prEN ISO 17660-1

Welding and allied processes - Welding of reinforcing steel - Part 1: Load-bearing welded joints (ISO/DIS 17660-1:2026)

ISO 17660-1:2006 is applicable to the welding of weldable reinforcing steel and stainless reinforcing steel of load-bearing joints, in workshops or on site. It specifies requirements for materials, design and execution of welded joints, welding personnel, quality requirements, examination and testing.
ISO 17660-1:2006 also covers welded joints between reinforcing steel bars and other steel components, such as connection devices and insert anchors, including prefabricated assemblies. Non load-bearing joints are covered by ISO 17660-2.
ISO 17660-1:2006 is not applicable to factory production of welding fabric and lattice girders using multiple spot welding machines or multiple projection welding machines.
The requirements of ISO 17660-1:2006 are only applicable to static loaded structures.

Schweißen und verwandte Verfahren - Schweißen von Betonstahl - Teil 1: Tragende Schweißverbindungen (ISO/DIS 17660‑1:2026)

Soudage et techniques connexes - Soudage des aciers pour armatures - Partie 1: Assemblages transmettant des efforts (ISO/DIS 17660-1:2026)

L'ISO 17660-1:2006 est applicable au soudage, en atelier et sur chantier, des aciers soudables pour armatures et des aciers inoxydables pour armatures des assemblages transmettant des efforts. Elle spécifie les exigences relatives aux matériaux, à la conception et à l'exécution des assemblages soudés, au personnel de soudage, aux exigences de qualité, aux examens, contrôles et essais.
L'ISO 17660-1:2006 couvre également les assemblages soudés entre les barres en acier pour armatures et d'autres éléments en acier, tels que les raccords et les ancrages encastrés, y compris les assemblages préfabriqués. Les assemblages non transmettants sont couverts par l'ISO 17660-2.
L'ISO 17660-1:2006 n'est pas applicable à la production en usine pour souder les armatures en treillis soudés et les poutres en treillis sur machines multipoints ou sur machines de soudage par bossages multiples.
Les exigences de l'ISO 17660-1:2006 ne sont applicables qu'aux structures soumises à des charges statiques.

Varjenje in sorodni postopki - Varjenje betonskega jekla - 1. del: Obremenjeni zvarni spoji (ISO/DIS 17660-1:2026)

ISO 17660-1:2006 se uporablja za varjenje varilne armature iz jekla in nerjaveče armature iz jekla za nosilne spoje, bodisi v delavnicah ali na gradbišču. Določa zahteve za materiale, načrtovanje in izvedbo varjenih spojev, varilno osebje, zahteve glede kakovosti, pregledovanje in preskušanje.
ISO 17660-1:2006 zajema tudi varjene spoje med armaturnimi jeklenimi palicami in drugimi jeklenimi komponentami, kot so povezovalne naprave in vgradni sidri, vključno s predizdelanimi sklopi. Spoji, ki niso nosilni, so zajeti v ISO 17660-2.
ISO 17660-1:2006 se ne uporablja za tovarniško proizvodnjo varilnih mrež in rešetkastih nosilcev z uporabo večtočkovnih varilnih strojev ali večprojekcijskih varilnih strojev.
Zahteve ISO 17660-1:2006 so uporabne le za statično obremenjene konstrukcije.

General Information

• Status: Not Published
• Publication Date: 29-Nov-2027
• ICS: 25.160.10 - Welding processes
• ICS: 25.160.40 - Welded joints and welds
• Technical Committee: CEN/TC 121 - Welding
• Drafting Committee: CEN/TC 121/WG 16 - Welding of reinfocing steels
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 07-May-2026
• Completion Date: 07-May-2026
• Ref Project: oSIST prEN ISO 17660-1:2026 - Welding and allied processes - Welding of reinforcing steel - Part 1: Load-bearing welded joints (ISO/DIS 17660-1:2026)

Relations

• Revises: EN ISO 17660-1:2006 - Welding - Welding of reinforcing steel - Part 1: Load-bearing welded joints (ISO 17660-1:2006)
• Effective Date: 06-May-2024

Overview

prEN ISO 17660-1:2026 – Welding and Allied Processes – Welding of Reinforcing Steel – Part 1: Load-bearing Welded Joints – is an international draft standard developed by CEN and ISO under the reference ISO/DIS 17660-1:2026. This standard establishes requirements for the welding of weldable reinforcing steel and stainless reinforcing steel in load-bearing joints, both in workshop settings and on construction sites.

The document provides a framework for the selection of materials, joint design, welding execution, qualification of welding personnel, quality requirements, as well as the examination and testing of welded joints. The scope extends to welded connections between reinforcing steel bars and additional steel components, such as connection devices, insert anchors, and prefabricated assemblies. It specifically covers structures subjected to static loads, distinguishing load-bearing joints (covered by this part) from non-load-bearing ones (addressed by ISO 17660-2).

Key Topics

• Applicability: Covers welding of reinforcing steel for load-bearing applications in static-loaded concrete structures. Not applicable to the manufacture of welded fabrics or lattice girders by multiple spot/projection welding machines.
• Types of Welded Joints:
  • Butt joints
  • Lap joints
  • Strap joints
  • Cross joints
  • Joints between reinforcing steel bars and other steel components
• Requirements for Materials: Specifies properties and suitability criteria for reinforcing steel types and welding consumables.
• Design and Execution: Includes recommendations on weld geometry, bar diameters, and preparation practices that ensure joint integrity and design performance.
• Welding Personnel: Outlines required qualifications for welders, welding operators, and coordinators, ensuring personnel competencies meet industry standards.
• Quality Requirements: Sets out requirements for quality control during fabrication, including welding procedure specification, validation, and ongoing production testing.
• Testing and Inspection: Describes mechanical tests (tensile, shear, bend testing), visual inspections, and acceptance criteria for welded joints.

Applications

prEN ISO 17660-1 is critical for:

• Civil engineering and construction: Ensuring the structural integrity of reinforced concrete components in buildings, bridges, tunnels, and infrastructure.
• Prefabricated assemblies: Defining standards for welded joints in factory-built elements, such as cages, beams, columns, and connection devices.
• Project quality management: Supporting engineers, contractors, and quality assurance teams in achieving compliance with international welding standards in load-bearing applications.
• Welding coordination and training: Offering a reference for certifying welding personnel and developing appropriate procedure specifications for reinforcing steel welding.

By following this standard, stakeholders like structural designers, contractors, fabricators, and welding inspectors can be confident that load-bearing welded joints will meet required safety and performance levels.

Related Standards

Several international standards referenced by prEN ISO 17660-1 provide additional technical detail and requirements, including:

• ISO 3834-3: Quality requirements for fusion welding of metallic materials – Standard quality requirements.
• ISO 4063: Welding, brazing, soldering, and cutting – Nomenclature of processes and reference numbers.
• ISO 5817: Fusion-welded joints in steel – Quality levels for imperfections.
• ISO 9606-1: Qualification testing of welders – Fusion welding of steels.
• ISO 14731: Welding coordination – Tasks and responsibilities.
• ISO 15609, 15614 series: Specification, qualification, and testing of welding procedures for metallic materials.
• ISO 17637 & ISO 17639: Non-destructive and destructive testing of welds, including visual, macroscopic, and microscopic inspections.
• ISO 15630: Test methods for steel reinforcing and prestressing materials.

Referencing these standards ensures a comprehensive approach to welding quality, personnel qualification, and structural safety in reinforced concrete construction.

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Keywords: prEN ISO 17660-1, welding of reinforcing steel, load-bearing welded joints, ISO/DIS 17660-1:2026, CEN, workshop welding, site welding, reinforcing bar welding, quality requirements, welding procedure, load-bearing joints, construction standards, structural welding, welded joint testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2026
Varjenje in sorodni postopki - Varjenje betonskega jekla - 1. del: Obremenjeni
zvarni spoji (ISO/DIS 17660-1:2026)
Welding and allied processes - Welding of reinforcing steel - Part 1: Load-bearing
welded joints (ISO/DIS 17660-1:2026)
Schweißen und verwandte Verfahren - Schweißen von Betonstahl - Teil 1: Tragende
Schweißverbindungen (ISO/DIS 17660-1:2026)
Soudage et techniques connexes - Soudage des aciers pour armatures - Partie 1:
Assemblages transmettant des efforts (ISO/DIS 17660-1:2026)
Ta slovenski standard je istoveten z: prEN ISO 17660-1
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 17660-1
ISO/TC 44/SC 10
Welding and allied processes –
Secretariat: DIN
Welding of reinforcing steel —
Voting begins on:
Part 1: 2026-05-04
Load-bearing welded joints
Voting terminates on:
2026-07-27
ICS: 25.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
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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.
Reference number
ISO/DIS 17660-1:2026(en)
DRAFT
ISO/DIS 17660-1:2026(en)
International
Standard
ISO/DIS 17660-1
ISO/TC 44/SC 10
Welding and allied processes –
Secretariat: DIN
Welding of reinforcing steel —
Voting begins on:
Part 1:
Load-bearing welded joints
Voting terminates on:
ICS: 25.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
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BE CONSIDERED IN THE LIGHT OF THEIR
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Published in Switzerland Reference number
ISO/DIS 17660-1:2026(en)
ii
ISO/DIS 17660-1:2026(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms. 3
5 Welding processes . 3
6 Preparations and specifications for welded joints . 4
6.1 General .4
6.2 Butt joints .5
6.2.1 Butt joints welded by welding process 111, 114, 135, 136, 138 or 141 .5
6.2.2 Butt joints welded by welding process 24, 25, 42 or 47 .5
6.3 Lap joints .6
6.4 Strap joints .6
6.5 Cross joints .7
6.5.1 General .7
6.5.2 Cross joints by welding process 111, 114, 135, 136, 138 or 141 .7
6.5.3 Cross joints by welding process 21 or 23 .8
6.6 Joints between reinforcing steel bars and other steel components.9
6.6.1 General .9
6.6.2 Types of joint .9
7 Materials .12
7.1 Parent materials . 12
7.1.1 Reinforcing steels . 13
7.1.2 Other types of steels . 13
7.1.3 Properties of joined steels . 13
7.2 Welding consumables . 13
8 Quality requirements . 14
9 Welding personnel . 14
9.1 Welding coordination .14
9.2 Welder and operator qualifications .14
9.2.1 Welders .14
9.2.2 Welding operators and resistance weld setters .16
9.3 Validity of qualification test certificate of welder and welding operator .16
10 Welding procedure specification (WPS) .16
11 Welding procedure qualification . 17
11.1 General .17
11.2 Test specimens.17
11.3 Mechanical testing .17
11.4 Acceptance criteria .17
11.5 Range of qualification .17
11.5.1 Material.17
11.5.2 Type of welded joint.18
11.5.3 Diameter of reinforcing steel bar and material thickness .18
11.5.4 Other essential variables . 20
11.6 Validity of welding procedure qualification . 20
12 Production weld test .20
12.1 General . 20
12.2 Continuous production weld test in workshops .21
12.3 On-site production weld test . .21
13 Execution and inspection of production welding of reinforcing steel .21

iii
ISO/DIS 17660-1:2026(en)
13.1 General .21
13.2 Welding of bent reinforcing steel bars . 22
13.3 Welds made by welding process 47 . . 23
14 Visual and mechanical testing of specimens .23
14.1 General . 23
14.2 Tensile test . 23
14.2.1 Test specimen . 23
14.2.2 Test procedure. 23
14.2.3 Evaluation of test results . 23
14.2.4 Report of test results .24
14.3 Shear test . 25
14.3.1 Test specimen . 25
14.3.2 Test procedure. 25
14.3.3 Evaluation of test results . 25
14.3.4 Report of test results . 25
14.4 Bend test . 26
14.4.1 Test specimen . 26
14.4.2 Test procedure. 26
14.4.3 Evaluation of test results . 26
Annex A (informative) Welding procedure specification (WPS) .27
Annex B (informative) Technical knowledge of welding coordinatorfor welding reinforcing
steel bars .31
Annex C (informative) Test specimens .32
Annex D (informative) Assessment of the manufacturer performing welding .36
Annex E (informative) Evaluation of testing of welded joints .37
Annex F (informative) Classification of shear strength of load-bearing cross joints .40
Annex G (informative) Examples of diameter combinations for welding cross joints . 41
Annex H (informative) Welder qualification test certificate .42
Annex I (informative) Welding operator qualification test certificate .44
Annex J (informative) Production book welding reinforcing steel .46
Bibliography .49

iv
ISO/DIS 17660-1:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes, Subcommittee
SC 10, Quality management in the field of welding.
ISO 17660 consists of the following parts, under the general title Welding — Welding of reinforcing steel:
— Part 1: Load-bearing welded joints
— Part 2: Non-load-bearing welded joints
This second edition cancels and replaces the first edition (ISO 17660-2:2006). The main changes in this
edition are as follows:
— Figures 2, 3, 4, 9 ,10 and tables from 3 to 10 have been technically revised
— Tables from 3 to 10 have been added
— 9.2.1 Expiring conditions of basic welder qualification have been added
— 12.2 Production weld test requalification interval for high performance have been provided with:
Example for dealing with multiple procedures
Risk analysis by the manufacturer
— Annex H “Welder certificate”, Annex I “Operator certificate” and Annex J “Production book” have been
added
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
DRAFT International Standard ISO/DIS 17660-1:2026(en)
Welding and allied processes – Welding of reinforcing steel —
Part 1:
Load-bearing welded joints
1 Scope
This part of ISO 17660 is applicable to the welding of weldable reinforcing steel and stainless reinforcing
steel of load-bearing joints, in workshops or on site. It specifies requirements for materials, design and
execution of welded joints, welding personnel, quality requirements, mechanical testing.
This document also covers welded joints between reinforcing steel bars and other steel components, such as
connection devices and insertion anchors, including prefabricated assemblies. Non-load-bearing joints are
covered by ISO 17660-2.
This document is not applicable to factory production of welding fabric and lattice girders using multiple
spot-welding machines or multiple projection welding machines.
This document is applicable to static loaded structures. For fatigue-loaded structures, an appropriate
reduction in fatigue strength should be taken into account.
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.
ISO 3834-3, Quality requirements for fusion welding of metallic materials — Part 3: Standard quality
requirements
ISO 4063, Welding, brazing, soldering and cutting — Nomenclature of processes and reference numbers
ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) —
Quality levels for imperfections
ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels
ISO 14554-2, Quality requirements for welding — Resistance welding of metallic materials — Part 2: Elementary
quality requirements
ISO 14731, Welding coordination — Tasks and responsibilities
ISO 14732, Welding personnel — Qualification testing of welding operators and weld setters for mechanized and
automatic welding of metallic materials
ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 1: Arc welding
ISO 15609-2, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 2: Gas welding
ISO 15609-5, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 5: Resistance welding

ISO/DIS 17660-1:2026(en)
ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
ISO 15614-12, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 12: Spot, seam and projection welding
ISO 15614-13, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 13: Upset (resistance butt) and flash welding
ISO 15620, Welding — Friction welding of metallic materials
ISO 15630-1, Steel for the reinforcement and prestressing of concrete — Test methods — Part 1: Reinforcing
bars, rods and wire
ISO 15630-2, Steel for the reinforcement and prestressing of concrete — Test methods — Part 2: Welded fabric
and lattice girders
ISO 16020, Steel for the reinforcement and prestressing of concrete — Vocabulary
ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints
ISO 17639, Destructive tests on welds in metallic materials — Macroscopic and microscopic examination of
welds
EN 10164, Steel products with improved deformation properties perpendicular to the surface of the product —
Technical delivery conditions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16020 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
load-bearing welded joint
welded joint used for transmission of specified loads between reinforcing steel bars or between reinforcing
steel bars and other steel products
3.2
non-load-bearing welded joint
welded joint whose strength is not taken into account in the design of the reinforced concrete structure
Note 1 to entry: The purpose of a non-load-bearing welded joint is usually only to keep the reinforcing components in
their correct places during fabrication, transport and concreting. The weld is often called tack weld.
3.3
shear factor
S
f
relation between the shear force of a cross joint and the nominal yield strength R , multiplied by the nominal
e
cross section area A , of the loaded bar
s
3.4
welder
person who holds and manipulates the electrode holder, welding torch or blowpipe by hand
3.5
manufacturer
person or organization responsible for the welding production

ISO/DIS 17660-1:2026(en)
3.6
examiner
person appointed to verify compliance with the applicable standard
Note 1 to entry: In certain cases, an external independent examiner can be required
3.7
examining body
organization appointed to verify compliance with the applicable standard
Note 1 to entry: In certain cases, an external independent examining body can be required
4 Symbols and abbreviated terms
a throat thickness
A percentage total extension at maximum force
gt
b excess of the bar
d, d , d nominal diameter of the welded bar
1 2
d maximum nominal diameter of the welded bar
max
d minimum nominal diameter of the welded bar
min
e distance between the bars
F force to be anchored by transverse bar
F maximum tensile force
max
F shear force
s
l length of the weld (cross joint)
l overall lap length
o
L minimum length of the test specimen
min
r radius of bent reinforcing steel bar
R specified characteristic yield strength of the reinforcing steel
e
R nominal tensile strength of the reinforcing steel
m
5 Welding processes
The common welding processes are listed in Table 1 in accordance with ISO 4063.

ISO/DIS 17660-1:2026(en)
Table 1 — List of welding processes and reference numbers in accordance with ISO 4063
Welding process Term US synonym
Manual metal arc welding
111 Shielded metal arc welding
(Metal arc welding with covered electrode)
114 Self-shielded tubular cored arc welding
Gas metal arc welding using active gas
135 MAG welding with solid wire electrode
with solid-wire electrode
Gas metal arc welding using active gas
136 MAG welding with flux cored electrode
and flux-cored electrode
Gas metal arc welding using active gas
138 MAG welding with metal cored electrode
and metal cored electrode
Gas tungsten arc welding using inert gas
141 TIG welding with solid filler material (wire/rod)
and solid filler material (wire/rod)
21 Resistance spot welding Spot welding
23 Projection welding
24 Flash welding
25 Resistance butt welding Upset welding
42 Friction welding
47 Oxyfuel gas pressure welding Pressure gas welding
The principles of this document may be applied to other welding processes.
NOTE The welding process 47 with high heat input may be critical for cold worked and heat-treated reinforcing
steels.
6 Preparations and specifications for welded joints
6.1 General
A summary of recommended ranges of bar diameters for load-bearing welded joints, depending on the
welding process, is given in Table 2.
The welds shall not affect the full load-carrying capacity and ductility of the bars. The measures to achieve
this should be specified in the design.
Table 2 — Recommended ranges of bar diameters for load-bearing welded joints
Range of bar diameters for
load-bearing welded joints
Type of welded joint Welding process
mm
16 to 50, for without bucking
111, 114, 135, 136, 138, 141
12 to 50, for with permanent bucking
butt joint 24 5 to 50
25 5 to 25
42, 47 16 to 50
lap joint 111, 114, 135, 136, 138, 141 6 to 40
strap joint 111, 114, 135, 136, 138, 141 16 to 50
111, 114, 135, 136, 138, 141
joint to other steel component 8 to 50
111, 114, 135, 136, 138, 141 10 to 50
a
cross joint
21, 23 5 to 32
a
d / d should be ≥ 0,4.
min max
ISO/DIS 17660-1:2026(en)
The joints specified in 6.2, 6.3, 6.4 and 6.6 except joints on bent bar specified in 6.6.2.1 are designed to give
full load-bearing capacity of the bar. Exceptions are possible for butt welds and joints between reinforcing
steel bars and other steel components, but the specifications shall be specified.
For cross joints, specified in 6.5, the shear strength shall be specified in the design (see also Annex F).
For joints specified in 6.6.2.1 with bent bar under an angle the load is ruled by transverse shearing off the
weld. The shear strength should be designed as necessary.
The joints specified in 6.2 to 6.6 are examples of good practice. Other joint configurations and bar diameters
may be used if they can be shown to meet the requirements of Clause 11.
NOTE Excessive heat input may affect strength and ductility of the bar depending on steel grade process route,
joint configuration and bar diameter.
6.2 Butt joints
6.2.1 Butt joints welded by welding process 111, 114, 135, 136, 138 or 141
Examples of butt-joint preparation are given in Figure 1 a) to d). Other joint preparations or types of
permanent backing may also be used.
The prepared joint shall be bevelled. The joint preparation should be carried out by grinding or flame cutting.
a) Double-V butt weld b) Single-V butt weld
c) Double-bevel butt weld d) Single-V butt weld with backing
Key
x root gap
y depth of root face
NOTE x or y depends on the welding process.
Figure 1 — Examples for the preparation of butt joints
6.2.2 Butt joints welded by welding process 24, 25, 42 or 47
For welding process 24 or 25, the misalignment of the bars shall not exceed 1 mm for nominal bar diameters
less than or equal to 10 mm, and 10 % of the nominal bar diameter for the other values.

ISO/DIS 17660-1:2026(en)
For welding process 24 or 25, only bars with the same diameter shall be welded together.
For welding process 42, the maximum misalignment of the bars shall be specified.
For welding process 47, the bars with different diameters shall not be welded in case that the difference of
their nominal diameters exceeds 7 mm.
For welding process 47, the misalignment of the bars shall not exceed 20 % of the smaller nominal bar
diameter of the two welded bars.
NOTE Excessive heat input may loss of strength and ductility.
An example of the joint preparation for these welding processes is given in Figure 2.
Key
X root gap = 0 mm
Figure 2 — Example for the preparation of butt joints
6.3 Lap joints
Lap joints using intermittent single-flare V-groove welds (asymmetric force flow) shall be welded in
accordance with Figure 3.
Key
1 weld
a throat thickness
d nominal diameter of the smaller of the two welded bars
l overall lap length
o
w weld width
NOTE 1 A conservative estimate of the effective throat thickness can be taken as a ≈ 0,5 w.
NOTE 2 Welding is also possible on both sides with minimum weld length of 2,5 d.
Figure 3 — Lap joint
6.4 Strap joints
Load-bearing strap joints with single-flare V-groove welds shall be welded in accordance with Figure 4.

ISO/DIS 17660-1:2026(en)
Where the straps and the bars have the same mechanical properties, the combined cross-sectional area of
the two straps shall be equal to or greater than the cross-sectional area of the bars to be joined. Where the
straps and the bars do not have the same mechanical properties, the cross-sectional area of the straps shall
be adapted on the basis of the ratio of their individual nominal yield stresses.
Key
1 weld
a throat thickness
d nominal diameter of the smaller of the welded bars with d and the strap bars with d
b s
w weld width
NOTE 1 A conservative estimate of the effective throat thickness can be taken as a ≈ 0,5 w.
NOTE 2 Welding is also possible on both sides with minimum weld length of 2,5 d.
Figure 4 — Strap joint
6.5 Cross joints
6.5.1 General
Unless otherwise specified, cross joints are intended to function in only one direction and are consequently
tested in longitudinal bar direction with the transverse bar supported.
The required shear factor, S , of the joint shall be specified on the drawings and shall be verified by testing in
f
accordance with Clause 14.3. For shear factor classification see Annex F.
6.5.2 Cross joints by welding process 111, 114, 135, 136, 138 or 141
Cross joints shall be welded in accordance with Figure 5. The joint shall be welded, whenever possible,
as double-sided weld (see Figure 5a)). In this case, welds at two sides are preferable in equal welds with
adequate cooling between those two welds.
The minimum bar diameter, d = 10 mm is recommended and the relation, d /d shall be ≥ 0,4
min min max
(recommended ≥ 0,6).
If only one single-sided weld is used, the shear strength of the welded joint shall be verified with the force
applied as shown in Figure 5 b).
Whether welding on double sides or on single side, the following conditions shall be fulfilled to avoid cracks
in the weld:
a) a minimum throat thickness a ≥ 0,3 d ;
min
b) a minimum length of the weld l ≥ 0,5 d .
min
ISO/DIS 17660-1:2026(en)
If more than one transverse bar is used on the same side of the longitudinal bar, the spacing of the transverse
bars shall be at least three times the nominal diameter of the transverse bar.
a) Double-sided weld
b) Single-sided weld
Key
1 longitudinal bar
2 transverse bar
a throat thickness
d nominal diameter of the welded bar
F force to be anchored by transverse bar
Figure 5 — Cross joint welded by welding process 111, 114, 135, 136, 138 or 141
6.5.3 Cross joints by welding process 21 or 23
Cross joints with welding process 21 or 23 shall be welded in accordance with Figure 6.
The relation, d /d shall be ≥ 0,4 (recommended ≥ 0,6).
min max
ISO/DIS 17660-1:2026(en)
Figure 6 — Cross joint welded by welding process 21 or 23
6.6 Joints between reinforcing steel bars and other steel components
6.6.1 General
The material thicknesses of the steel components given in Figures 7 to 10 are prescribed on the basis of
welding criteria. Greater material thicknesses can be required as a result of detailed structural analysis.
If the weld length or material thickness of the steel components vary from the values prescribed in Figures 7,
8, 9 and 10, then the alternative dimensions shall be proven by data provided from actual tests. The details
of such tests shall be specified and documented.
The choice of material, calculation and design of the steel component shall be made in accordance with
relevant design specifications.
6.6.2 Types of joint
6.6.2.1 Flare-bevel-groove weld joints
Load-bearing flare-bevel-groove welds are shown in Figures 7 and 8. For the thickness of the steel
components, the weld length and the weld spacing, the dimensions of Figures 7 and 8 shall be observed.
For welding double-flare-bevel groove welds on bent reinforcing steel bars in accordance with Figure 8, the
requirements of 13.2 also apply.
During assembly, sufficient access for welding shall be maintained.
0,4 d ≤ t, but t = 4 mm
min
a) Single-flare-bevel groove joint

ISO/DIS 17660-1:2026(en)
0,4 d ≤ t, but t = 4 mm
min
b) Double-flare-bevel groove joint
Key
1 weld
d nominal diameter of the welded bars
e distance between the bars
t thickness of the web of a section or of a plate to be welded
t minimum thickness of the web of a section or a plate to be welded
min
Figure 7 — Flare-bevel groove joint on straight reinforcing steel bars
0,4 d ≤ t, but t = 4 mm
min
Key
1 weld
d nominal diameter of the welded bars
t thickness of the web of a section or of a plate to be welded
Figure 8 — Double-flare-bevel groove joint on bent reinforcing steel bar
The weld configuration of flare-bevel groove welds shall be as shown in Figure 9.

ISO/DIS 17660-1:2026(en)
a ~ 0,3 * d, Minimum 3 mm
Key
a throat thickness
d nominal diameter of the welded bar
w weld width
NOTE a ≈ 0,7 w
Figure 9 — Weld configuration of flare-bevel groove weld
6.6.2.2 Transverse end-plate joints
Transverse end-plate joints should be welded in accordance with Figure 10.
Where several reinforcing steel bars are welded to a plate or section, the spacing between bars shall be at
least 3 d.
NOTE This type of joint can be used for the purposes of end anchorage.
a = 0,4 d
b ≥ d
0,4 d ≤ t, but t = 4 mm
min
a) Set-through bar
ISO/DIS 17660-1:2026(en)
α ≥ 45°
s = 0,4 d
t ≥ d
b) Set-in bar
a = 0,4 d
0,4 d ≤ t, but t = 4 mm
min
c) Set-on bar
Key
a throat thickness
b excess of the bar
d nominal diameter of the welded bar
s penetration depth
t plate thickness
t minimum thickness of the web of a section or of a plate to be welded
min
α included angle
Figure 10 — Transverse end-plate joint
Transverse end plate joints in accordance with Figure 10c cover transverse end plate joints in accordance
with Figure 10a, but not vice-versa.
For joints made by fillet welds with set-on bar, as shown in Figure 10 c), the end of the reinforcing steel bar
shall be cut square to the bar axis. There should be no gap between the squared end of the reinforcing steel
bar and the steel component. If a root gap cannot be avoided completely, the intended throat thickness shall
be increased by the width of the gap. The root gap shall not exceed 3mm. Laminations and lamellar tearing
in the steel plate shall be avoided by the choice of a suitable parent material. The steel plate shall be tested,
e.g., in accordance with EN 10164.
7 Materials
7.1 Parent materials
This standard includes the following parent materials.

ISO/DIS 17660-1:2026(en)
7.1.1 Reinforcing steels
Weldable reinforcing steel and stainless reinforcing steel, in accordance with the relevant standards or
technical specification, may be used. For refurbishment and extensions of buildings, the weldability of the
existing reinforcing steel shall be verified.
The weldability of stainless reinforcing steel shall be considered by reference to material specifications and
welding procedures.
7.1.2 Other types of steels
The reinforcing steels may also be welded to other types of steels (e.g., weldable structural steels or stainless
steels). The welding to those steels shall be in accordance with the relevant standard or the technical
specification. The weldability to the steel shall be verified in case that there is not any specification.
7.1.3 Properties of joined steels
The carbon equivalent value (CEV), the manufacturing route and the delivery conditions shall be determined
before welding. If those conditions are not already included in the steel designation or steel grade, see 11.5.1,
the production conditions shall be indicated in the delivery information by the manufacturer.
NOTE 1 For more information about metallurgical weldability see ISO/TR 581.
For reinforcing steels, the inspection certificate does not need to be provided if the manufacturer of the
reinforcing steel is certified to the relevant product standard for the market.
For unalloyed reinforcement and structural steels, the CEV shall be in accordance with the product standard,
and CEV is calculated with Formula (1):
Mn CrMo VNiC u
CEVC   (1)
65 15
Where the symbols of the chemical elements indicate their content in % by mass.
This requirement for the CEV does not apply if:
a) the weldability is proven by a welding procedure test with a maximum CEV allowed in accordance with
the relevant product standard; or
b) it can be proven that the steel delivered has an equal or lower CEV than the steel used in the welding
procedure test.
The assessment of weldability based on the CEV explained above is not applicable to stainless steels. The
suitability for welding is assessed here on the basis of other consi
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