ISO 22966:2009
(Main)Execution of concrete structures
Execution of concrete structures
ISO 22966:2009 gives common requirements for the execution of concrete structures and applies to both in-situ works and construction using prefabricated concrete elements. ISO 22966:2009 requires that the execution specification state all the specific requirements relevant to the particular structure. ISO 22966:2009 is applicable to temporary as well as permanent concrete structures. Additional or different requirements can be considered and, if required, given in the execution specification when using lightweight aggregate concrete; other materials (e.g. fibres) or constituent materials; or special technologies/innovative designs. ISO 22966:2009 does not apply to the following: concrete members used only as equipment or construction aids for the execution; specification, production and conformity of concrete; production of precast concrete elements made in accordance with product standards; safety and health aspects of execution, or third-party safety requirements; contractual issues or responsibilities for the identified actions.
Exécution des structures en béton
Izvajanje betonskih konstrukcij
Ta mednarodni standard podaja skupne zahteve za izvajanje betonskih konstrukcij in velja za dela in situ ter gradnjo z uporabo montažnih betonskih elementov.
Ta mednarodni standard zahteva, da specifikacija izvajanja navaja vse posebne zahteve,
pomembne za določeno konstrukcijo.
Ta mednarodni standard velja za začasne in stalne betonske konstrukcije.
Preučijo se lahko dodatne ali drugačne zahteve, ki se po potrebi navedejo v specifikaciji izvajanja, kadar se uporabljajo:
⎯ lahki betonski agregati;
⎯ drugi materiali (npr. vlakna) ali sestavni materiali;
⎯ posebne tehnologije/inovativne zasnove.
Ta mednarodni standard ne velja za naslednje:
a) betonske elemente, ki se uporabljajo le kot oprema ali gradbena pomoč pri izvedbi;
b) specifikacijo, proizvodnjo in skladnost betona;
c) proizvodnjo montažnih betonskih elementov, narejenih v skladu s standardi za proizvode;
d) varnostne in zdravstvene vidike izvedbe ali varnostnih zahtev tretje strani;
e) pogodbenih vprašanj ali odgovornosti za opredeljene ukrepe.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2011
Izvajanje betonskih konstrukcij
Execution of concrete structures
Exécution des structures en béton
Ta slovenski standard je istoveten z: ISO 22966:2009
ICS:
91.080.40 Betonske konstrukcije Concrete structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 22966
First edition
2009-11-15
Execution of concrete structures
Exécution des structures en béton
Reference number
©
ISO 2009
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ii © ISO 2009 – All rights reserved
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Execution management .4
4.1 Assumptions.4
4.2 Documentation .5
4.3 Quality management .6
4.4 Action in the event of a non-conformity .8
5 Falsework and formwork .8
5.1 Basic requirements .8
5.2 Materials .9
5.3 Design and installation of falsework .9
5.4 Design and installation of formwork .9
5.5 Special formwork.10
5.6 Inserts in formwork and embedded components .10
5.7 Removal of formwork and falsework.10
6 Reinforcement .11
6.1 General .11
6.2 Materials .11
6.3 Bending, cutting, transport and storage of the reinforcement.12
6.4 Welding.13
6.5 Joints .13
6.6 Assembly and placing of the reinforcement.13
7 Prestressing.13
7.1 General .13
7.2 Materials for prestressing.14
7.3 Transport and storage .15
7.4 Installation of tendons .15
7.5 Tensioning .16
7.6 Protective measures (grouting, greasing) .17
8 Concreting.18
8.1 Specification of concrete.18
8.2 Pre-concreting operations.18
8.3 Delivery, reception and site transport of fresh concrete .19
8.4 Placing and compaction .19
8.5 Curing and protection.20
8.6 Post-concreting operations.22
8.7 Concreting of composite structures .22
8.8 Surface finish.22
9 Execution with precast concrete elements.22
9.1 General .22
9.2 Factory produced precast elements.22
9.3 Site-manufactured precast elements .22
9.4 Handling and storage.23
9.5 Placing and adjustment .23
9.6 Jointing and completion works.24
10 Geometrical tolerances .24
10.1 General.24
10.2 Reference system .25
10.3 Base supports (foundations).25
10.4 Columns and walls .26
10.5 Beams and slabs.27
10.6 Sections .28
10.7 Surfaces and edge straightness .30
10.8 Tolerances for holes and inserts .30
Annex A (informative) Guidance on documentation .31
Annex B (informative) Guidance on quality management .36
Annex C (informative) Guidance on falsework and formwork.38
Annex D (informative) Guidance on reinforcement .40
Annex E (informative) Guidance on prestressing.42
Annex F (informative) Guidance on concreting .45
Annex G (informative) Guidance on geometrical tolerances.51
Annex H (informative) Guidance on national annex .58
Bibliography .59
iv © ISO 2009 – All rights reserved
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 22966 was prepared by Technical Committee ISO/TC 71, Concrete, reinforced concrete and prestressed
concrete, Subcommittee SC 3, Concrete production and execution of concrete structures.
Introduction
This International Standard applies to the execution of concrete structures to achieve the intended levels of
[3]
reliability and serviceability that are given in ISO 2394 and in standards for the design of concrete structures.
This International Standard has three functions:
⎯ to transfer the requirements set during design from the designer to the constructor, i.e. to be a link
between design and execution;
⎯ to give a set of standardized technical requirements for the execution when ordering a concrete structure;
⎯ to serve as a check list for the designer to ensure that he provides the constructor with all relevant
technical information for the execution of the structure; see Annex A.
In order to achieve these objectives, it is necessary that the designer prepare a set of documents and
drawings giving all information required for the execution of the work in accordance with the plans. This set of
documents is in this International Standard referred to as the “execution specification”. This International
Standard leaves a number of items open that can be decided by the execution specification.
It is necessary that the execution specification refer to national provisions in areas where these apply.
It is recognized in this International Standard that areas such as detailed requirements for competence of
personnel and details related to quality management are within the competence of the member states.
A national annex can refer to national standards approved and published by an ISO member body and that
supplement this International Standard; alternatively, the supplementing rules can be given directly in the
national annex.
vi © ISO 2009 – All rights reserved
INTERNATIONAL STANDARD ISO 22966:2009(E)
Execution of concrete structures
1 Scope
This International Standard gives common requirements for the execution of concrete structures and applies
to both in-situ works and construction using prefabricated concrete elements.
This International Standard requires that the execution specification state all the specific requirements
relevant to the particular structure.
This International Standard is applicable to temporary as well as permanent concrete structures.
Additional or different requirements can be considered and, if required, given in the execution specification
when using
⎯ lightweight aggregate concrete;
⎯ other materials (e.g. fibres) or constituent materials;
⎯ special technologies/innovative designs.
This International Standard does not apply to the following:
a) concrete members used only as equipment or construction aids for the execution;
b) specification, production and conformity of concrete;
c) production of precast concrete elements made in accordance with product standards;
d) safety and health aspects of execution, or third-party safety requirements;
e) contractual issues or responsibilities for the identified actions.
2 Normative references
The following referenced documents are indispensable for the application 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 6934 (all parts), Steel for the prestressing of concrete
ISO 6935-1, Steel for the reinforcement of concrete — Part 1: Plain bars
ISO 6935-2, Steel for the reinforcement of concrete — Part 2: Ribbed bars
ISO 15630-1, Steel for the reinforcement and prestressing of concrete — Test methods — Part 1: Reinforcing
bars, wire rod and wire
ISO 17660-1, Welding — Welding of reinforcing steel — Part 1: Load-bearing welded joints
ISO 17660-2, Welding — Welding of reinforcing steel — Part 2: Non-load-bearing welded joints
ISO 22965-1, Concrete — Part 1: Methods of specifying and guidance for the specifier
ISO 22965-2, Concrete — Part 2; Specification of constituent materials, production of concrete and
compliance of concrete
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
back-propping
propping installed at levels below the slab that supports the falsework in order to distribute the load to suitable
support
3.2
chair for reinforcement
device used to secure the position between reinforcement layers, e.g. supporting top reinforcement in a slab
3.3
construction works
everything that is constructed or results from construction operations
NOTE The term covers both building and civil engineering works. It refers to the complete construction comprised of
both structural and non-structural components.
3.4
constructor
organization executing the works
3.5
erection specification
documents covering all drawings, technical data and requirements required for the safe erection of precast
elements
3.6
execution
all activities carried out for the physical completion of the work, i.e. procurement, scaffolding, formwork,
reinforcing, concreting, curing, erection of precast elements, etc., and the inspection and documentation
thereof
3.7
execution class
classified set of requirements specified for the execution of the works as a whole or an individual component
3.8
execution specification
documents covering all drawings, technical data and requirements necessary for the execution of a particular
project
NOTE The execution specification is not one document but signifies the total sum of documents required for the
execution of the work as provided by the designer to the constructor and includes the project specification prepared to
supplement and qualify the requirements of this International Standard, as well as referring to the national provisions
relevant in the place of use.
2 © ISO 2009 – All rights reserved
3.9
falsework
temporary support for a part of a structure while it is not self-supporting and for associated service load
3.10
formwork
structure, permanent or temporary, for containing poured concrete, moulding it to the required dimensions and
supporting it until it is able to support itself
NOTE Formwork consists of the face contact material and the bearers directly supporting the face contact material.
3.11
inspection
conformity evaluation by observation and judgment accompanied as appropriate by measurement, testing or
gauging
[6]
[ISO 9000:2005 , 3.8.2]
3.12
method statement
documentation describing the methods and procedures that shall be used to perform the work
3.13
permitted deviation
permitted algebraic differences between the limits of size and the corresponding reference size
[1]
[Adapted from ISO 1803:1997 , 3.8.]
3.14
precast concrete element
concrete element cast and cured in a place other than the final location of use (factory produced or site
manufactured)
NOTE Precast concrete element manufactured in compliance with the relevant international product standard is
called a “precast concrete product.” In this International Standard, the shorter terms “precast element” and “precast
product” are used.
3.15
project specification
project-specific document describing the requirements applicable for the particular project
3.16
quality plan
document specifying which procedures and associated resources shall be applied by whom and when to meet
the requirements of the specific project
[6]
NOTE Guidance can be found in ISO 9000 concerning the content of a quality plan.
3.17
reference line
line defined in the execution specification to which positions are related
3.18
secondary line
any line used for the purpose of setting-out the proposed building and for checking the compliance of the
building or building parts
[2]
[ISO 4463-1:1989 , 4.4]
3.19
spacer
device used to secure correct spacing between the formwork and the reinforcement
3.20
surface finish
description of the appearance of the concrete surface including aspects of geometry, texture, colour etc.
3.21
temporary structure
structure designed for a short design working life
3.22
tolerance
difference between upper limit of size and the lower limit of size
[1]
[Adapted from ISO 1803:1997 , 3.11.]
NOTE 1 Geometrical tolerances for precast concrete elements are subdivided as follows:
⎯ production tolerances;
⎯ erection tolerances, i.e. geometrical tolerances relating to location, verticality, horizontality or other characteristics of
the construction assembly;
⎯ construction tolerances, i.e. geometrical tolerances that are a combination of production, site construction and
erection tolerances.
NOTE 2 Tolerance is an absolute value without sign, it is however commonly expressed by “the sum of the positive
and negative permitted deviation” so that the value of the tolerance is implicit.
3.23
normal tolerance
basic limit for geometrical deviations that ensures that the structure
⎯ satisfies the design assumptions;
⎯ achieves other functional requirements of the construction works.
NOTE In this International Standard, normal tolerances are referred to as tolerance class 1.
3.24
special tolerance
tolerance other than normal tolerance
3.25
works
those parts of the construction works that are structural concrete work and are described in the execution
specification
4 Execution management
4.1 Assumptions
4.1.1 This International Standard assumes the following:
⎯ availability of a comprehensive design of the structure;
⎯ project management in charge of the supervision of the works that can enable the execution of a
conforming structure;
4 © ISO 2009 – All rights reserved
⎯ site management that can take charge of the organization of the works and enable the correct and safe
use of the equipment and machinery, the required quality of materials, the execution of a conforming
structure and its safe use up to the delivery of the works.
4.1.2 When precast elements are used, the following additional assumptions are made:
⎯ availability of a specific design of the precast elements conforming to the relevant standards;
⎯ availability of design coordination between precast elements and site manufactured components;
⎯ technical specification of the precast structure with instructions for installation;
⎯ availability of an erection management to direct the erection team.
4.1.3 This International Standard presupposes that the work is carried out with the necessary skill and
adequate equipment and resources to perform the work in accordance with this International Standard and the
requirements of the execution specification.
NOTE In some countries, there are special requirements regarding the level of knowledge, training and experience of
personnel involved in the various tasks.
4.1.4 It is assumed that the constructor will comply with national regulations and standards, e.g. with
respect to
⎯ quality management;
⎯ qualifications for the personnel doing the various activities covered by this International Standard;
⎯ health and safety aspects of construction;
⎯ environmental aspects.
4.1.5 This International Standard assumes that the structure after completion is used as intended in the
design and submitted to the planned inspection and maintenance necessary to achieve the intended design
working life and to detect weaknesses or any unexpected behaviour.
4.2 Documentation
4.2.1 Execution specification
4.2.1.1 Before commencement of the execution of any part of the works, the execution specification
relevant to that part of the works shall be complete and available.
4.2.1.2 The following items shall be included in the execution specification:
⎯ reference to this International Standard and, if published, its national annex;
⎯ reference to other relevant International Standards and national technical approvals;
⎯ reference to relevant national regulations and standards;
⎯ project specification giving information and requirements for the particular project prepared to supplement
and qualify the requirements of the above-listed documents;
⎯ drawings and other technical documents needed for the execution.
Annex H gives guidance on the content of a national annex to this International standard; a national annex
may cover any of the areas indicated as open for specification by the execution specification.
NOTE Table A.1 contains a checklist of requirements and information that it can be necessary to include in the
execution specification, as appropriate.
4.2.1.3 In addition, where relevant, procedures shall be established for
⎯ making alterations to previously agreed requirements;
⎯ distribution, filing and recording of technical documents used for the works.
4.2.2 Quality plan
4.2.2.1 Where a quality plan is required by the execution specification, it shall be available on site.
4.2.2.2 There may be one quality plan covering all activities or one overall plan supplemented by
separate plans for the various phases and activities to be performed.
4.2.3 Execution record documentation
A record shall be made giving the required information as specified for the execution class in Tables 1, 2
and 3.
4.2.4 Special record documentation
If special documentation is required, the type and extent of the documentation shall be stated in the execution
specification.
4.3 Quality management
4.3.1 Execution classes
4.3.1.1 Supervision and inspection of the work shall ensure that the construction is completed in
accordance with the execution specification.
4.3.1.2 Inspection in this context refers to verifying conformity of the properties of products and materials
being used as well as inspection of the execution of the works.
4.3.1.3 Requirements for quality management are specified using one of the following three classes, for
which the required strictness increases from class 1 to class 3:
⎯ execution class 1;
⎯ execution class 2;
⎯ execution class 3.
4.3.1.4 The execution class may refer to the complete structure, to components of the structure or to
certain materials/technologies used for the execution.
4.3.1.5 The execution class being used shall be stated in the execution specification.
4.3.1.6 This International Standard does not deal with provisions related to degree of independence of
the personnel performing the inspection.
4.3.1.7 Further detailing of the requirements for the quality management regime in excess of what is
given in this International Standard may be stated in the execution specification.
NOTE Annex B gives guidance on quality management.
6 © ISO 2009 – All rights reserved
4.3.2 Inspection of materials and products
The inspection requirements for conformity with the execution specification are given in Table 1.
Table 1 — Inspection for materials and products
Subject Execution class 1 Execution class 2 Execution class 3
Materials for scaffold,
In accordance with 5.1 and 5.2
a
formwork and falsework
a
Reinforcing steel In accordance with 6.2
Prestressing system Shall not be used in this
In accordance with 7.2
a
components class
In accordance with 8.1 and 8.3
Fresh concrete, ready-mixed
ac
or site-mixed
At reception of ready-mixed concrete a delivery ticket shall be present
ab
Other items In accordance with the execution specification
a
Precast elements In accordance with 9.2 and 9.3
Inspection report Not required Required
a
Products bearing a recognized quality mark or certified by an approved certification body shall be checked against the delivery
ticket and visually inspected. In cases of doubt, further inspection shall be undertaken to check that the product conforms to its
specification. Other products shall be subject to inspection and acceptance testing as defined in the execution specification.
b
For example, items such as embedded steel components, etc.
c
If prescribed concrete is used, the relevant properties shall be checked by tests.
4.3.3 Inspection of execution
The inspection requirements for conformity with the execution specification are given in Tables 2 and 3.
Table 2 — Inspection requirements
Subject for inspection Execution class 1 Execution class 2 Execution class 3
of execution
Scaffolding, formwork
According to requirements given in Clause 5
and falsework
Embedded items According to requirements given in 5.6
Ordinary reinforcement According to requirements given in Clause 6
Prestressing
Shall not be used in this class According to requirements given in Clause 7
reinforcement
Site transport and casting
According to requirements given in Clause 8
and curing of concrete
Erection of precast
According to requirements given in Clause 9
elements
As-built geometry Not required According to execution specification
Table 3 — Type and documentation of inspection
Execution class 1 Execution class 2 Execution class 3
Type of inspection Visual inspection and Visual inspection and Visual inspection
random measurements systematic and regular
Detailed inspection of all works
measurements of major works
which are significant for the
load-bearing capacity and
durability of the structure
Party which carries out Self inspection Self inspection Self inspection
the inspection
Inspection in accordance with Inspection in accordance with
the procedures of the the procedures of the
constructor constructor
Possible additional Additional requirements by
requirements by execution project execution specification
specification
Extent All works In addition to the self In addition to the self
inspection, there shall be a inspection, there shall be a
systematic and regular systematic and regular
inspection of the works inspection of the works
Inspection report Not required Required
As-built geometry Not required According to execution specification
4.4 Action in the event of a non-conformity
4.4.1 Where inspection reveals a non-conformity, appropriate action shall be taken to ensure that the
structure is able to perform as designed.
4.4.2 The following aspects shall be investigated in the listed order:
a) implications of the non-conformity on further execution and fitness for intended design purpose;
b) measures necessary to make the component acceptable;
c) necessity of rejection and replacement of the non-repairable component.
4.4.3 If required in the execution specification, the rectification of non-conformity shall be in accordance with
a procedure stated in the execution specification or as agreed upon.
5 Falsework and formwork
5.1 Basic requirements
5.1.1 Falsework and formwork including their supports and foundations shall be designed and constructed
so that they are
⎯ capable of resisting any foreseeable action to which they are submitted during the construction process;
⎯ stiff enough to ensure that the tolerances specified for the structure are satisfied and the integrity of the
structural member is not affected.
5.1.2 The form, function, appearance and durability of the permanent works shall not be impaired or
damaged due to the performance of the falsework, formwork and back-propping or their removal.
8 © ISO 2009 – All rights reserved
5.1.3 Falsework and formwork shall comply with this International Standard and the relevant International
Standard, if available, or be demonstrably fit for the intended use.
NOTE 1 Annex C gives guidance on falsework and formwork.
NOTE 2 Falsework and formwork that comply with International Standards prepared for systems for temporary
equipment can be deemed to satisfy this International Standard.
5.2 Materials
5.2.1 General
Any material may be used provided that its use fulfils the criteria for the structure given in 5.1 and Clause 8.
The material should comply with the relevant product standard or, where none exists, the material may be
used provided that the characteristics of the material are taken into account.
5.2.2 Release agents
5.2.2.1 Release agents, where used, shall be selected and applied in such a way that they are not harmful to
concrete, reinforcing steel, prestressing steel or formwork and in such a way that they have no detrimental
effects on the permanent structure.
5.2.2.2 Release agents shall have no unintended effect on the colour, surface quality of the permanent
structure or specified subsequent coatings.
5.3 Design and installation of falsework
5.3.1 A method statement, where required by the execution specification, shall give the design
parameters/class adopted and describe the method of erection and dismantling of temporary structures
including back-propping. It shall specify the requirements for handling, adjusting, intentional precambering,
loading, unkeying, striking and dismantling.
5.3.2 The design of the falsework shall take into account the deformation during and after concreting to
prevent deleterious cracking in the young concrete.
5.3.3 The layout of falsework shall not restrain the elastic deformation of the concrete during post-
tensioning.
5.3.4 Where the design of the finished permanent structure requires support of part of the structure until
further parts or supporting structures, including backfilling, are completed, such requirements shall be stated
in the execution specification.
5.4 Design and installation of formwork
5.4.1 A method statement, where required by the execution specification, shall describe the methods of
support, erection and dismantling. It shall specify the requirements for handling, adjusting, tying, intentional
precambering, loading, unkeying, striking and dismantling.
5.4.2 Formwork shall keep the concrete in its required shape until it is sufficiently hardened.
5.4.3 Formwork and joints shall be sufficiently tight so as to minimize loss of fines.
5.4.4 Formwork likely to absorb significant amounts of water from the concrete or facilitate evaporation shall
be suitably treated to reduce water uptake from the concrete, unless intended specifically for that purpose.
5.4.5 The internal surface of the formwork shall be clean. If the formwork is required by the execution
specification to produce visible concrete surfaces, the treatment of the formwork surfaces shall be such that
the specified finish is achievable.
5.4.6 Where the design of the finished permanent structure requires a particular surface finish, it shall be
stated in the execution specification.
5.4.7 Where the design of the finished permanent structure requires temporary support and/or specific
deflection criteria, it shall be stated in the execution specification.
5.4.8 The formwork shall not restrain the elastic deformation of the concrete during post-tensioning.
5.4.9 When using slipforming, the design of the system shall take into account the properties of the
formwork material and make provision for controlling the geometry of the works.
5.5 Special formwork
Requirements shall be given in the execution specification.
5.6 Inserts in formwork and embedded components
5.6.1 General
Temporary inserts to keep the formwork in place, such as bars, ducts and similar items, being cast within the
section and embedded components shall
⎯ be fixed robustly enough to ensure that they keep their prescribed position during concreting;
⎯ be provided with adequate corrosion protection;
⎯ be of sufficient strength and stiffness to preserve their shape during the concreting operation;
⎯ be given the specified concrete cover unless surface treated;
⎯ not introduce unacceptable actions on the structure;
⎯ not react harmfully with the concrete, the reinforcement or prestressing steel;
⎯ not produce blemishes to the specified surface finish;
⎯ not impair the functional performance and the durability of the structural member;
⎯ not prevent adequate placing and compaction of the fresh concrete.
5.6.2 Making good of temporary recesses and holes
Recesses and holes used for temporary works shall be filled and finished with a material similar in
characteristics to the surrounding concrete, or as given by the execution specification.
5.7 Removal of formwork and falsework
5.7.1 Falsework, back-propping and formwork shall not be removed until the concrete has gained sufficient
strength
⎯ to resist damage to surfaces that can arise during the striking;
⎯ to carry the actions imposed on the concrete member at that stage;
⎯ to avoid deflections beyond the specified deviation in this International Standard and the execution
specification;
⎯ to avoid damage due to climatic effects.
10 © ISO 2009 – All rights reserved
5.7.2 Striking shall be made in a manner that does not subject the structure to impact, overload or damage
the permanent structure.
5.7.3 The loads in falsework shall be released in a sequence that ensures that the other falsework
members and any supporting permanent constructions are not subject to excessive loads. The stability of
falsework and formwork shall be maintained when loads are released and during dismantling.
5.7.4 The sequence of removal, where back-propping and/or re-propping of the structure is used, shall be
detailed in a method statement or the execution specification.
5.7.5 If formwork is part of the curing system, the timing of its removal shall be taken into account in
accordance with the requirements of 8.5.
6 Reinforcement
6.1 General
Provisions given in 6.2 to 6.6 apply to pre-fabricated and site-fabricated reinforcement.
NOTE Annex D gives guidance on reinforcement.
6.2 Materials
6.2.1 Reinforcing steel shall conform to ISO 6935-1 and ISO 6935-2, and be in accordance with the
requirements given in the execution specification. Reinforcement made from stainless steel shall be in
accordance with requirements given in the execution specification.
6.2.2 Each product shall be clearly identifiable.
6.2.3 Anchorage devices and couplers shall be used as specified by the execution specification.
6.2.4 The surface of the reinforcement shall be free from loose rust and deleterious substances that can
adversely affect the steel, concrete, or the bond between them. Light surface rust is acceptable.
6.2.5 When galvanized reinforcement is used, the zinc coating shall be sufficiently passive to avoid
chemical reactions with the cement or the concrete shall be made with cement that has no detrimental effect
on the bond to the galvanized reinforcement.
NOTE Natural passivization of zinc coating can be achieved by storing the zinc-coated products outdoors for a time.
Normally about four weeks is enough. Instant passivization can be achieved by dipping the coated product in passivization
solution.
6.2.6 Materials other than steel used as reinforcement, such as composite carbon-, glass- or aramid-fibre
bars, shall have an established suitability and be in accordance with the requirements given in the execution
specification.
NOTE Suitability can be established by compliance with International Standards, national standards or national
provisions in the place of use.
6.2.7 Chairs and spacers shall be suitable for achieving the specified cover to the reinforcement. Concrete
and cementitious spacers should have at least the same strength and should give at least the same corrosion
protection as the concrete in the structure.
NOTE Steel spacers are permitted to be in contact with the concrete surface only in a dry environment, i.e. exposure
class X0 and XC1 of ISO 22965-1.
6.3 Bending, cutting, transport and storage of the reinforcement
6.3.1 The cutting and bending of reinforcing steel shall conform to the execution specification; bent bars
shall be without cracks and other damage. The following requirements apply.
⎯ Bending shall be done in one operation. When using automated bending machines, it may be continuous
or incremental.
⎯ Bending of steel at temperatures below −5 °C is permitted only if allowed by the execution specification
and provided the procedure conforms to given additional precautions.
⎯ Unless permitted by the execution specification, bending by heating the bars is not permitted.
[4]
NOTE It is recommended that bar schedules for cutting and bending of reinforcement conform to ISO 3766 .
6.3.2 For bending bars, the diameter of the mandrel used shall be in accordance with the execution
specification.
NOTE The mandrel being used is specified based on the following considerations:
⎯ the bending properties of the steel;
⎯ the bearing strength of the concrete in the bend;
⎯ geometry of the structure.
6.3.3 For welded reinforcement and fabric bent after welding, the diameter of the mandrel used shall be in
accordance with the execution specification.
6.3.4 Steel reinforcing bars, welded fabric and prefabricated reinforcement cages shall not be damaged
during transporting, storing, handling and placing into position and shall be stored clear of the ground.
6.3.5 Straightening of bent bars is not allowed unless permitted by the execution specification and, in such
cases,
⎯ the mandrel used for the original bend is at least two times the minimum mandrel allowed for that steel,
unless a smaller mandrel diameter is documented by a rebend test in accordance with ISO 15630-1;
⎯ if a smaller mandrel diameter is documented by a rebend test in accordance with ISO 15630-1, the actual
bending diameter should be not less than 1,3 times the test diameter in the rebend test;
⎯ special equipment to limit local stresses is used;
⎯ a procedure for straightening has been prepared;
⎯ straightened bars are inspected visually for cracks or other damage.
NOTE The requirements above do not exclude the use of type-tested products where the original bend is th
...
INTERNATIONAL ISO
STANDARD 22966
First edition
2009-11-15
Execution of concrete structures
Exécution des structures en béton
Reference number
©
ISO 2009
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ii © ISO 2009 – All rights reserved
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Execution management .4
4.1 Assumptions.4
4.2 Documentation .5
4.3 Quality management .6
4.4 Action in the event of a non-conformity .8
5 Falsework and formwork .8
5.1 Basic requirements .8
5.2 Materials .9
5.3 Design and installation of falsework .9
5.4 Design and installation of formwork .9
5.5 Special formwork.10
5.6 Inserts in formwork and embedded components .10
5.7 Removal of formwork and falsework.10
6 Reinforcement .11
6.1 General .11
6.2 Materials .11
6.3 Bending, cutting, transport and storage of the reinforcement.12
6.4 Welding.13
6.5 Joints .13
6.6 Assembly and placing of the reinforcement.13
7 Prestressing.13
7.1 General .13
7.2 Materials for prestressing.14
7.3 Transport and storage .15
7.4 Installation of tendons .15
7.5 Tensioning .16
7.6 Protective measures (grouting, greasing) .17
8 Concreting.18
8.1 Specification of concrete.18
8.2 Pre-concreting operations.18
8.3 Delivery, reception and site transport of fresh concrete .19
8.4 Placing and compaction .19
8.5 Curing and protection.20
8.6 Post-concreting operations.22
8.7 Concreting of composite structures .22
8.8 Surface finish.22
9 Execution with precast concrete elements.22
9.1 General .22
9.2 Factory produced precast elements.22
9.3 Site-manufactured precast elements .22
9.4 Handling and storage.23
9.5 Placing and adjustment .23
9.6 Jointing and completion works.24
10 Geometrical tolerances .24
10.1 General.24
10.2 Reference system .25
10.3 Base supports (foundations).25
10.4 Columns and walls .26
10.5 Beams and slabs.27
10.6 Sections .28
10.7 Surfaces and edge straightness .30
10.8 Tolerances for holes and inserts .30
Annex A (informative) Guidance on documentation .31
Annex B (informative) Guidance on quality management .36
Annex C (informative) Guidance on falsework and formwork.38
Annex D (informative) Guidance on reinforcement .40
Annex E (informative) Guidance on prestressing.42
Annex F (informative) Guidance on concreting .45
Annex G (informative) Guidance on geometrical tolerances.51
Annex H (informative) Guidance on national annex .58
Bibliography .59
iv © ISO 2009 – All rights reserved
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 22966 was prepared by Technical Committee ISO/TC 71, Concrete, reinforced concrete and prestressed
concrete, Subcommittee SC 3, Concrete production and execution of concrete structures.
Introduction
This International Standard applies to the execution of concrete structures to achieve the intended levels of
[3]
reliability and serviceability that are given in ISO 2394 and in standards for the design of concrete structures.
This International Standard has three functions:
⎯ to transfer the requirements set during design from the designer to the constructor, i.e. to be a link
between design and execution;
⎯ to give a set of standardized technical requirements for the execution when ordering a concrete structure;
⎯ to serve as a check list for the designer to ensure that he provides the constructor with all relevant
technical information for the execution of the structure; see Annex A.
In order to achieve these objectives, it is necessary that the designer prepare a set of documents and
drawings giving all information required for the execution of the work in accordance with the plans. This set of
documents is in this International Standard referred to as the “execution specification”. This International
Standard leaves a number of items open that can be decided by the execution specification.
It is necessary that the execution specification refer to national provisions in areas where these apply.
It is recognized in this International Standard that areas such as detailed requirements for competence of
personnel and details related to quality management are within the competence of the member states.
A national annex can refer to national standards approved and published by an ISO member body and that
supplement this International Standard; alternatively, the supplementing rules can be given directly in the
national annex.
vi © ISO 2009 – All rights reserved
INTERNATIONAL STANDARD ISO 22966:2009(E)
Execution of concrete structures
1 Scope
This International Standard gives common requirements for the execution of concrete structures and applies
to both in-situ works and construction using prefabricated concrete elements.
This International Standard requires that the execution specification state all the specific requirements
relevant to the particular structure.
This International Standard is applicable to temporary as well as permanent concrete structures.
Additional or different requirements can be considered and, if required, given in the execution specification
when using
⎯ lightweight aggregate concrete;
⎯ other materials (e.g. fibres) or constituent materials;
⎯ special technologies/innovative designs.
This International Standard does not apply to the following:
a) concrete members used only as equipment or construction aids for the execution;
b) specification, production and conformity of concrete;
c) production of precast concrete elements made in accordance with product standards;
d) safety and health aspects of execution, or third-party safety requirements;
e) contractual issues or responsibilities for the identified actions.
2 Normative references
The following referenced documents are indispensable for the application 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 6934 (all parts), Steel for the prestressing of concrete
ISO 6935-1, Steel for the reinforcement of concrete — Part 1: Plain bars
ISO 6935-2, Steel for the reinforcement of concrete — Part 2: Ribbed bars
ISO 15630-1, Steel for the reinforcement and prestressing of concrete — Test methods — Part 1: Reinforcing
bars, wire rod and wire
ISO 17660-1, Welding — Welding of reinforcing steel — Part 1: Load-bearing welded joints
ISO 17660-2, Welding — Welding of reinforcing steel — Part 2: Non-load-bearing welded joints
ISO 22965-1, Concrete — Part 1: Methods of specifying and guidance for the specifier
ISO 22965-2, Concrete — Part 2; Specification of constituent materials, production of concrete and
compliance of concrete
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
back-propping
propping installed at levels below the slab that supports the falsework in order to distribute the load to suitable
support
3.2
chair for reinforcement
device used to secure the position between reinforcement layers, e.g. supporting top reinforcement in a slab
3.3
construction works
everything that is constructed or results from construction operations
NOTE The term covers both building and civil engineering works. It refers to the complete construction comprised of
both structural and non-structural components.
3.4
constructor
organization executing the works
3.5
erection specification
documents covering all drawings, technical data and requirements required for the safe erection of precast
elements
3.6
execution
all activities carried out for the physical completion of the work, i.e. procurement, scaffolding, formwork,
reinforcing, concreting, curing, erection of precast elements, etc., and the inspection and documentation
thereof
3.7
execution class
classified set of requirements specified for the execution of the works as a whole or an individual component
3.8
execution specification
documents covering all drawings, technical data and requirements necessary for the execution of a particular
project
NOTE The execution specification is not one document but signifies the total sum of documents required for the
execution of the work as provided by the designer to the constructor and includes the project specification prepared to
supplement and qualify the requirements of this International Standard, as well as referring to the national provisions
relevant in the place of use.
2 © ISO 2009 – All rights reserved
3.9
falsework
temporary support for a part of a structure while it is not self-supporting and for associated service load
3.10
formwork
structure, permanent or temporary, for containing poured concrete, moulding it to the required dimensions and
supporting it until it is able to support itself
NOTE Formwork consists of the face contact material and the bearers directly supporting the face contact material.
3.11
inspection
conformity evaluation by observation and judgment accompanied as appropriate by measurement, testing or
gauging
[6]
[ISO 9000:2005 , 3.8.2]
3.12
method statement
documentation describing the methods and procedures that shall be used to perform the work
3.13
permitted deviation
permitted algebraic differences between the limits of size and the corresponding reference size
[1]
[Adapted from ISO 1803:1997 , 3.8.]
3.14
precast concrete element
concrete element cast and cured in a place other than the final location of use (factory produced or site
manufactured)
NOTE Precast concrete element manufactured in compliance with the relevant international product standard is
called a “precast concrete product.” In this International Standard, the shorter terms “precast element” and “precast
product” are used.
3.15
project specification
project-specific document describing the requirements applicable for the particular project
3.16
quality plan
document specifying which procedures and associated resources shall be applied by whom and when to meet
the requirements of the specific project
[6]
NOTE Guidance can be found in ISO 9000 concerning the content of a quality plan.
3.17
reference line
line defined in the execution specification to which positions are related
3.18
secondary line
any line used for the purpose of setting-out the proposed building and for checking the compliance of the
building or building parts
[2]
[ISO 4463-1:1989 , 4.4]
3.19
spacer
device used to secure correct spacing between the formwork and the reinforcement
3.20
surface finish
description of the appearance of the concrete surface including aspects of geometry, texture, colour etc.
3.21
temporary structure
structure designed for a short design working life
3.22
tolerance
difference between upper limit of size and the lower limit of size
[1]
[Adapted from ISO 1803:1997 , 3.11.]
NOTE 1 Geometrical tolerances for precast concrete elements are subdivided as follows:
⎯ production tolerances;
⎯ erection tolerances, i.e. geometrical tolerances relating to location, verticality, horizontality or other characteristics of
the construction assembly;
⎯ construction tolerances, i.e. geometrical tolerances that are a combination of production, site construction and
erection tolerances.
NOTE 2 Tolerance is an absolute value without sign, it is however commonly expressed by “the sum of the positive
and negative permitted deviation” so that the value of the tolerance is implicit.
3.23
normal tolerance
basic limit for geometrical deviations that ensures that the structure
⎯ satisfies the design assumptions;
⎯ achieves other functional requirements of the construction works.
NOTE In this International Standard, normal tolerances are referred to as tolerance class 1.
3.24
special tolerance
tolerance other than normal tolerance
3.25
works
those parts of the construction works that are structural concrete work and are described in the execution
specification
4 Execution management
4.1 Assumptions
4.1.1 This International Standard assumes the following:
⎯ availability of a comprehensive design of the structure;
⎯ project management in charge of the supervision of the works that can enable the execution of a
conforming structure;
4 © ISO 2009 – All rights reserved
⎯ site management that can take charge of the organization of the works and enable the correct and safe
use of the equipment and machinery, the required quality of materials, the execution of a conforming
structure and its safe use up to the delivery of the works.
4.1.2 When precast elements are used, the following additional assumptions are made:
⎯ availability of a specific design of the precast elements conforming to the relevant standards;
⎯ availability of design coordination between precast elements and site manufactured components;
⎯ technical specification of the precast structure with instructions for installation;
⎯ availability of an erection management to direct the erection team.
4.1.3 This International Standard presupposes that the work is carried out with the necessary skill and
adequate equipment and resources to perform the work in accordance with this International Standard and the
requirements of the execution specification.
NOTE In some countries, there are special requirements regarding the level of knowledge, training and experience of
personnel involved in the various tasks.
4.1.4 It is assumed that the constructor will comply with national regulations and standards, e.g. with
respect to
⎯ quality management;
⎯ qualifications for the personnel doing the various activities covered by this International Standard;
⎯ health and safety aspects of construction;
⎯ environmental aspects.
4.1.5 This International Standard assumes that the structure after completion is used as intended in the
design and submitted to the planned inspection and maintenance necessary to achieve the intended design
working life and to detect weaknesses or any unexpected behaviour.
4.2 Documentation
4.2.1 Execution specification
4.2.1.1 Before commencement of the execution of any part of the works, the execution specification
relevant to that part of the works shall be complete and available.
4.2.1.2 The following items shall be included in the execution specification:
⎯ reference to this International Standard and, if published, its national annex;
⎯ reference to other relevant International Standards and national technical approvals;
⎯ reference to relevant national regulations and standards;
⎯ project specification giving information and requirements for the particular project prepared to supplement
and qualify the requirements of the above-listed documents;
⎯ drawings and other technical documents needed for the execution.
Annex H gives guidance on the content of a national annex to this International standard; a national annex
may cover any of the areas indicated as open for specification by the execution specification.
NOTE Table A.1 contains a checklist of requirements and information that it can be necessary to include in the
execution specification, as appropriate.
4.2.1.3 In addition, where relevant, procedures shall be established for
⎯ making alterations to previously agreed requirements;
⎯ distribution, filing and recording of technical documents used for the works.
4.2.2 Quality plan
4.2.2.1 Where a quality plan is required by the execution specification, it shall be available on site.
4.2.2.2 There may be one quality plan covering all activities or one overall plan supplemented by
separate plans for the various phases and activities to be performed.
4.2.3 Execution record documentation
A record shall be made giving the required information as specified for the execution class in Tables 1, 2
and 3.
4.2.4 Special record documentation
If special documentation is required, the type and extent of the documentation shall be stated in the execution
specification.
4.3 Quality management
4.3.1 Execution classes
4.3.1.1 Supervision and inspection of the work shall ensure that the construction is completed in
accordance with the execution specification.
4.3.1.2 Inspection in this context refers to verifying conformity of the properties of products and materials
being used as well as inspection of the execution of the works.
4.3.1.3 Requirements for quality management are specified using one of the following three classes, for
which the required strictness increases from class 1 to class 3:
⎯ execution class 1;
⎯ execution class 2;
⎯ execution class 3.
4.3.1.4 The execution class may refer to the complete structure, to components of the structure or to
certain materials/technologies used for the execution.
4.3.1.5 The execution class being used shall be stated in the execution specification.
4.3.1.6 This International Standard does not deal with provisions related to degree of independence of
the personnel performing the inspection.
4.3.1.7 Further detailing of the requirements for the quality management regime in excess of what is
given in this International Standard may be stated in the execution specification.
NOTE Annex B gives guidance on quality management.
6 © ISO 2009 – All rights reserved
4.3.2 Inspection of materials and products
The inspection requirements for conformity with the execution specification are given in Table 1.
Table 1 — Inspection for materials and products
Subject Execution class 1 Execution class 2 Execution class 3
Materials for scaffold,
In accordance with 5.1 and 5.2
a
formwork and falsework
a
Reinforcing steel In accordance with 6.2
Prestressing system Shall not be used in this
In accordance with 7.2
a
components class
In accordance with 8.1 and 8.3
Fresh concrete, ready-mixed
ac
or site-mixed
At reception of ready-mixed concrete a delivery ticket shall be present
ab
Other items In accordance with the execution specification
a
Precast elements In accordance with 9.2 and 9.3
Inspection report Not required Required
a
Products bearing a recognized quality mark or certified by an approved certification body shall be checked against the delivery
ticket and visually inspected. In cases of doubt, further inspection shall be undertaken to check that the product conforms to its
specification. Other products shall be subject to inspection and acceptance testing as defined in the execution specification.
b
For example, items such as embedded steel components, etc.
c
If prescribed concrete is used, the relevant properties shall be checked by tests.
4.3.3 Inspection of execution
The inspection requirements for conformity with the execution specification are given in Tables 2 and 3.
Table 2 — Inspection requirements
Subject for inspection Execution class 1 Execution class 2 Execution class 3
of execution
Scaffolding, formwork
According to requirements given in Clause 5
and falsework
Embedded items According to requirements given in 5.6
Ordinary reinforcement According to requirements given in Clause 6
Prestressing
Shall not be used in this class According to requirements given in Clause 7
reinforcement
Site transport and casting
According to requirements given in Clause 8
and curing of concrete
Erection of precast
According to requirements given in Clause 9
elements
As-built geometry Not required According to execution specification
Table 3 — Type and documentation of inspection
Execution class 1 Execution class 2 Execution class 3
Type of inspection Visual inspection and Visual inspection and Visual inspection
random measurements systematic and regular
Detailed inspection of all works
measurements of major works
which are significant for the
load-bearing capacity and
durability of the structure
Party which carries out Self inspection Self inspection Self inspection
the inspection
Inspection in accordance with Inspection in accordance with
the procedures of the the procedures of the
constructor constructor
Possible additional Additional requirements by
requirements by execution project execution specification
specification
Extent All works In addition to the self In addition to the self
inspection, there shall be a inspection, there shall be a
systematic and regular systematic and regular
inspection of the works inspection of the works
Inspection report Not required Required
As-built geometry Not required According to execution specification
4.4 Action in the event of a non-conformity
4.4.1 Where inspection reveals a non-conformity, appropriate action shall be taken to ensure that the
structure is able to perform as designed.
4.4.2 The following aspects shall be investigated in the listed order:
a) implications of the non-conformity on further execution and fitness for intended design purpose;
b) measures necessary to make the component acceptable;
c) necessity of rejection and replacement of the non-repairable component.
4.4.3 If required in the execution specification, the rectification of non-conformity shall be in accordance with
a procedure stated in the execution specification or as agreed upon.
5 Falsework and formwork
5.1 Basic requirements
5.1.1 Falsework and formwork including their supports and foundations shall be designed and constructed
so that they are
⎯ capable of resisting any foreseeable action to which they are submitted during the construction process;
⎯ stiff enough to ensure that the tolerances specified for the structure are satisfied and the integrity of the
structural member is not affected.
5.1.2 The form, function, appearance and durability of the permanent works shall not be impaired or
damaged due to the performance of the falsework, formwork and back-propping or their removal.
8 © ISO 2009 – All rights reserved
5.1.3 Falsework and formwork shall comply with this International Standard and the relevant International
Standard, if available, or be demonstrably fit for the intended use.
NOTE 1 Annex C gives guidance on falsework and formwork.
NOTE 2 Falsework and formwork that comply with International Standards prepared for systems for temporary
equipment can be deemed to satisfy this International Standard.
5.2 Materials
5.2.1 General
Any material may be used provided that its use fulfils the criteria for the structure given in 5.1 and Clause 8.
The material should comply with the relevant product standard or, where none exists, the material may be
used provided that the characteristics of the material are taken into account.
5.2.2 Release agents
5.2.2.1 Release agents, where used, shall be selected and applied in such a way that they are not harmful to
concrete, reinforcing steel, prestressing steel or formwork and in such a way that they have no detrimental
effects on the permanent structure.
5.2.2.2 Release agents shall have no unintended effect on the colour, surface quality of the permanent
structure or specified subsequent coatings.
5.3 Design and installation of falsework
5.3.1 A method statement, where required by the execution specification, shall give the design
parameters/class adopted and describe the method of erection and dismantling of temporary structures
including back-propping. It shall specify the requirements for handling, adjusting, intentional precambering,
loading, unkeying, striking and dismantling.
5.3.2 The design of the falsework shall take into account the deformation during and after concreting to
prevent deleterious cracking in the young concrete.
5.3.3 The layout of falsework shall not restrain the elastic deformation of the concrete during post-
tensioning.
5.3.4 Where the design of the finished permanent structure requires support of part of the structure until
further parts or supporting structures, including backfilling, are completed, such requirements shall be stated
in the execution specification.
5.4 Design and installation of formwork
5.4.1 A method statement, where required by the execution specification, shall describe the methods of
support, erection and dismantling. It shall specify the requirements for handling, adjusting, tying, intentional
precambering, loading, unkeying, striking and dismantling.
5.4.2 Formwork shall keep the concrete in its required shape until it is sufficiently hardened.
5.4.3 Formwork and joints shall be sufficiently tight so as to minimize loss of fines.
5.4.4 Formwork likely to absorb significant amounts of water from the concrete or facilitate evaporation shall
be suitably treated to reduce water uptake from the concrete, unless intended specifically for that purpose.
5.4.5 The internal surface of the formwork shall be clean. If the formwork is required by the execution
specification to produce visible concrete surfaces, the treatment of the formwork surfaces shall be such that
the specified finish is achievable.
5.4.6 Where the design of the finished permanent structure requires a particular surface finish, it shall be
stated in the execution specification.
5.4.7 Where the design of the finished permanent structure requires temporary support and/or specific
deflection criteria, it shall be stated in the execution specification.
5.4.8 The formwork shall not restrain the elastic deformation of the concrete during post-tensioning.
5.4.9 When using slipforming, the design of the system shall take into account the properties of the
formwork material and make provision for controlling the geometry of the works.
5.5 Special formwork
Requirements shall be given in the execution specification.
5.6 Inserts in formwork and embedded components
5.6.1 General
Temporary inserts to keep the formwork in place, such as bars, ducts and similar items, being cast within the
section and embedded components shall
⎯ be fixed robustly enough to ensure that they keep their prescribed position during concreting;
⎯ be provided with adequate corrosion protection;
⎯ be of sufficient strength and stiffness to preserve their shape during the concreting operation;
⎯ be given the specified concrete cover unless surface treated;
⎯ not introduce unacceptable actions on the structure;
⎯ not react harmfully with the concrete, the reinforcement or prestressing steel;
⎯ not produce blemishes to the specified surface finish;
⎯ not impair the functional performance and the durability of the structural member;
⎯ not prevent adequate placing and compaction of the fresh concrete.
5.6.2 Making good of temporary recesses and holes
Recesses and holes used for temporary works shall be filled and finished with a material similar in
characteristics to the surrounding concrete, or as given by the execution specification.
5.7 Removal of formwork and falsework
5.7.1 Falsework, back-propping and formwork shall not be removed until the concrete has gained sufficient
strength
⎯ to resist damage to surfaces that can arise during the striking;
⎯ to carry the actions imposed on the concrete member at that stage;
⎯ to avoid deflections beyond the specified deviation in this International Standard and the execution
specification;
⎯ to avoid damage due to climatic effects.
10 © ISO 2009 – All rights reserved
5.7.2 Striking shall be made in a manner that does not subject the structure to impact, overload or damage
the permanent structure.
5.7.3 The loads in falsework shall be released in a sequence that ensures that the other falsework
members and any supporting permanent constructions are not subject to excessive loads. The stability of
falsework and formwork shall be maintained when loads are released and during dismantling.
5.7.4 The sequence of removal, where back-propping and/or re-propping of the structure is used, shall be
detailed in a method statement or the execution specification.
5.7.5 If formwork is part of the curing system, the timing of its removal shall be taken into account in
accordance with the requirements of 8.5.
6 Reinforcement
6.1 General
Provisions given in 6.2 to 6.6 apply to pre-fabricated and site-fabricated reinforcement.
NOTE Annex D gives guidance on reinforcement.
6.2 Materials
6.2.1 Reinforcing steel shall conform to ISO 6935-1 and ISO 6935-2, and be in accordance with the
requirements given in the execution specification. Reinforcement made from stainless steel shall be in
accordance with requirements given in the execution specification.
6.2.2 Each product shall be clearly identifiable.
6.2.3 Anchorage devices and couplers shall be used as specified by the execution specification.
6.2.4 The surface of the reinforcement shall be free from loose rust and deleterious substances that can
adversely affect the steel, concrete, or the bond between them. Light surface rust is acceptable.
6.2.5 When galvanized reinforcement is used, the zinc coating shall be sufficiently passive to avoid
chemical reactions with the cement or the concrete shall be made with cement that has no detrimental effect
on the bond to the galvanized reinforcement.
NOTE Natural passivization of zinc coating can be achieved by storing the zinc-coated products outdoors for a time.
Normally about four weeks is enough. Instant passivization can be achieved by dipping the coated product in passivization
solution.
6.2.6 Materials other than steel used as reinforcement, such as composite carbon-, glass- or aramid-fibre
bars, shall have an established suitability and be in accordance with the requirements given in the execution
specification.
NOTE Suitability can be established by compliance with International Standards, national standards or national
provisions in the place of use.
6.2.7 Chairs and spacers shall be suitable for achieving the specified cover to the reinforcement. Concrete
and cementitious spacers should have at least the same strength and should give at least the same corrosion
protection as the concrete in the structure.
NOTE Steel spacers are permitted to be in contact with the concrete surface only in a dry environment, i.e. exposure
class X0 and XC1 of ISO 22965-1.
6.3 Bending, cutting, transport and storage of the reinforcement
6.3.1 The cutting and bending of reinforcing steel shall conform to the execution specification; bent bars
shall be without cracks and other damage. The following requirements apply.
⎯ Bending shall be done in one operation. When using automated bending machines, it may be continuous
or incremental.
⎯ Bending of steel at temperatures below −5 °C is permitted only if allowed by the execution specification
and provided the procedure conforms to given additional precautions.
⎯ Unless permitted by the execution specification, bending by heating the bars is not permitted.
[4]
NOTE It is recommended that bar schedules for cutting and bending of reinforcement conform to ISO 3766 .
6.3.2 For bending bars, the diameter of the mandrel used shall be in accordance with the execution
specification.
NOTE The mandrel being used is specified based on the following considerations:
⎯ the bending properties of the steel;
⎯ the bearing strength of the concrete in the bend;
⎯ geometry of the structure.
6.3.3 For welded reinforcement and fabric bent after welding, the diameter of the mandrel used shall be in
accordance with the execution specification.
6.3.4 Steel reinforcing bars, welded fabric and prefabricated reinforcement cages shall not be damaged
during transporting, storing, handling and placing into position and shall be stored clear of the ground.
6.3.5 Straightening of bent bars is not allowed unless permitted by the execution specification and, in such
cases,
⎯ the mandrel used for the original bend is at least two times the minimum mandrel allowed for that steel,
unless a smaller mandrel diameter is documented by a rebend test in accordance with ISO 15630-1;
⎯ if a smaller mandrel diameter is documented by a rebend test in accordance with ISO 15630-1, the actual
bending diameter should be not less than 1,3 times the test diameter in the rebend test;
⎯ special equipment to limit local stresses is used;
⎯ a procedure for straightening has been prepared;
⎯ straightened bars are inspected visually for cracks or other damage.
NOTE The requirements above do not exclude the use of type-tested products where the original bend is that which
can be documented by a test of tensile strength, demonstrating a tensile strength as required for the actual grade of steel,
after a procedure of bending, aging and straightening.
6.3.6 Reinforcement from coils shall not be used unless appropriate equipment is available and the
straightening procedures are in accordance with the manufacturer's instructions. The de-coiled and
straightened bars shall meet the requirements for the reinforcement given in the relevant standards, after
straightening, and tested as specified in ISO 6935-1 and ISO 6935-2.
12 © ISO 2009 – All rights reserved
6.4 Welding
6.4.1 Welding is permitted only on reinforcing steel classified as weldable, unless specified in the execution
specification.
6.4.2 Welding of reinforcing steel and welding of reinforcing steel to structural steel in loadbearing joints
...
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