ISO 22156:2021
(Main)Bamboo structures — Bamboo culms — Structural design
Bamboo structures — Bamboo culms — Structural design
This document applies to the design of bamboo structures whose primary load bearing structure is made of round bamboo or shear panel systems in which the framing members are made from round bamboo. Except as indicated in Clause 12, this document applies to one- and two-storey residential, small commercial or institutional and light industrial buildings not exceeding 7 m in height. This document is concerned only with requirements for mechanical resistance, serviceability and durability of bamboo structures. This document permits an allowable load-bearing capacity design (ACD) and/or allowable stress design (ASD) approach for the design of bamboo structures. Allowable load-bearing capacity and allowable stress approaches may be used in combination in the same structure. This document additionally recognises design approaches based on partial safety factor design (PSFD) and/or load and resistance factor design (LRFD) methods (5.11.1), previous established experience (5.11.2), or documented ‘design by testing’ approaches (5.11.3). Other requirements, such as those concerning thermal or sound insulation, are not considered. Bamboo structures may require consideration of additional requirements beyond the scope of this document. Execution is covered to the extent that it impacts the quality of construction materials and products required to comply with the design requirements contained herein. This document provides a number of modification factors, designated Ci. These are empirically derived factors, based on best available engineering judgement, that are believed to be universally applicable to bamboo materials that are appropriate for building construction. Parameters affecting bamboo material performance are many and are addressed explicitly through the use of experimentally determined characteristic values of strength and stiffness. Annex A provides a summary of the bases upon which the provisions of this document were developed. This document does not apply to — structures made of engineered bamboo products such as glue-laminated bamboo, cross-laminated bamboo, oriented strand, or densified bamboo materials, — bamboo-reinforced materials where bamboo is not the primary load-bearing constituent. This includes bamboo-reinforced concrete, masonry and soil, or, — scaffold structures constructed with bamboo.
Structures en bambou — Tiges de bambou — Conception des structures
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INTERNATIONAL ISO
STANDARD 22156
Second edition
2021-06
Bamboo structures — Bamboo culms
— Structural design
Structures en bambou — Tiges de bambou — Conception des
structures
Reference number
ISO 22156:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 22156:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22156:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 4
5 Basic requirements of design . 6
5.1 General . 6
5.2 Design methodology. 7
5.3 Susceptibility to splitting . 7
5.4 Redundancy . 7
5.4.1 Non-redundant structural members . 7
5.4.2 Redundant structural members . 7
5.5 Serviceability considerations . 8
5.6 Service classes . 8
5.6.1 Service class 1 . 8
5.6.2 Service class 2 . 8
5.6.3 Service class 3 . 8
5.7 Durability . 8
5.7.1 Use classes . 9
5.7.2 Resistance to corrosion of metallic elements .10
5.8 Effects of elevated temperature .10
5.9 Maintenance, inspectability and replacement considerations .10
5.10 Seismic force reduction factor for bamboo structures .10
5.11 Alternate design methodologies .10
5.11.1 Partial safety factor design (PSFD) or load and resistance factor design
(LRFD) methodology .10
5.11.2 Experience from Previous Generations .10
5.11.3 Design by testing .11
6 Member component and material properties .11
6.1 General .11
6.2 Characteristic material and component properties .12
6.3 Allowable member design capacity .12
6.4 Allowable design strength .13
6.4.1 Culm geometry for use with allowable design strength .14
6.5 Component flexural stiffness .15
6.6 Modulus of elasticity .15
7 Structural modelling bamboo structures .15
8 Flexural members (beams) .16
8.1 General .16
8.2 Multiple culm flexural members .16
8.2.1 Bracing requirements for multiple culm flexural members .17
8.3 Flexural member capacity .17
8.3.1 Flexural capacity determined from component capacity .17
8.3.2 Flexural capacity determined from bending strength .18
8.4 Calculation of deflection .18
8.4.1 Flexural stiffness determined from component properties .19
8.4.2 Flexural stiffness determined from material and geometric properties .19
8.4.3 Long term deflections .19
9 Axial load carrying members .19
9.1 General .19
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 22156:2021(E)
9.2 Compression member effective length.20
9.2.1 Lateral restraint of compression members .20
9.3 Compression capacity .21
9.3.1 Compression capacity from geometric and material properties .21
9.3.2 Crushing capacity .21
9.3.3 Buckling capacity . .22
9.4 Tension capacity .22
9.4.1 Tension capacity from component capacity .22
9.4.2 Tension capacity from geometric and material properties .23
9.5 Combined axial and flexural loads .23
10 Joints and splices .23
10.1 General .23
10.2 Design properties by complete joint testing .24
10.3 Design properties by component capacities .24
10.4 Allowable joint design capacity .24
10.5 Joint stiffness .25
10.6 Ductility of joints .25
10.7 Robustness against culm splitting .25
10.7.1 Radial clamping to resist splitting .26
10.8 Splices joints .26
10.9 Requirements for non-bamboo components of joints .26
10.9.1 Metallic components of joints .26
10.9.2 Joints utilising flowable infill material (grouted joints) .26
10.9.3 Lashing .27
10.9.4 Mechanical and proprietary joint systems .27
10.10 End bearing capacity of bamboo culms .27
10.11 Circumferential bearing capacity of bamboo culms .27
10.12 Joints having through culm wall dowels .29
10.12.1 Capacity of single dowel .29
10.12.2 Requirements for dowels .31
10.12.3 Tension forces on dowel joints .31
11 Trusses .31
12 Shear panels (walls) .32
12.1 General .32
12.1.1 Openings in panels .32
12.2 Loads . .33
12.2.1 Out-of-plane loads .33
12.2.2 In-plane loads .34
12.2.3 Gravity loads .35
12.3 Determination of design strengths .35
13 Fire resistance .36
14 Structural grading .36
15 Quality assessment and control.36
Annex A (informative) Bases of provisions in this document.37
Annex B (informative) Durability and preservation recommendations .38
Annex C (informative) Examples of seismic and alternative design factors .40
Annex D (informative) Examples and classification of bamboo connections and joints .41
Annex E (informative) Design of LCBF components to satisfy requirements of 12 .45
Bibliography .48
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22156:2021(E)
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 165, Timber structures
This second edition cancels and replaces the first edition (ISO 22156:2004), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— adoption of design equations for material or component capacities for both members and joints;
— adoption of service classes and specific consideration of susceptibility to splitting;
— addition of Light Cement Bamboo Frame (LCBF) construction;
— addition of informative annexes addressing durability and representative details for connections
and LCBF construction;
— removal of use of bamboo for reinforcing concrete or soil.
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.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 22156:2021(E)
Introduction
This document provides a means of structural design for one- and two-storey building structures using
full-culm round bamboo poles as the primary vertical and horizontal structural load resisting systems.
This document addresses connection design, light cement bamboo frame shear panel design, and
addresses issues of durability. Informative annexes provide means of achieving design and performance
goals in these areas.
vi © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22156:2021(E)
Bamboo structures — Bamboo culms — Structural design
1 Scope
This document applies to the design of bamboo structures whose primary load bearing structure is
made of round bamboo or shear panel systems in which the framing members are made from round
bamboo.
Except as indicated in Clause 12, this document applies to one- and two-storey residential, small
commercial or institutional and light industrial buildings not exceeding 7 m in height.
This document is concerned only with requirements for mechanical resistance, serviceability and
durability of bamboo structures.
This document permits an allowable load-bearing capacity design (ACD) and/or allowable stress design
(ASD) approach for the design of bamboo structures. Allowable load-bearing capacity and allowable
stress approaches may be used in combination in the same structure.
This document additionally recognises design approaches based on partial safety factor design (PSFD)
and/or load and resistance factor design (LRFD) methods (5.11.1), previous established experience
(5.11.2), or documented ‘design by testing’ approaches (5.11.3).
Other requirements, such as those concerning thermal or sound insulation, are not considered. Bamboo
structures may require consideration of additional requirements beyond the scope of this document.
Execution is covered to the extent that it impacts the quality of construction materials and products
required to comply with the design requirements contained herein.
This document provides a number of modification factors, designated C . These are empirically derived
i
factors, based on best available engineering judgement, that are believed to be universally applicable
to bamboo materials that are appropriate for building construction. Parameters affecting bamboo
material performance are many and are addressed explicitly through the use of experimentally
determined characteristic values of strength and stiffness. Annex A provides a summary of the bases
upon which the provisions of this document were developed.
This document does not apply to
— structures made of engineered bamboo products such as glue-laminated bamboo, cross-laminated
bamboo, oriented strand, or densified bamboo materials,
— bamboo-reinforced materials where bamboo is not the primary load-bearing constituent. This
includes bamboo-reinforced concrete, masonry and soil, or,
— scaffold structures constructed with bamboo.
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 12122-1, Timber structures — Determination of characteristic values — Part 1: Basic requirements
ISO 12122-5, Timber structures — Determination of characteristic values — Part 5: Mechanical connections
ISO 12122-6, Timber structures — Determination of characteristic values — Part 6: Large components
and assemblies
© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 22156:2021(E)
ISO 16670, Timber structures — Joints made with mechanical fasteners — Quasi-static reversed-cyclic test
method
ISO 19624, Bamboo structures — Grading of bamboo culms — Basic principles and procedures
ISO 21581:2010, Timber structures - Static and cyclic lateral load test methods for shear walls
ISO 21887, Durability of wood and wood-based products — Use classes
ISO 22157, Bamboo structures — Determination of physical and mechanical properties of bamboo culms —
Test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
assembly
multiple-culm assembly
structural member comprised of more than one bamboo culm constructed in such a fashion that the
multiple culms together serve as a single structural member
3.2
bamboo culm
bamboo pole
single shoot of bamboo
Note 1 to entry: A culm is comprised of the entire unaltered bamboo cross section and is usually a hollow cylinder
except at nodes.
3.3
cross sectional area
A
area of the section perpendicular to the direction of the longitudinal axis of the culm
3.4
ductility
μ
ratio of the experimentally determined ultimate displacement to the yield displacement
1)
Note 1 to entry: The ratio is determined according to ISO/CD TR 21141 for joints.
3.5
equilibrium moisture content
w
EMC
moisture content at which bamboo is neither gaining moisture from, nor losing moisture to, the
environment
3.6
fibre saturation point
w
FSP
moisture content below which only water bound in the cell walls remains; i.e., condition in which there
is no free water in the cell cavities
1) In preparation. Stage at the time of publication ISO/CD TR 21141:2021.
2 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 22156:2021(E)
3.7
flattened bamboo
element obtained by opening the bamboo culm and making longitudinal cuts (scores) partially through
the culm wall to make a flat member
Note 1 to entry: Flattened bamboo is often referred to as “esterilla”.
3.8
internode
typically hollow region of bamboo culm between two nodes
3.9
joint
connection of two or more bamboo members
3.10
lashing
means of connecting bamboo culms by continuous wrapping of material around culm and joint region
3.11
light cement bamboo frame
LCBF
improved vernacular construction technique originating in Latin America utilising shear walls
constituted from a cement mortar render applied onto strip, flattened or small diameter bamboo, which
are fixed onto bamboo and/or timber studs or framing
Note 1 to entry: The cement mortar render is reinforced by a small-gauge metal mesh such as “chicken wire”. An
alternative technique in which the cement mortar render is applied directly onto expanded metal lath sheets,
which are in turn fixed onto the frame, is also accepted. The system is also known as "bahareque encementado"
and composite bamboo shear walls.
3.12
moisture content
w
portion of culm weight consisting of water expressed as percentage of oven-dry weight
3.13
node
transverse diaphragm region located along length of culm separating adjacent internodes
3.14
non-redundant
structural member is non-redundant if there is no alternative and sufficient load path in the structure
to transmit the load carried by the member in the event of its removal (member failure) from the load
path
Note 1 to entry: Failure of a non-redundant member leads to failure of the load path in which it is a part.
3.15
outer diameter
D
diameter of the cross section of a piece of bamboo, typically made near the centre of an internode, taken
as the average of two perpendicular measurements made across opposite points on the outer surface or
calculated from a measurement of the perimeter
3.16
point of contraflexure
point of inflection
location of zero moment where the curvature of the member is zero
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 22156:2021(E)
3.17
shear span
distance between the maximum moment and the nearest point of contraflexure
(3.16)
Note 1 to entry: Shear span is conventionally assumed to be equal to half the span for
...
INTERNATIONAL ISO
STANDARD 22156
Second edition
Bamboo structures — Bamboo culms
— Structural design
Structures en bambou — Tiges de bambou — Conception des
structures
PROOF/ÉPREUVE
Reference number
ISO 22156:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 22156:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22156:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 4
5 Basic requirements of design . 6
5.1 General . 6
5.2 Design methodology. 7
5.3 Susceptibility to splitting . 7
5.4 Redundancy . 7
5.4.1 Non-redundant structural members . 7
5.4.2 Redundant structural members . 7
5.5 Serviceability considerations . 8
5.6 Service classes . 8
5.6.1 Service class 1 . 8
5.6.2 Service class 2 . 8
5.6.3 Service class 3 . 8
5.7 Durability . 8
5.7.1 Use classes . 9
5.7.2 Resistance to corrosion of metallic elements .10
5.8 Effects of elevated temperature .10
5.9 Maintenance, inspectability and replacement considerations .10
5.10 Seismic force reduction factor for bamboo structures .10
5.11 Alternate design methodologies .10
5.11.1 Partial safety factor design (PSFD) or load and resistance factor design
(LRFD) methodology .10
5.11.2 Experience from Previous Generations .10
5.11.3 Design by testing .11
6 Member component and material properties .11
6.1 General .11
6.2 Characteristic material and component properties .12
6.3 Allowable member design capacity .12
6.4 Allowable design strength .13
6.4.1 Culm geometry for use with allowable design strength .14
6.5 Component flexural stiffness .15
6.6 Modulus of elasticity .15
7 Structural modelling bamboo structures .15
8 Flexural members (beams) .16
8.1 General .16
8.2 Multiple culm flexural members .16
8.2.1 Bracing requirements for multiple culm flexural members .17
8.3 Flexural member capacity .17
8.3.1 Flexural capacity determined from component capacity .17
8.3.2 Flexural capacity determined from bending strength .18
8.4 Calculation of deflection .18
8.4.1 Flexural stiffness determined from component properties .19
8.4.2 Flexural stiffness determined from material and geometric properties .19
8.4.3 Long term deflections .19
9 Axial load carrying members .19
9.1 General .19
© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO 22156:2021(E)
9.2 Compression member effective length.20
9.2.1 Lateral restraint of compression members .20
9.3 Compression capacity .21
9.3.1 Compression capacity from geometric and material properties .21
9.3.2 Crushing capacity .21
9.3.3 Buckling capacity . .22
9.4 Tension capacity .22
9.4.1 Tension capacity from component capacity .22
9.4.2 Tension capacity from geometric and material properties .23
9.5 Combined axial and flexural loads .23
10 Joints and splices .23
10.1 General .23
10.2 Design properties by complete joint testing .24
10.3 Design properties by component capacities .24
10.4 Allowable joint design capacity .24
10.5 Joint stiffness .25
10.6 Ductility of joints .25
10.7 Robustness against culm splitting .25
10.7.1 Radial clamping to resist splitting .26
10.8 Splices joints .26
10.9 Requirements for non-bamboo components of joints .26
10.9.1 Metallic components of joints .26
10.9.2 Joints utilising flowable infill material (grouted joints) .26
10.9.3 Lashing .27
10.9.4 Mechanical and proprietary joint systems .27
10.10 End bearing capacity of bamboo culms .27
10.11 Circumferential bearing capacity of bamboo culms .27
10.12 Joints having through culm wall dowels .29
10.12.1 Capacity of single dowel .29
10.12.2 Requirements for dowels .31
10.12.3 Tension forces on dowel joints .31
11 Trusses .31
12 Shear panels (walls) .32
12.1 General .32
12.1.1 Openings in panels .32
12.2 Loads . .33
12.2.1 Out-of-plane loads .33
12.2.2 In-plane loads .34
12.2.3 Gravity loads .35
12.3 Determination of design strengths .35
13 Fire resistance .36
14 Structural grading .36
15 Quality assessment and control.36
Annex A (informative) Bases of provisions in this document.37
Annex B (informative) Durability and preservation recommendations .38
Annex C (informative) Examples of seismic and alternative design factors .40
Annex D (informative) Examples and classification of bamboo connections and joints .41
Annex E (informative) Design of LCBF components to satisfy requirements of 12 .45
Bibliography .48
iv PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22156:2021(E)
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 165, Timber structures
This second edition cancels and replaces the first edition (ISO 22156:2004), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— adoption of design equations for material or component capacities for both members and joints;
— adoption of service classes and specific consideration of susceptibility to splitting;
— addition of Light Cement Bamboo Frame (LCBF) construction;
— addition of informative annexes addressing durability and representative details for connections
and LCBF construction;
— removal of use of bamboo for reinforcing concrete or soil.
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.
© ISO 2021 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
ISO 22156:2021(E)
Introduction
This document provides a means of structural design for one- and two-storey building structures using
full-culm round bamboo poles as the primary vertical and horizontal structural load resisting systems.
This document addresses connection design, light cement bamboo frame shear panel design, and
addresses issues of durability. Informative annexes provide means of achieving design and performance
goals in these areas.
vi PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 22156:2021(E)
Bamboo structures — Bamboo culms — Structural design
1 Scope
This document applies to the design of bamboo structures whose primary load bearing structure is made
of round bamboo or shear panel systems in which the framing members are made from round bamboo.
Except as indicated in Clause 12, this document applies to one- and two-storey residential, small
commercial or institutional and light industrial buildings not exceeding 7 m in height.
This document is concerned only with requirements for mechanical resistance, serviceability and
durability of bamboo structures.
This document permits an allowable load-bearing capacity design (ACD) and/or allowable stress design
(ASD) approach for the design of bamboo structures. Allowable load-bearing capacity and allowable
stress approaches may be used in combination in the same structure.
This document additionally recognises design approaches based on partial safety factor design (PSFD)
and/or load and resistance factor design (LRFD) methods (5.11.1), previous established experience
(5.11.2), or documented ‘design by testing’ approaches (5.11.3).
Other requirements, such as those concerning thermal or sound insulation, are not considered. Bamboo
structures may require consideration of additional requirements beyond the scope of this document.
Execution is covered to the extent that it impacts the quality of construction materials and products
required to comply with the design requirements contained herein.
This document provides a number of modification factors, designated C . These are empirically derived
i
factors, based on best available engineering judgement, that are believed to be universally applicable
to bamboo materials that are appropriate for building construction. Parameters affecting bamboo
material performance are many and are addressed explicitly through the use of experimentally
determined characteristic values of strength and stiffness. Annex A provides a summary of the bases
upon which the provisions of this document were developed.
This document does not apply to
— structures made of engineered bamboo products such as glue-laminated bamboo, cross-laminated
bamboo, oriented strand, or densified bamboo materials,
— bamboo-reinforced materials where bamboo is not the primary load-bearing constituent. This
includes bamboo-reinforced concrete, masonry and soil, or,
— scaffold structures constructed with bamboo.
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 12122-1, Timber structures — Determination of characteristic values — Part 1: Basic requirements
ISO 12122-5, Timber structures — Determination of characteristic values — Part 5: Mechanical connections
ISO 12122-6, Timber structures — Determination of characteristic values — Part 6: Large components
and assemblies
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 7 ----------------------
ISO 22156:2021(E)
ISO 16670, Timber structures — Joints made with mechanical fasteners — Quasi-static reversed-cyclic
test method
ISO 19624, Bamboo structures — Grading of bamboo culms — Basic principles and procedures
ISO 21581:2010, Timber structures - Static and cyclic lateral load test methods for shear walls
ISO 21887, Durability of wood and wood-based products — Use classes
ISO 22157, Bamboo structures — Determination of physical and mechanical properties of bamboo culms —
Test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
assembly
multiple-culm assembly
structural member comprised of more than one bamboo culm constructed in such a fashion that the
multiple culms together serve as a single structural member
3.2
bamboo culm
bamboo pole
single shoot of bamboo
Note 1 to entry: A culm is comprised of the entire unaltered bamboo cross section and is usually a hollow cylinder
except at nodes.
3.3
cross sectional area
A
area of the section perpendicular to the direction of the longitudinal axis of the culm
3.4
ductility
μ
ratio of the experimentally determined ultimate displacement to the yield displacement
1)
Note 1 to entry: The ratio is determined according to ISO/CD TR 21141 for joints.
3.5
equilibrium moisture content
w
EM
moisture content at which bamboo is neither gaining moisture from, nor losing moisture to, the
environment
3.6
fibre saturation point
w
FSP
moisture content below which only water bound in the cell walls remains; i.e., condition in which there
is no free water in the cell cavities
1) In preparation. Stage at the time of publication ISO/CD TR 21141:2021.
2 PROOF/ÉPREUVE © ISO 2021 – All rights reserved
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ISO 22156:2021(E)
3.7
flattened bamboo
element obtained by opening the bamboo culm and making longitudinal cuts (scores) partially through
the culm wall to make a flat member
Note 1 to entry: Flattened bamboo is often referred to as “esterilla”.
3.8
internode
typically hollow region of bamboo culm between two nodes
3.9
joint
connection of two or more bamboo members
3.10
lashing
means of connecting bamboo culms by continuous wrapping of material around culm and joint region
3.11
light cement bamboo frame
LCBF
improved vernacular construction technique originating in Latin America utilising shear walls
constituted from a cement mortar render applied onto strip, flattened or small diameter bamboo, which
are fixed onto bamboo and/or timber studs or framing
Note 1 to entry: The cement mortar render is reinforced by a small-gauge metal mesh such as “chicken wire”. An
alternative technique in which the cement mortar render is applied directly onto expanded metal lath sheets,
which are in turn fixed onto the frame, is also accepted. The system is also known as "bahareque encementado"
and composite bamboo shear walls.
3.12
moisture content
w
portion of culm weight consisting of water expressed as percentage of oven-dry weight
3.13
node
transverse diaphragm region located along length of culm separating adjacent internodes
3.14
non-redundant
structural member is non-redundant if there is no alternative and sufficient load path in the structure to
transmit the load carried by the member in the event of its removal (member failure) from the load path
Note 1 to entry: Failure of a non-redundant member leads to failure of the load path in which it is a part.
3.15
outer diameter
D
diameter of the cross section of a piece of bamboo, typically made near the centre of an internode, taken
as the average of two perpendicular measurements made across opposite points on the outer surface or
calculated from a measurement of the perimeter
3.16
point of contraflexure
point of inflection
location of zero moment where the curvature of the member is zero
© ISO 2021 – All rights reserved PROOF/ÉPREUVE 3
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ISO 22156:2021(E)
3.17
shear span
distance between the maximum moment and the nearest point of c
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