ISO 22156:2004

Bamboo — Structural design

ISO 22156:2004 applies to the use of bamboo structures, i.e. structures made of bamboo (round bamboo, split bamboo, glued laminated bamboo) or bamboo-based panels joined together with adhesives or mechanical fasteners. ISO 22156:2004 is based on limit-state design, and on the performance of the structure. It is only concerned with the requirements for mechanical resistance, serviceability and durability of structures.

Bambou — Conception des structures

General Information

• Status: Withdrawn
• Publication Date: 13-May-2004
• Withdrawal Date: 13-May-2004
• ICS: 91.080.20 - Timber structures
• Technical Committee: ISO/TC 165 - Timber structures
• Drafting Committee: ISO/TC 165 - Timber structures
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 03-Jun-2021

Relations

• Revised: ISO 22156:2021 - Bamboo structures — Bamboo culms — Structural design
• Effective Date: 27-May-2017

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22156
First edition
2004-05-15
Bamboo — Structural design
Bambou — Conception des structures

Reference number
ISO 22156:2004(E)
©
ISO 2004

---------------------- Page: 1 ----------------------
ISO 22156:2004(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall
not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the
unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
©
ii ISO 2004 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 22156:2004(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Basic requirements . 2
6 Design concepts . 3
7 Structural design . 4
8 Schematisation . 6
9 Beams (predominantly loaded in bending) . 6
10 Columns (predominantly loaded in an axial direction) . 7
11 Joints . 7
12 Assemblies (trusses) . 9
13 Panels . 10
14 Reinforcement in concrete and soil . 11
15 Durability and preservation . 11
16 Fire protection . 11
17 Grading . 12
18 Quality control . 12
Annex A (informative) Background and history . 14
Annex B (informative) Assumptions . 15
©
ISO 2004 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 22156:2004(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.
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 22156 was prepared by Technical Committee ISO/TC 165, Timber structures.
©
iv ISO 2004 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 22156:2004(E)
Bamboo — Structural design
1Scope
This International Standard applies to the use of bamboo structures, i.e. structures made of bamboo (round
bamboo, split bamboo, glued laminated bamboo) or bamboo-based panels joined together with adhesives or
mechanical fasteners.
This International Standard is based on limit-state design, and on the performance of the structure; see also
7.1. It is only concerned with the requirements for mechanical resistance, serviceability and durability of
structures.
Other requirements, e.g. concerning thermal or sound insulation, are not considered. Bamboo used as a
composite structure may require additional considerations beyond this International Standard. Execution (work
on-site, and fabrication of components off-site, and their erection on-site) is covered to the extent that is
necessary to indicate the quality of construction materials and products which should be used and the standard
of workmanship on-site needed to comply with the assumptions of the design rules.
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 6891, Timber structures — Joints made with mechanical fasteners — General principles for the
determination of strength and deformation characteristics
ISO 16670, Timber structures — Joints made with mechanical fasteners — Quasi-static reversed-cyclic test
method
ISO 22157-1, Bamboo — Determination of physical and mechanical properties — Part 1: Requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
joint
connection between two or more bamboo structural elements
3.2
node
place in a bamboo culm where branches sprout and where a diaphragm is inside the culm
©
ISO 2004 – All rights reserved 1

---------------------- Page: 5 ----------------------
ISO 22156:2004(E)
4 Symbols and abbreviated terms
2
σ the allowable stress, in N/mm
all
4
I the second moment of area, in mm
B
5 Basic requirements
5.1 General
A structure shall be designed and constructed in such a way that
— with acceptable probability, it will remain fit for the use for which it is required, having due regard to its
intended life and costs, and
— with appropriate degrees of reliability, it will sustain all actions and influences likely to occur during execution
and use and have adequate durability in relation to maintenance costs.
NOTE See also informative Annex B.
5.2 Exceptional events
A structure shall also be designed in such a way that it will not be damaged by events like explosions, impact or
consequences of human errors, to an extent disproportionate to the original cause.
5.3 Potential damage
The potential damage should be limited or avoided by the appropriate choice of one or more of the following:
— avoiding, eliminating or reducing the hazards which the structure is to sustain;
— selecting a structural form that has low sensitivity to the hazards considered;
— selecting a structural form and design that can survive adequately the accidental removal of an individual
element;
— selecting a structural form and design which provides sufficient continuity between individual elements.
5.4 Choice of materials
The above requirements shall be met by the choice of suitable materials, by appropriate design and detailing
and by specifying control procedures for production, construction and use as relevant for the particular project.
5.5 Exception
All bamboo constructions shall comply with this International Standard completely; as an exception,
constructions complying only with 6.2.2 and/or 6.2.3 are deemed to comply with the requirements of this
standard.
The purpose of this exception is that building processes in the informal sector need a long period of teaching
and training in order to support self-help building to the full, and also to promote the self-reliance of lower
income groups. National Building Codes should specify step-wise processes starting from zero, until the said
assumptions can be reached in the future.
©
2 ISO 2004 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 22156:2004(E)
6 Design concepts
6.1 Concepts based on calculations
Bamboo construction design concepts shall be based on calculations, verifying that no relevant limit state or no
relevant permissible stress is exceeded (see Clause 7), except as noted in 6.2.
6.2 Concepts based otherwise
6.2.1 General
Bamboo construction design concepts are deemed to comply, provided the concepts are based on one of the
items in 6.2.2 or 6.2.3.
6.2.2 Experience from previous generations
Experience from previous generations is well preserved in local traditions, and carefully transmitted to people
living today. This expertise can be considered as an informal, non-codified “standard”.
Criteria for reliability are:
— the content shall be generally known and accepted;
— it shall be considered as an old and pure tradition, as general wisdom;
— the community shall be characterised by an undisturbed social structure, with a well-recognised social
pattern.
Limitations are:
— the content is only applicable in similar situations;
— after migration, the presence of this tradition is no longer self-evident.
6.2.3 Reports on evaluations
These reports are based on evaluations made after disasters like earthquakes and hurricanes. If these reports
contain descriptions cf structures which did survive a quantitatively described disaster, similar structures shall
be considered as adequate for similar disasters in the future.
Criteria for the reliability are:
— the report shall be written by acknowledged engineers, with adequate experience in the field;
— the report shall be accepted by the international technical community and/or proven by referees;
— the report shall provide full details and full information, with which one can build similar structures.
Limitations are:
— the report is only applicable in similar situations.
6.3 Alternative design
It is permissible to use alternative design rules which differ from this International Standard, provided that it is
shown that the alternative rules comply with relevant principles and are at least equivalent with regard to the
strength, serviceability and durability achieved for the structure with this International Standard.
©
ISO 2004 – All rights reserved 3

---------------------- Page: 7 ----------------------
ISO 22156:2004(E)
7 Structural design
7.1 Limit states
NOTE For allowable stress design, see 7.4.
Limit states are states beyond which the structure no longer satisfies the design performance requirements.
Limit states are classified into ultimate limit states, and serviceability limit states.
Ultimate limit states are those associated with collapse, or with other forms of structural failure which may
endanger the safety of people. States prior to structural collapse which, for simplicity, are considered in place of
the collapse itself, are also classified and treated as ultimate limit states. Ultimate limit states, which may require
consideration, include
— loss of equilibrium of the structure or any part of it, and
— failure by excessive deformation or excessive forces, causing rupture or loss of stability of the structure or of
any part of it, including supports and foundations.
Serviceability limit states correspond to states beyond which specified service criteria are no longer met.
Serviceability limit states, which may require consideration, include
— deformations or deflections which affect the appearance or effective use of the structure (including the
malfunction of machines or services) or cause damage to finishes or non-structural elements, and
— vibration which causes discomfort to people, damage to the building or its contents, or which limits its
functional effectiveness.
7.2 Material properties
7.2.1 Characteristic value
A material property is represented by a 5 percentile property, estimated from test results, obtained as in
ISO 22157-1, with 75 % confidence that it represents the population. This is called the characteristic value. It
can be obtained with this formula:
� �
s
2,7
m
R =R 1− √
k 0,05
n
where
R is the characteristic value;
k
R is the 5 percentile from the test data;
0,05
m is the mean value from the test data;
s is the standard deviation from the test data;
n is the number of tests (at least 10).
7.2.2 Design stresses
For the derivation of design stresses from the characteristic value, the following rules shall be applied.
Strength and stiffness parameters shall be determined on the basis of tests for the types of action effects to
which the material will be subjected in the structure, or on the basis of comparisons with similar bamboo
species or bamboo-based materials or on well-established relations between the different properties.
©
4 ISO 2004 – All rights reserved

---------------------- Page: 8 ----------------------
ISO 22156:2004(E)
It shall be shown that the dimensional stability and environmental behaviour are satisfactory for the intended
purposes.
Special attention shall be given to differences between material originating from different localities.
Since the characteristic values are determined on the assumption of a linear relation between stress and strain
until failure, the strength verification of individual members shall also be based on such a linear relation.
The structural behaviour shall generally be assessed by calculating the action effects with a linear material
model (elastic behaviour).
Service classes shall be defined according to the temperatures and relative humidity occurring in the regions.
Design stresses shall be determined in a similar way as for timber structures.
7.3 Design requirements
It shall be verified that no relevant limit state is exceeded. All relevant design situations and load cases shall be
considered. Possible deviations from the assumed directions or positions of actions shall be considered.
Calculations shall be performed using appropriate design models (supplemented, if necessary, by tests)
involving all relevant variables. The models shall be sufficiently precise to predict the structural behaviour,
commensurate with the standard of workmanship (of the labour force) likely to be achieved, and with the
reliability of the information on which the design is based.
The verification of limit states, and the partial safety factors, shall be in accordance with relevant National
Standards.
The loads and actions, to be considered in the calculations, shall be in accordance with relevant National
Standards.
7.4 Allowable stresses
Instead of the limit-state design procedure, allowable stress design can be adopted. Allowable stresses can be
derived from test results with the following formula:
D
σ =R ×G×
all k
S
where
2
σ is the allowable stress, in N/mm ;
all
R is the characteristic value;
k
G is the modification for the difference between laboratory quality and practice; default value 0,5;
D is the modification value for duration of load:
— 1,0 for permanent load,
— 1,25 for permanent plus temporary load,
— 1,5 for the above plus wind-load;
S is the factor of safety, default value 2,25.
NOTE With a standard deviation of 15 % and for a permanent load, the allowable stress is about 1/7 of the mean ultimate
strength.
©
ISO 2004 – All rights reserved 5

---------------------- Page: 9 ----------------------
ISO 22156:2004(E)
7.5 Sound construction practices
The designer shall ensure that sound construction practices are taken into account, according to this subclause.
The use of air-dry bamboo, and of details which ensure that bamboo in buildings shall remain air-dry, and which
ensure that bamboo, once it has become wet, shall have the opportunity to dry again before the material can
deteriorate due to the moisture content. (For durability and preservation, see Clause 15.)
The permeability of walls, floors and roofs made from bamboo, causing internal pressures, which change the
net wind-load acting on the roof, wall and floor.
Special attention shall be given to check whether the workmanship of the labour force, in the factory and on the
building site, is according to the assumptions.
Other similar relevant items.
8 Schematisation
This is the process of “translating” the physical reality of a building structure towards a schematised system of
symbols to be used during the calculation process. The schematisation is based on the theory of applied
mechanics. Typically, bamboo schematisation involves the following assumptions.
The elastic behaviour of bamboo, until failure; as the plastic behaviour is considered to be not significant.
Bamboo culms are analysed as hollow-tube structures with variable thickness.
Bamboo culms are analysed as not perfectly straight members.
Bamboo culms are analysed as tapered.
Nodes do not occur at constant intervals, which is a problem in practice because joints or supports are
preferably located near nodes.
Conventional structural-analysis methods are used with definitions of the initial curvature, the diameter and the
wall thickness.
Any bamboo joint or support shall be considered to act as a hinge, unless substantiating data are submitted to
justify a spring or a fixed joint.
Bernoulli's theorem (flat cross-sections remain flat) is valid for bamboo.
9 Beams (predominantly loaded in bending)
The design of beams shall be based on calculation. Calculation shall be based on the following items, provided
the load is symmetrical. For asymmetrical loads, applied stresses at critical points shall be calculated.
The second moment of area I shall be determined as follows.
B
— The outside diameter and the wall thickness shall be measured at both ends, in accordance with
ISO 22157-1.
— With these values, the mean diameter and the mean wall thickness for the middle of the beam shall be
calculated.
I
— The second moment of area shall be calculated with these mean values for diameter and wall thickness.
B
NOTE This method is on the conservative side. Another method is to calculate the I at both ends and take the mean value
B
of these two I s; this gives a bigger value. Therefore, this calculation is not applied in this standard.
B
©
6 ISO 2004 – All rights reserved

---------------------- Page: 10 ----------------
...