STANDARD
prEN 1994-1-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2024
ICS 13.220.50; 91.010.30; 91.080.13; 91.080.40 Will supersede EN 1994-1-2:2005
English Version
Eurocode 4 - Design of composite steel and concrete
structures - Part 1-2: Structural fire design
Eurocode 4 ¿ Calcul des structures mixtes acier-béton ¿ Eurocode 4: Bemessung und Konstruktion von
Partie 1-2 : Calcul du comportement au feu Verbundtragwerken aus Stahl und Beton - Teil 1-2:
Allgemeine Regeln Tragwerksbemessung für den
Brandfall
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 250.
If this draft becomes a European Standard, 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.
This draft European Standard 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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye 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
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1994-1-2:2024 E
worldwide for CEN national Members.
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Contents Page
European foreword . 6
0 Introduction . 7
1 Scope . 10
Scope of prEN 1994-1-2 . 10
Assumptions . 10
2 Normative references . 10
3 Terms, definitions and symbols . 10
Terms and definitions . 10
Symbols and abbreviations . 12
Symbols . 12
Latin lower-case letters . 14
Additional symbols used in Annex A of prEN 1994-1-2 . 19
Additional symbols used in Annex B of prEN 1994-1-2 . 19
Additional symbols used in Annex C of prEN 1994-1-2 . 20
Additional symbols used in Annex D of prEN 1994-1-2 . 20
Additional symbols used in Annex E of prEN 1994-1-2 . 21
Additional symbols used in Annex F of prEN 1994-1-2 . 22
Additional symbols used in Annex G of prEN 1994-1-2 . 23
Additional symbols used in Annex H of prEN 1994-1-2 . 24
Additional symbols used in Annex I of prEN 1994-1-2. 25
4 Basis of design . 26
General. 26
Nominal fire exposure . 26
Physically based fire exposure . 27
Actions . 27
Design values of material properties . 27
Verification methods . 28
Member analysis . 28
Analysis of parts of the structures . 29
Global structural analysis . 29
5 Material properties . 29
General. 29
Thermal properties . 30
Carbon steel . 30
Concrete . 31
Fire protection materials . 34
Mechanical properties . 34
Carbon steel . 34
Concrete . 38
6 Tabulated design data . 41
General. 41
Beams . 41
Columns . 44
General. 44
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Composite columns made of totally encased steel sections . 45
Composite columns made of partially encased steel sections . 46
Composite columns comprising concrete filled hollow sections . 47
7 Simplified design methods . 48
General . 48
General rules for composite slabs and composite beams . 48
Composite slabs . 49
Unprotected composite slabs . 49
Protected composite slabs . 50
Composite beams . 50
Thermal analysis . 50
Mechanical analysis . 54
Composite columns . 63
General . 63
Partially encased steel sections . 65
Unprotected concrete filled hollow steel sections . 65
Protected concrete filled hollow steel sections . 65
8 Advanced design methods . 66
General . 66
Thermal analysis . 66
Mechanical analysis . 66
Validation . 67
9 Detailing . 67
General . 67
Composite beams . 68
Composite beams comprising steel beams with partial encasement . 68
Composite shallow floor beams . 69
Composite columns . 70
Composite columns comprising partially encased steel sections . 70
Composite columns comprising concrete filled hollow sections . 71
Connections between composite beams and columns . 72
General . 72
Connections between composite beams and composite columns comprising steel
sections encased in concrete . 73
Connections between composite beams and composite columns with partially
encased steel sections . 73
Connections between composite beams and composite columns comprising concrete
filled hollow sections . 74
(normative) Strain-hardening of structural steel at elevated temperatures . 76
Use of this annex . 76
Scope and field of application . 76
Stress-strain relationships at elevated temperatures for structural steel . 76
(informative) Model for the calculation of the fire resistance of unprotected
composite slabs . 79
Use of this annex . 79
Scope and field of application . 79
Fire resistance with respect to thermal insulation . 79
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Calculation of the sagging moment of resistance M . 81
fi,Rd+
-
Calculation of the hogging moment resistance M . 84
Rd,fi
Effective thickness of a composite slab . 87
(normative) Model for the calculation of the sagging and hogging moment
resistances of a steel beam connected to a concrete slab and exposed to fire from
underneath . 88
Use of this annex . 88
Scope and field of application . 88
+
Calculation of the sagging moment resistance M . 88
Rd,fi
Calculations of the hogging moment resistance M . 90
Rd,fi-
Local resistance at supports . 91
Vertical shear resistance . 92
(normative) Model for the calclulation of the bending moment resistances of a
partially encased steel beam connected to a concrete slab and exposed to fire . 93
Use of this annex . 93
Scope and field of application . 93
Reduced cross-section for sagging moment resistance 𝑴𝑴Rd,fi + . 94
Reduced cross-section for hogging moment resistance M - . 98
Rd,fi
(normative) Model for the calculation of the axial buckling resistance about the
weak axis of a partially encased composite column exposed to fire . 100
Use of this annex . 100
Scope and field of application . 100
General. 101
Flanges of the steel section . 101
Web of the steel section . 102
Concrete . 103
Reinforcing bars . 104
Calculation of the acial buckling load at elevated temperatures . 105
Eccentricity of loading . 106
(normative) Simple caculation model for concrete filled hollow sections exposed to
the standard temperature-time curve . 107
Use of this annex . 107
Scope and field of application . 107
Steps . 108
Temperature distribution . 108
Design axial buckling load at elevated temperature . 110
Eccentricity of loading . 113
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(normative) Simple calculation method for fire resistance of steel and concrete
composite floors under tensile membrane action. 114
Use of this annex . 114
Scope and field of application . 114
General rules . 114
Temperature distribution . 116
Calculation of floor loadbearing capacity under tensile membrane action . 116
Detailing . 123
(normative) Calculation of the sagging moment of resistance M of a shallow
fi,Rd+
floor beam exposed to fire. 125
Use of this annex . 125
Scope and field of application . 125
Calculation of the sagging moment resistance M . 127
Rd,fi+
Protected shallow floor beams . 131
(normative) Beams with large web openings exposed to fire . 133
Use of this annex . 133
Scope and field of application . 133
Thermal response . 133
Mechanical response . 133
Bibliography . 135
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European foreword
This document (prEN 1994-1-2:2024) has been prepared by Technical Committee CEN/TC 250
“Structural Eurocodes”, the secretariat of which is held by BSI. CEN/TC 250 is responsible for all
Structural Eurocodes and has been assigned responsibility for structural and geotechnical design matters
by CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1994-1-2:200 and its amendments and corrigenda.
The first generation of EN Eurocodes was published between 2002 and 2007. This document forms part
of the second generation of the Eurocodes, which have been prepared under Mandate M/515 issued to
CEN by the European Commission and the European Free Trade Association.
The Eurocodes have been drafted to be used in conjunction with relevant execution, material, product
and test standards, and to identify requirements for execution, materials, products and testing that are
relied upon by the Eurocodes.
The Eurocodes recognize the responsibility of each Member State and have safeguarded their right to
determine values related to regulatory safety matters at national level through the use of National
Annexes.
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0 Introduction
0.1 Introduction to the Eurocodes
The Structural Eurocodes comprise the following standards generally consisting of a number of Parts:
EN 1990, Eurocode — Basis of structural and geotechnical design
EN 1991, Eurocode 1 — Actions on structures
EN 1992, Eurocode 2 — Design of concrete structures
EN 1993, Eurocode 3 — Design of steel structures
EN 1994, Eurocode 4 — Design of composite steel and concrete structures
EN 1995, Eurocode 5 — Design of timber structures
EN 1996, Eurocode 6 — Design of masonry structures
EN 1997, Eurocode 7 — Geotechnical design
EN 1998, Eurocode 8 — Design of structures for earthquake resistance
EN 1999, Eurocode 9 — Design of aluminium structures
New parts are under development, e.g. Eurocode for design of structural glass
The Eurocodes are intended for use by designers, clients, manufacturers, constructors, relevant
authorities (in exercising their duties in accordance with national or international regulations), educators
software developers and committees drafting standards for related product, testing and execution
standards.
NOTE Some aspects of design are most appropriately specified by relevant authorities or, where not specified,
can be agreed on a project-specific basis between relevant parties such as designers and clients. The Eurocodes
identify such aspects making explicit reference to relevant authorities and relevant parties.
0.2 Introduction to EN 1994 (all parts)
EN 1994 applies to the design of steel and concrete composite structures in buildings and civil
engineering works. It complies with the principles and requirements for the safety and serviceability of
structures, the basis of their design and verification that are given in EN 1990, Basis of structural and
geotechnical design.
EN 1994 is concerned only with the requirements for resistance, serviceability, durability and fire
resistance of steel structures. Other requirements, e.g. concerning thermal or sound insulation, are not
covered.
EN 1994 is subdivided in various parts:
EN 1994-1-1, Eurocode 4 — Design of composite steel and concrete structures — Part 1-1: General rules
and rules for buildings;
EN 1994-1-2, Eurocode 4 — Design of composite steel and concrete structures — Part 1-2: Structural fire
design;
EN 1994-2, Eurocode 4 — Design of composite steel and concrete structures — Part 2: Bridges.
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0.3 Introduction to prEN 1994-1-2
prEN 1994-1-2 describes the principles, requirements and rules for the structural design of steel and
concrete composite buildings exposed to fire.
prEN 1994-1-2 is intended for clients (e.g. for the formulation of their specific requirements), designers,
contractors and relevant authorities.
The general objectives of fire protection are to limit risks with respect to the individual and society,
neighbouring property and where required, environment or directly exposed property, in the case of fire.
The parts of the Structural Eurocodes relating to fire deal with specific aspects of passive fire protection
in terms of designing structures and parts for adequate loadbearing resistance and for limiting fire spread
as relevant.
Required functions and levels of performance can be specified either in terms of nominal (standard) fire
resistance rating, generally given in national fire regulations or by referring to fire safety engineering for
assessing passive and active measures, see EN 1991-1-2.
Supplementary requirements concerning, e.g.:
the possible installation and maintenance of sprinkler systems;
conditions on occupancy of building or fire compartment; and
the use of approved insulation and coating materials, including their maintenance
are not given in this standard because they are subject to specification by the competent authority.
0.4 Verbal forms used in the Eurocodes
The verb “shall" expresses a requirement strictly to be followed and from which no deviation is permitted
in order to comply with the Eurocodes.
The verb “should” expresses a highly recommended choice or course of action. Subject to national
regulation and/or any relevant contractual provisions, alternative approaches could be used/adopted
where technically justified.
The verb “may" expresses a course of action permissible within the limits of the Eurocodes.
The verb “can" expresses possibility and capability; it is used for statements of fact and clarification of
concepts.
0.5 National Annex for prEN 1994-1-2
National choice is allowed in this standard where explicitly stated within notes. National choice includes
the selection of values for Nationally Determined Parameters (NDPs).
The national standard implementing prEN 1994-1-2 can have a National Annex containing all national
choices that relate to the design of buildings and civil engineering works constructed in the relevant
country.
When no national choice is given, the default choice given in this standard is to be used.
When no national choice is made and no default is given in this standard, the choice can be specified by a
relevant authority or, where not specified, agreed for a specific project by the relevant parties.
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National choice is allowed in prEN 1994-1-2 through notes to the following clauses:
4.5(1) 4.7(2) G.2(1)
National choice is allowed in prEN 1994-1-2 on the application of the following informative annex:
Annex B
The National Annex can contain, directly or by reference, non-contradictory complementary information
for ease of implementation, provided it does not alter any provisions of the Eurocodes.
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1 Scope
Scope of prEN 1994-1-2
(1) prEN 1994-1-2 gives rules for the design of steel-concrete composite structures for the accidental
design situation of fire exposure. It only identifies differences from, or supplements to, rules for normal
temperature design.
(2) prEN 1994-1-2 only applies to structures, or parts of structures, that are within the scope of
EN 1994-1-1 and are designed accordingly.
Assumptions
(1) The assumptions of EN 1990 apply, along with the following:
The choice of the relevant design fire scenario is made by appropriate qualified and experienced
personnel or is given by the relevant national regulation;
Any fire protection measure taken into account in the design will be adequately maintained.
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 dates references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including amendments) applies
NOTE See the Bibliography for a list of other documents cited that are not normative references, including those
referenced as recommendations (i.e. in ‘should’ clauses), permissions (‘may’ clauses), possibilities (‘can’ clauses),
and in notes.
EN 1990, Eurocode — Basis of structural and geotechnical design
EN 1991 (all parts), Eurocode 1 — Actions on structures
FprEN 1991-1-2:2023, Eurocode 1 — Actions on structures — Part 1-2: Actions on structures exposed to
fire
EN 1992-1-1, Eurocode 2 — Design of concrete structures — Part 1-1: General rules and rules for buildings,
bridges and civil engineering structures
EN 1993-1-1:2022, Eurocode 3 — Design of steel structures — Part 1-1: General rules and rules for
buildings
prEN 1994-1-1:2024, Eurocode 4 — Design of composite steel and concrete structures — Part 1-1: General
rules and rules for buildings
3 Terms, definitions and symbols
Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1990 and EN 1991-1-2 and the
following apply.
3.1.1
axis distance
distance between the centre of the reinforcing bar and the nearest edge of concrete
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3.1.2
critical temperature of reinforcement
temperature of reinforcement at which loadbearing failure of the element is expected to occur at a
given stress
3.1.3
critical temperature of structural steel element
temperature for a given load level, at which failure is expected to occur in a structural steel element
assuming a uniform temperature distribution
3.1.4
effective cross-section
cross-section of the member in structural fire design used in the effective cross-section method
Note 1 to entry: It is obtained by removing parts of the cross-section with assumed zero strength and stiffness.
3.1.5
failure time of fire protection system
duration of protection of member against direct fire exposure (e.g. when the fire protective sheathing or
other protection fall off the composite member, or when a structural member initially protecting the
member fails due to collapse, or when the protection from another structural member is no longer
effective due to excessive deformation)
3.1.6
fire protection material
any material or combination of materials applied to a structural member for the purpose of increasing
its fire resistance
3.1.7
maximum stress level
for a given temperature, the stress level at which the stress-strain relationship of steel is truncated
to provide a yield plateau
3.1.8
part of structure
isolated part of a structure with appropriate support and boundary conditions
3.1.9
protected members
members for which measures are taken to reduce the temperature rise in the member due to fire
3.1.10
section factor
for a steel member, the ratio between the exposed surface area and the volume of steel; for an enclosed
member, the ratio between the internal surface area of the exposed encasement and the volume of steel
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Symbols and abbreviations
For the purposes of this document, the following symbols apply.
Symbols
Latin upper-case letters
Symbol Definition
A cross-sectional area
Ac cross-sectional area of concrete part
A cross-sectional area of a steel flange
f
area of part i of the cross-section or exposed surface area of part i
A
i
of the steel cross-section per unit length
A Reduced area of part i of the cross-section at temperature θ
i,θ
section factor of part i of the steel cross-section (non-protected
A / V
i i
member)
area of the inner surface of the fire protection material per unit
A
p
length of the steel beam
A / V section factor of the steel cross-section with box protection
p
area of the inner surface of the fire protection material per unit
A
p,i
length of part i of the steel member
A / V section factor of part i of the steel cross-section
p,i i
A cross-sectional area of the reinforcing bars
s
E integrity criterion
characteristic value for the modulus of elasticity of structural steel
E
a
at 20 °C
characteristic value for the slope of the linear elastic range of the
stress-strain relationship of structural steel at elevated
E
a,θ
temperatures
characteristic value for the secant modulus of concrete in the fire
E
c,sec, θ
situation, given by f divided by ε
c,θ cu,θ
E design effect of actions for normal temperature design
d
design effect of actions in the fire situation, assumed to be time
Ed,fi
independent
(EI) effective flexural stiffness in the fire situation
eff,fi
E characteristic value for the modulus of elasticity at 20 °C
k
characteristic value for the modulus of elasticity of modulus of
E
s
elasticity of reinforcing bars at 20 °C
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characteristic value for the slope of the linear elastic range of the
E stress-strain relationship of reinforcing steel at elevated
s,θ
temperatures
F tensile force in the steel section
a
F compressive force in the slab
c
HC hydrocarbon fire exposure curve
I thermal insulation criterion
second moment of area of the partially reduced part i of the cross-
I section for bending around the weak or strong axis in the fire
i,θ
situation
L system length of a column in the relevant storey
LC lightweight concrete
design value of the sagging or hogging moment resistance in the
MRd,fi+; MRd,fi-
fire situation
M , design moment resistance in the fire situation at time t
Rd fi,t
NC normal weight concrete
N elastic critical load in the fire situation
fi,cr
design value of the plastic resistance to axial compression in the
N
pl,Rd,fi
fire situation
value of N when the factors γ , γ and γ are taken as
pl,Rd,fi M,fi,a M,fi,s M,fi,c
N
pl,R,fi
1,0
design value of the resistance of a member in axial compression in
N
Rd,fi
the fire situation
design shear resistance of a shear connector at normal
P
Rd
temperature.
P design shear resistance of a shear connector in the fire situation
Rd,fi
R Load bearing criterion
R30, R60,
a member complying with the loadbearing criterion for 30, 60, 90,
R90, R120,
120 or 180 minutes in standard fire exposure
R180
R design resistance for normal temperature
d
R design resistance in the fire situation, at time t
d,fi,t
V volume of part i of the steel cross-section per unit length
i
design values of mechanical (strength and stiffness) material
X
d,fi
properties in the fire situation
characteristic value of a strength or stiffness property for normal
X
k
temperature
characteristic value of a strength or stiffness property in the fire
Xk, θ
situation
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Latin lower-case letters
a throat thickness of weld
w
b width
b width of the bottom flange of the steel section
b width of the top flange of the steel section
depth of the composite column made of a totally encased section or
b
c
width of concrete partially encased steel beams
b effective width of the concrete slab
eff
c concrete cover from edge of concrete to border of structural steel
c specific heat of steel
a
c specific heat of concrete
c
c specific heat of the fire protection material
p
diameter of the composite column made of concrete filled circular
hollow section or diameter of the studs welded to the web of the steel
d
section
d thickness of the fire protection material
p
e thickness of hollow section
e thickness of the bottom flange of the steel section
e thickness of the top flange of the steel section
e thickness of the flange of the steel section
f
e thickness of the bottom plate of a shallow floor beam (type A)
p
e thickness of the web of the steel section
w
ef external fire exposure curve
f proportional limit of structural steel in the fire situation
ap,θ
ultimate tensile strength of structural steel or steel for stud
f
au,θ
connectors in the fire situation, allowing for strain-hardening
maximum stress level or effective yield strength of structural steel in
f
ay,θ
the fire situation
maximum stress level or effective yield strength of part i of the steel
f
ay,θ,i
section in the fire situation
f effective yield strength of structural steel at critical temperature θ
ay,θcr cr
characteristic or nominal value for the yield strength of structural
f
ay
steel at 20 °C
characteristic value of the compressive cylinder strength of concrete
f
ck
at 28 days and at 20 °C
characteristic value of the compressive cylinder strength of part j of
f
ck,j
the concrete at 28 days and at 20 °C
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characteristic value for the compressive cylinder strength of concrete
f
c,θ
at temperature θ
characteristic value for the compressive cylinder strength of concrete
f
c,θ,20 °C heated to a maximum temperature θc,max and having cooled down to
20 °C
characteristic value for the compressive cylinder strength of concrete
f
c,θmax
in the fire situation at maximum temperature θ
max
f characteristic value of strength of the material
k
characteristic or nominal value for the yield strength of a reinforcing
f
sy
bar at 20 °C
f proportional limit of reinforcing steel in the fire situation
sp,θ
maximum stress level or effective yield strength of reinforcing steel
f ,
sy θ
in the fire situation
nominal yield strength f for the elemental area A taken as positive
y i
f on the compression side of the plastic neutral axis and negative on
y,i
the tension side
h depth or height of the steel section
h height of the concrete part of a composite slab above the sheeting
h height of the concrete part of a composite slab within the sheeting
h thickness of the screed situated on top of the concrete
thickness of the concrete slab or depth of the composite column made
h
c
of a totally encased section
h effective thickness of a composite slab
eff
height reduction of the encased concrete between the flanges in the
h
fi
fire situation
h design value of the net heat flux per unit area
net
h design value of the net heat flux per unit area by convection
net,c
h design value of the net heat flux per unit area by radiation
net,r
h height of the stud welded on the web of the steel section
v
h height of the web of the steel section
w
reduction factor for the compressive strength of concrete giving the
k
c,θ
strength at elevated temperature f
c,θ
reduction factor for the compressive strength of part j of concrete
k
c,θ,j
giving the strength at elevated temperature f
c,θ
reduction factor for the compressive strength of concrete giving the
k
c,θ,max
strength corresponding to the maximum temperature θ
c,max
oSIST prEN 1994-1-2:2024
prEN 1994-1-2:2024 (E)
reduction factor for the elastic modulus of structural steel or
reinforcing bars giving the slope of the linear elastic range at elevated
kE,θ
temperature E
a,θ
reduction factor for the elastic modulus of part i of structural steel or
reinforcing bars giving the slope of the linear elastic range at elevated
k
E,θ,j
temperature E
a,θ
reduction factor for the yield strength of structural steel or
k reinforcing bars giving the maximum stress level at elevated
y,θ
temperature f
a,θ
reduction factor for the yield strength of structural steel or
k reinforcing bars for the elemental area A giving the maximum stress
y,θ,i i
level at elevated temperature f or f
a,θ s,θ
reduction factor for the yield strength of structural steel or
reinforcing bars giving the proportional limit at elevated
k
p,θ
temperature f or f
ap,θ sp,θ
k , k reduction factor for the yield strength of a reinforcing bar
r s
k correction factor for the shadow effect
sh
reduction factor for the yield strength of structural steel giving the
k
u,θ
strain hardening stress level at elevated temperature q
temperature-dependent reduction factor for a strength or stiffness
k
θ
property
l length at 20 °C of the member
l , l , l specific dimensions of the re-entrant or trapezoidal steel sheeting
1 2 3
l width of support of the concrete slab
a
l buckling length of the column in the fire situation
fi
l length of weld
w
design transverse bending moment
...
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