EN 1994-1-1:2026/prA1

• Abstract:

  1.1 Scope of EN 1994-1-1; (1) EN 1994-1-1 gives general rules for the design of steel and concrete composite structures and supplementary provisions specific for buildings.; NOTE Specific rules for bridges are given in EN 1994-2.; 1.2 Assumptions; (1) The assumptions of EN 1990-1 apply to EN 1994-1-1.; (2) In addition to the general assumptions of EN 1990-1, the assumptions given in EN 1992-1-1, EN 1992-1-2, and EN 1993-1-1 apply to this document.; (3) EN 1994-1-1 is intended to be used in conjunction with EN 1990-1, EN 1991 (all parts), EN 1992-1-1, EN 1993 (all parts), EN 1997 (all parts), EN 1998 (all parts when steel and concrete composite structures are built in seismic regions), EN 1090-1, EN 1090-2, EN 1090-4, EN 13670 and ENs for construction products relevant to steel and concrete composite structures.

• Status: Not Published
• Publication Date: 23-Nov-2027
• ICS: 91.080.13 - Steel structures
• Technical Committee: CEN/TC 250 - Structural Eurocodes
• Drafting Committee: CEN/TC 250/SC 4/WG 4 - Evolution of EN 1994-1-1, EN 1994-1-2 and EN 1994-2
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 17-Sep-2026
• Due Date: 30-Oct-2026
• Completion Date: 17-Sep-2026
• Ref Project: SIST EN 1994-1-1:2026/oprA1:2026 - Eurocode 4 - Design of composite steel and concrete structures - Part 1-1: General rules and rules for buildings

• Amends: EN 1994-1-1:2026 - Eurocode 4 - Design of composite steel and concrete structures - Part 1-1: General rules and rules for buildings
• Effective Date: 24-Jun-2026

EN 1994-1-1:2026/prA1 is a CEN draft amendment to Eurocode 4 for the design of composite steel and concrete structures. It updates the general rules and the rules for buildings, so it is aimed at engineers and other professionals who design, check, test or execute composite beams, slabs, columns and connectors in buildings.

What does EN 1994-1-1:2026/prA1 specify?

EN 1994-1-1:2026/prA1 amends the base Eurocode 4 part that gives general rules for composite steel and concrete structures and supplementary provisions for buildings. Bridge-specific rules are handled in EN 1994-2.

The draft amendment is organized as a set of changes to Clause 0, Clause 3, Clause 5, Clause 7, Clause 8, Clause 9 and Clause 10, plus Annexes B, D, E, F, H, I and J. It also adds a new informative Annex K and updates the bibliography.

Annex	What it covers
B	Standard tests
D	Composite beams with web-openings
E	Composite beams with web-openings and a stiff slab
F	Headed studs that cause splitting forces in the direction of slab thickness
H	Design tension resistance of headed studs
I	Additional rules for shallow floor beams
J	Other flooring types using precast concrete slabs in buildings
K	Guidance for refined crack control from EN 1992-1-1 for composite structures

What are the key requirements of EN 1994-1-1:2026/prA1?

EN 1994-1-1:2026/prA1 mainly tightens and clarifies how composite structures are designed, checked and documented. The most visible changes are in terminology, shear connection, crack control, composite slabs and special detailing cases.

• Clause 3 revises symbols and definitions, including the definition of maximum resistance (R_m) and the symbols used in Annex K. In practice, calculation sheets and design reports need to follow the updated notation.
• Clause 5 updates material references and adds guidance for recycled aggregate concrete through EN 206, EN 1992-1-1 and the related National Annexes. This matters when the concrete mix or source affects design assumptions.
• Clause 7 updates the note on shear lag of the steel part and points designers to EN 1993-1-5:2024. That means the steel member check should be coordinated with the steel Eurocode rules.
• Clause 8 revises ultimate limit state checks, including the (\beta) factor, partial shear connection, nonlinear analysis, and buckling rules for composite columns. In practice, these changes affect resistance and stability verification for beams and columns.
• Clause 9 strengthens serviceability rules for shear connection and connector stiffness. It links connector resistance to Annex B, CEN/TS 1994-1-102 or equally reliable sources, and adds the crack-control guidance of Annex K.
• Clause 10 updates composite slabs with profiled steel sheeting, including transverse moment checks and construction-stage shear forces. Designers need to verify slab behaviour both during construction and in the final condition.
• Annexes D, E, F, H, I and J revise special cases such as web openings, stiff slabs, headed studs, shallow floor beams and precast-slab flooring. These annexes are the parts to consult when a project uses one of those detailing options.

What terms does EN 1994-1-1:2026/prA1 define?

EN 1994-1-1:2026/prA1 uses several key terms and symbols that matter in calculations.

• Composite steel and concrete structures - structures where steel and concrete act together through designed connection.
• Shear connection - the connectors and detailing that transfer longitudinal shear between the steel part and the concrete part.
• Maximum resistance (R_m) - the resistance based on mean material properties.
• Slip capacity (\delta_{uk}) - the slip limit used for partial shear connection checks.
• Calculated characteristic crack width (w_{k,cal}) - the crack-width value used in Annex K for refined crack control.
• Normal weight concrete (NWAC) - the concrete type used in connector stiffness guidance in Annex K.
• Lightweight concrete (LWAC) - the lightweight concrete type used in the same stiffness guidance.

Who uses EN 1994-1-1:2026/prA1?

EN 1994-1-1:2026/prA1 is used by structural engineers, design offices, checking authorities, manufacturers and testing laboratories working on composite buildings. It is also relevant to buyers and quality managers who need to specify or verify composite steel-concrete products, shear connectors, profiled steel sheeting, precast slab systems and execution requirements.

What changed in EN 1994-1-1:2026/prA1 from the previous edition?

EN 1994-1-1:2026/prA1 is a draft amendment to EN 1994-1-1:2026. It revises terminology, materials, structural analysis, ultimate and serviceability limit states, composite slabs, standard tests and several special annexes, and it adds new informative guidance in Annex K. The foreword also notes that some modifications are purely editorial corrections.

Which standards are used with EN 1994-1-1:2026/prA1?

Standard	What it contributes
EN 1990-1	General assumptions
EN 1991 (all parts)	Actions on structures
EN 1992-1-1	Concrete design rules and crack-control basis
EN 1992-1-2	Additional assumptions for fire-related design
EN 1993 (all parts)	Steel design rules
EN 1993-1-5:2024	Shear lag rules for the steel part
EN 1993-1-13:2024	Effective opening length used in web-opening design
EN 1994-2	Bridge-specific Eurocode 4 rules
EN 1997 (all parts)	Geotechnical design
EN 1998 (all parts)	Seismic design where composite structures are used in seismic regions
EN 1090-1, EN 1090-2, EN 1090-4	Execution of steel-related construction products and works
EN 13670	Execution of concrete structures
EN 206	Concrete specification, production and conformity
CEN/TS 1994-1-102:2025	Alternative source of connector resistance information and related guidance

What does the EN 1994-1-1:2026/prA1 document contain?

The document contains amendment instructions, updated figures, revised tables and new formulas for design checks. It covers connector resistance and stiffness, web openings, stiff-slab openings, shallow floor beams, composite slabs with profiled steel sheeting and refined crack-control calculations. In practice, it is used for design, testing, verification and detailing of composite steel and concrete structures.

SLOVENSKI STANDARD
01-november-2026
Evrokod 4 - Projektiranje sovprežnih konstrukcij iz jekla in betona - 1-1. del:
Splošna pravila in pravila za stavbe
Eurocode 4 - Design of composite steel and concrete structures - Part 1-1: General rules
and rules for buildings
Eurocode 4 - Bemessung und Konstruktion von Verbundtragwerken aus Stahl und Beton
- Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau
Eurocode 4 - Calcul des structures mixtes acier-béton - Partie 1-1 : Règles générales et
règles pour les bâtiments
Ta slovenski standard je istoveten z: EN 1994-1-1:2026/prA1
ICS:
91.010.30 Tehnični vidiki Technical aspects
91.080.13 Jeklene konstrukcije Steel structures
91.080.40 Betonske konstrukcije Concrete structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
EN 1994-1-1:2026
NORME EUROPÉENNE
EUROPÄISCHE NORM
prA1
September 2026
ICS
English Version
Eurocode 4 - Design of composite steel and concrete
structures - Part 1-1: General rules and rules for buildings
Eurocode 4 - Calcul des structures mixtes acier-béton - Eurocode 4 - Bemessung und Konstruktion von
Partie 1-1 : Règles générales et règles pour les Verbundtragwerken aus Stahl und Beton - Teil 1-1:
bâtiments Allgemeine Bemessungsregeln und Regeln für den
Hochbau
This draft amendment is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 250.

This draft amendment A1, if approved, will modify the European Standard EN 1994-1-1:2026. 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, 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1994-1-1:2026/prA1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Modification to Clause 0 Introduction . 3
2 Modification to Clause 3, “Terms, definitions and symbols” . 3
3 Modification to Clause 5, “Materials” . 4
4 Modification to Clause 7, "Structural analysis" . 4
5 Modification to Clause 8, "Ultimate limit states" . 5
6 Modification to Clause 9, “Serviceability limit states” . 10
7 Modification to Clause 10, “Composite slabs with profiled steel sheeting for buildings”
................................................................................................................................................................... 10
8 Modification to Annex B, Standard tests . 11
9 Modification to Annex D, Composite beams with web-openings . 11
10 Modification to Annex E, Composite beams with web-openings and a stiff slab . 12
11 Modification to Annex F, “Headed studs that cause splitting forces in the direction of
the slab thickness” . 13
12 Modification to Annex H, “Design tension resistance of headed” . 13
13 Modification to Annex I, Additional rules for shallow floor beams . 13
14 Modification to Annex J, Other flooring types using precast concrete slabs in buildings
................................................................................................................................................................... 14
15 Addition of Annex K Guidance for the application of clause 9.2.3 Refined control of
cracking of EN 1992-1-1 . 14
16 Modifications to the Bibliography . 17

European foreword
This document (EN 1994-1-1:2026/prA1:2026) has been prepared by Technical Committee CEN/TC 250
“Structural Eurocodes”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1994-1-1:2026.
NOTE Some modifications are purely editorial corrections to improve the quality of the document and these
will not be tagged in the consolidated publication, as noted after the modification.
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 recognise 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.
1 Modification to Clause 0 Introduction
0.5 Add “Annex K” to the list of informative annexes in the paragraph: “National choice is allowed in EN
1994-1-1 on the application of the following informative annexes, in alphabetical order.”
2 Modification to Clause 3, “Terms, definitions and symbols”
3.2.1 Replace the definition of R with “Maximum resistance based on mean values of material properties”
m
3.2.1 In definition of V replace “acting on” with “in”.
a,Ed
3.2.1 In definition of V replace “acting on” with “in”.
c,Ed
3.2.1 In definition of V replace “acting on” with “in”.
Ed
3.2.1 In definition of P replace “acting on” with “in”.
s,Ed
3.2.1 In definition of P replace “acting on” with “in”.
ten,Ed
3.2.1 In definition of V replace “acting on” with “in”.
bT,Ed
3.2.1 In definition of V replace “acting on” with “in”.
iT,Ed
3.2.1 In definition of Voa,Ed replace “acting on” with “in”.
3.2.1 In definition of V replace “acting on” with “in”.
oc,Ed
3.2.1 In definition of V replace “acting on” with “in”.
o,Ed
3.2.1 In definition of V replace “acting on” with “in”.
tT,Ed
3.2.2 Add “w maximum deflection at the maximum resistance R ”
u m
3.5.2 Replace “s ” with “s”
3.8.3 In definition of ψ replace “acting on” with “in”.
ec,N
Add the following new clause
“3.11 Additional symbols used in Annex K
3.11.1 Latin lower case letters
a Distance from the outermost fibre in tension to the centre of the nearest reinforcement bar
z
c Cover from the concrete surface in tension to the surface of the closest bar
h Total height of the composite section
k Factor accounting for the increase of crack width due to curvature
1/r
k Factor accounting for the short-term (creep and shrinkage to be excluded) distribution of stresses
fl
between cracks
k Coefficient dependent on the duration and nature of load
t
k Factor to convert the mean crack width into a calculated crack width
w
z Depth of the neutral axis, measured from the most compressed fibre and determined with section
r
properties assuming a cracked concrete flange
3.11.2 Greek lower case letters
ε Strain in the most tensioned fibre concrete fibre determined using uncracked short-term section
properties
ε Strain in the least tensioned fibre concrete fibre determined using uncracked short-term section
properties
εcm Mean concrete strain due to external loads and shrinkage
ε Free shrinkage strain of concrete
cs
ε Mean steel strain due to external loads and shrinkage
sm
ρ Reinforcement ratio of the slab”
3 Modification to Clause 5, “Materials”
5.1(8) Replace “Annex M” with “Annex N”
5.1(8) Add a NOTE below “lightweight aggregate concrete.”:
“NOTE Guidance for the application of Recycled Aggregate Concrete is given in EN 206, EN 1992-1-1 and
the related National Annexes.”
5.4.2.1(1) Delete the word “see” before “Figure 5.1”
5.4.2.1(8) Delete this paragraph
4 Modification to Clause 7, "Structural analysis"
7.4.1.2(2) Replace the NOTE with “NOTE For general provisions related to shear lag of the steel part in
member design, see EN 1993-1-5:2024, Clause 5.”
7.5.3.2(3) Replace figure in Table 7.2, under “3 Stress distribution (compression positive) to fill steel plate
in black” with the following:
5 Modification to Clause 8, "Ultimate limit states"
8.2.1.2(2) Figure 8.3, in key 5 replace
“S355 with z /h ≤ 0,5: β = 1-0,4(z /h – 0,15) ≤ 1,0”
pl pl
with
“S355 with z /h ≤ 0,5: β = 1-0,333(z /h – 0,2) ≤ 1,0”
pl pl
Replace
“S420/S460 with z /h ≤ 0,4: β = 1-0,333(z /h – 0,2) ≤ 1,0”
pl pl
With
“S420/S460 with z /h ≤ 0,4: β = 1-0,4(z /h – 0,15) ≤ 1,0”.
pl pl
8.2.1.2(4) Replace “When the conditions in (2)b) are satisfied, the coefficient β may be taken as 1,0 if:”
With
“When the conditions in (2)b) (except that concerning the effective width of the concrete flange) are
satisfied, the coefficient β may be taken as 1,0 if:”
8.2.1.2(4)b) Replace “the concrete flange is considered to be either solid or with profiled sheeting and a
concrete depth h of at least 70 mm.”
c
With
“the concrete flange is considered to be either solid or with profiled sheeting and a concrete depth h of
c
at least 50 mm.”
8.2.1.3(2) Figure 8.4, replace “N ” with “N ” as follows:
C,t c,f
8.2.1.3(7) Replace figure 8.6 by moving βM horizontal branch to a lower position to improve clarity and
pl,Rd
both dotted lines must end at the value β M , as follows:
pl
8.2.2.4(3) Replace “acting on” with “in”.
8.2.2.5(1) Replace twice “acting on” with “in”.
8.3.2(2) Replace Figure 8.11 as follows:

8.3.3(3) Replace “acting on” with “in”.
8.6.3.3(1) Replace “For partial shear connection, either the calculated maximum slip should not exceed
the capacity given in 5.4.2.1 or degree of shear connection should comply with the limit in (2).”
with
“For partial shear connection, either the maximum slip should not exceed the slip capacity δ given in
uk
5.4.2.1 or the degree of shear connection should comply with the limit in (2).”
8.6.3.3(2) Modify the definition of nf to: ”number of connectors for full shear connection (N /P ) that are
cf Rd
required between the point of zero moment and the point of maximum moment”
8.6.6(1) Replace the whole of the paragraph with:
”Where non-linear theory according to 8.2.1.5 or 8.2.1.6 is used to determine the resistance, the
longitudinal shear force should be determined in accordance with 8.6.4, where the normal force in the
concrete flange may be determined in accordance with 8.2.1.5 or 8.2.1.6. Alternatively, more advanced
methods in accordance with 8.6.2 may be used.”
8.6.8.1 replace Figure 8.16 with the following:
𝐼𝐼𝐼𝐼
8.8.2(8) In the definition of 𝑁𝑁 replace
𝐸𝐸𝐸𝐸
“the design value N is that from global analysis.”
Ed
With
II
“The value of N may be taken as equal to the design value from the global analysis, N .”
Ed
Ed
8.8.2(8) In the definition of R replace
m
“is the mean value of resistance, obtained from non-linear analysis, as defined in (9);”
with
“is the maximum resistance of the column based on mean material properties when subject to non-linear
analysis in accordance with (9), see Figure 8.25;”
8.8.2(8) Add the following definition: “w maximum deflection of member at the maximum
u
resistance R ”.
m
8.8.2(8) In NOTE 1 replace “The mean value R of the resistance” with “The value of R ”
m m
8.8.2(9) Replace figure 8.25 as follows:
“
”
8.8.2(10) Add “and position along the column” to the end of the existing last sentence.
8.8.2(10) Add a new sentence at the end “The maximum value of γ should be used in the verification in
o
(9).”
8.8.3.2(4) Replace twice “acting on” with “in”
8.8.3.5(2) Table 8.7 Replace the text at the bottom of the table with the following:
“The values in the table above apply to composite columns with doubly-symmetric steel sections as
follow:
• Hot-rolled sections with h/b not greater than 2,4 and a flange thickness t not greater than
f
150mm.
• Hot-rolled sections with h/b greater than 2,4 and a flange thickness t not greater than 40mm.
f
• Welded sections with a flange thickness t not greater than 40mm
f
For hot-rolled sections with h/b greater than 2,4 and a flange thickness t greater than 40mm the buckling
f
curve for buckling about the yy axis should be reduced by one class (e.g. from b to c) and the member
imperfection increased to suit (e.g. from L/200 to L/150).
For welded sections with a flange thickness t greater than 40mm the buckling curve for buckling about
f
both axes should be reduced by one class and the member imperfection increased to suit.”
8.8.4.2(9) Replace figure 8.32 as follows: “

“
8.8.3.5(2) Table 8.7 Replace the text at the bottom of the table with the following:
“The values in the table above apply to composite columns with doubly-symmetric steel sections as
follow:
• Hot-rolled sections with h/b not greater than 2,4 and a flange thickness t not greater than
f
150mm.
• Hot-rolled sections with h/b greater than 2,4 and a flange thickness t not greater than 40mm.
f
• Welded sections with a flange thickness t not greater than 40mm
f
For hot-rolled sections with h/b greater than 2,4 and a flange thickness t greater than 40mm the buckling
f
curve for buckling about the yy axis should be reduced by one class (e.g. from b to c) and the member
imperfection increased to suit (e.g. from L/200 to L/150).
...