ISO 23478:2022
(Main)Bamboo structures — Engineered bamboo products — Test methods for determination of physical and mechanical properties
Bamboo structures — Engineered bamboo products — Test methods for determination of physical and mechanical properties
This document specifies test methods suitable for determining the following mechanical properties of engineered bamboo products: a) modulus of elasticity in bending; b) shear modulus; c) bending strength; d) modulus of elasticity in tension parallel to the fibre; e) tension strength parallel to the fibre; f) modulus of elasticity in compression parallel to the fibre; g) compression strength parallel to the fibre; h) modulus of elasticity in tension perpendicular to the fibre; i) tension strength perpendicular to the fibre; j) modulus of elasticity in compression perpendicular to the fibre; k) compression strength perpendicular to the fibre and shear strength; i) shear strength parallel to the fibre. In addition, the determination of dimensions, moisture content and density are specified. This document is applicable to prismatic shapes of glued laminated bamboo and bamboo scrimber intended to resist flexure, shear, axial loads, or combinations thereof.
Structures en bambou — Produits en bambou reconstitués — Méthodes d’essai pour la détermination des propriétés physiques et mécaniques
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 23478
First edition
2022-06
Bamboo structures — Engineered
bamboo products — Test methods
for determination of physical and
mechanical properties
Structures en bambou — Produits en bambou reconstitués —
Méthodes d’essai pour la détermination des propriétés physiques et
mécaniques
Reference number
ISO 23478:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 23478:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 23478:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
4.1 Symbols . 3
5 Determination of dimensions of test specimens . 5
6 Determination of moisture content of test specimens . 5
6.1 Moisture content by oven-dry method . 5
6.1.1 Apparatus . 5
6.1.2 Preparation of test pieces . 5
6.1.3 Procedure . 5
6.1.4 Calculation and expression of results. 6
6.2 Moisture content by electrical moisture meter method . 6
6.2.1 General . 6
6.2.2 Apparatus . 6
6.2.3 Procedure . 6
6.2.4 Calculation and expression of results. 6
6.3 Test report . 7
7 Determination of density of test specimens . 7
7.1 General . 7
7.2 Apparatus . 7
7.3 Preparation of test pieces . 7
7.4 Procedure . 7
7.5 Calculations and expression of results . 7
7.6 Test report . 8
8 Conditioning of test specimens . 8
9 Determination of local (shear-free) modulus of elasticity in bending .8
9.1 Test specimen . 8
9.2 Procedure . 8
9.3 Expression of results . . 9
10 Determination of global modulus of elasticity in bending.10
10.1 Test specimen . 10
10.2 Procedure . 10
10.3 Expression of results . . 11
11 Determination of shear modulus — Variable span method .12
11.1 General .12
11.2 Test piece .12
11.3 Procedure .12
11.4 Expression of results . 13
11.4.1 Determination of K .13
1
11.4.2 Shear modulus . 13
12 Determination of bending strength .14
12.1 Test specimen . 14
12.2 Procedure . 14
12.3 Expression of results . 15
13 Determination of the strength and modulus of elasticity in tension parallel to the
fibre .15
13.1 General . 15
iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 23478:2022(E)
13.2 Test specimen . 15
13.3 Procedure . 16
13.4 Expression of modulus results . 17
13.5 Expression of strength results . 17
14 Determination of the strength and modulus of elasticity in compression parallel to
the fibre of the engineered bamboo product .17
14.1 General . 17
14.2 Test specimen . 18
14.3 Procedure . 18
14.4 Expression of modulus results . 18
14.5 Expression of results . . 18
15 Determination of the strength and modulus of elasticity in compression and
tension perpendicular to the fibre of the engineered bamboo product .19
15.1 Requirements for test specimens . 19
15.2 Procedure . 19
15.3 Expression of results . 21
15.3.1 Compression strength perpendicular to the fibre . 21
15.3.2 Compression modulus perpendicular to the fibre .22
15.3.3 Tension strength perpendicular to the fibre .23
15.3.4 Tension modulus perpendicular to the fibre . 23
16 Determination of shear strength parallel to the fibre .24
16.1 Requirements for test specimens . 24
16.1.1 Fabrication . 24
16.2 Procedure . 26
16.3 Expression of results . 26
17 Test report .26
17.1 General . 26
17.2 Test specimen . 26
17.3 Test method . 27
17.4 Test results . 27
Bibliography .28
iv
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 23478:2022(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 on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 165, Timber structures.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 23478:2022(E)
Bamboo structures — Engineered bamboo products — Test
methods for determination of physical and mechanical
properties
1 Scope
This document specifies test methods suitable for determining the following mechanical properties of
engineered bamboo products:
a) modulus of elasticity in bending;
b) shear modulus;
c) bending strength;
d) modulus of elasticity in tension parallel to the fibre;
e) tension strength parallel to the fibre;
f) modulus of elasticity in compression parallel to the fibre;
g) compression strength parallel to the fibre;
h) modulus of elasticity in tension perpendicular to the fibre;
i) tension strength perpendicular to the fibre;
j) modulus of elasticity in compression perpendicular to the fibre;
k) compression strength perpendicular to the fibre and shear strength;
i) shear strength parallel to the fibre.
In addition, the determination of dimensions, moisture content and density are specified.
This document is applicable to prismatic shapes of glued laminated bamboo and bamboo scrimber
intended to resist flexure, shear, axial loads, or combinations thereof.
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 22157, Bamboo structures — Determination of physical and mechanical properties of bamboo culms
— Test methods
ISO 21625, Vocabulary related to bamboo and bamboo products
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 22157, ISO 21625 and the
following apply.
1
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 23478:2022(E)
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
bamboo scrimber
panel or structural member made of compressed bamboo fibre bundle strips or compressed bamboo
fibre bundle sheet
[SOURCE: ISO 21625:2020, 3.2.17]
Key
1 width, b
2 depth, h
indicates parallel to fibre orientation
Figure 1 — Example of bamboo scrimber
3.2
bamboo strip
bamboo piece with outer and inner layers intact, made by cutting bamboo culm in longitudinal direction
3.3
bamboo lamina
thin and flat bamboo piece with rectangular cross-section, processed from bamboo strip (3.2) by
removing the outer and inner layers of the bamboo culm wall
3.4
engineered bamboo member
assembly of individual elements made of bamboo
3.5
glued laminated bamboo
structural member formed by bonding together bamboo strips (3.2) with their fibres running essentially
parallel
[SOURCE: ISO 21625:2020, 3.3.1.14]
2
© ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 23478:2022(E)
3.6
non-structural joint
non-structural connection (e.g. butt, hook joint) to support manufacturing process and is not designed
to transfer stress across the connection
3.7
traveller specimen
specimen identical to, and stored and conditioned identically to specimens to be tested used to obtain
properties whose testing method affects the specimen
Note 1 to entry: Traveller specimens are usually used for determination of moisture content and density.
[SOURCE: ISO 22157:2019, 3.12]
a) Horizontal board orientation b) Vertical board orientation
Key
b width, b
h depth, h
1 bamboo lamina
indicates parallel to fibre orientation
Figure 2 — Example of glued laminated bamboo
4 Symbols
4.1 Symbols
A cross-sectional area, in square millimetres;
a distance between a loading position and the nearest support in a bending test, in millimetres;
b width of cross-section in a bending test, or the smaller dimension of the cross-section, in
millimetres;
3
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 23478:2022(E)
E modulus of elasticity in compression parallel to the fibre, in Newton per square millimetre;
c,0
E modulus of elasticity in compression perpendicular to the fibre, in Newton per square mil-
c,90
limetre;
E global modulus of elasticity in bending, in Newton per square millimetre;
m,g
E apparent modulus of elasticity in bending, in Newton per square millimetre;
m,app
E modulus of elasticity in tension parallel to the fibre, in Newton per square millimetre;
t,0
E modulus of elasticity in tension perpendicular to the fibre, in Newton per square millimetre;
t,90
F load, in Newtons;
F maximum compressive load perpendicular to the fibre, in Newtons;
c,90,max
F estimated maximum compressive load perpendicular to the fibre, in Newtons;
c,90,max,est
F maximum load, in Newtons;
max
F estimated maximum load, in Newtons;
max,est
F maximum tensile load perpendicular to the fibre, in Newtons;
t,90,max
F yield load, in Newtons;
y
F maximum (ultimate) load applied in test, in Netwons;
ult
f compressive strength parallel to the fibre, in Newton per square millimetre;
c,0
f compressive strength perpendicular to the fibre, in Newton per square millimetre;
c,90
f bending strength, in Newton per square millimetre;
m
f tensile strength parallel to the fibre, in Newton per square millimetre;
t,0
f tensile strength perpendicular to the fibre, in Newton per square millimetre;
t,90
G shear modulus, in Newton per square millimetre;
h depth of cross-section in a bending test, or the larger dimension of the cross-section, in
millimetres;
h gauge length, in millimetres;
0
h test specimen height in perpendicular to fibre tests, in millimetres;
t
I second moment of area, in millimetres to the fourth power;
l span in bending, or length of test specimen between the testing machine grips in compression
and tension, in millimetres;
l gauge length for the determination of modulus of elasticity or shear modulus, in millimetres;
1
m mass of the test piece before drying, in grams;
e
m initial mass before drying, in grams;
i
m final oven-dry mass, in grams;
0
4
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 23478:2022(E)
S section modulus, in millimetres to the third power;
V volume of the test piece, in millimetres to the third power;
V volume of the test piece in the absolutely dry condition, in millimetres to the third power;
0
w moisture content;
Δ displacement, in millimetres;
δ
change in slope;
ρ density under conditions of test, in grams per millimetre to the third power;
test
ρ dry density, in grams per millimetre to the third power.
0
5 Determination of dimensions of test specimens
The dimensions of the test specimen shall be measured to a precision of 1 % of the least cross-sectional
dimensions of the member. All measurements shall be made when the test specimens are conditioned as
specified in Clause 8. If the width or thickness varies within a test specimen, these dimensions should
be recorded as the average of three separate measurements taken at different positions on the length of
each specimen.
6 Determination of moisture content of test specimens
6.1 Moisture content by oven-dry method
6.1.1 Apparatus
6.1.1.1 Balance, suitable to weigh a specimen with a precision of at least 0,5 % of the specimen mass.
6.1.1.2 Oven, capable of drying specimen to the absolute dry condition.
6.1.2 Preparation of test pieces
Specimens for determination of moisture content shall be prepared immediately after each mechanical
test. The number of specimens shall be equal to the number of test pieces for the physical or mechanical
test. If traveller specimens are used, these shall be prepared immediately after each mechanical test,
and placed in the drying oven.
The moisture content of the test specimen shall be determined on a section taken from the test
specimen. For engineered bamboo products the section shall be of full cross-section. For perpendicular
to fibre test specimens the moisture content shall be determined from the whole specimen.
In strength tests for bending, shear, tension parallel and perpendicular to fibre and compression
parallel and perpendicular to fibre, the moisture content of the test specimen shall be determined near
the place of failure.
6.1.3 Procedure
The test pieces shall be weighed with a precision of at least 0,5 % of the dry specimen mass prior to
being placed in an oven at a temperature of (103 ± 2) °C. The initial mass is m .
i
After 24 h, the mass shall be recorded at regular intervals of not less than 2 h. The drying shall be
considered to be complete when the difference between successive determinations of mass does not
exceed 0,5 % of the measured mass. The final oven-dry mass is m .
0
5
© ISO 2022 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 23478:2022(E)
The following modifications for bamboo scrimber shall be made. After 48 h, the mass shall be recorded
at regular intervals of not less than 6 h. The drying shall be considered to be complete when the
difference between successive determinations of mass do not exceed 0,1 % of the measured mass. The
final oven-dry mass is m .
0
6.1.4 Calculation and expression of results
The moisture content, w, of each test piece shall be calculated with Formula (1) as the loss in mass,
expressed as a percentage of the oven-dry mass:
mm−
i0
w = ×100 (1)
m
0
where
m is the initial mass of the test piece before drying;
i
m is the oven-mass of the test piece.
0
Both m and m are measured with a precision of at least 0,5 % of the dry specimen mass for laminated
i 0
bamboo and of at least 0,1 % of the dry specimen mass for bamboo scrimber.
The calculated value of w shall be taken as representative of the test specimen as a whole.
6.2 Moisture content by electrical moisture meter method
6.2.1 General
Alternatively, it can be sufficiently accurate to measure moisture content by means of a moisture meter,
provided that the meter is calibrated against moisture content measurements using the oven-dry
method described in 6.1. Commercial conductivity moisture meters are generally only reliable for wood
moisture content between about 5 % and 30 %.
6.2.2 Apparatus
6.2.2.1 Moisture meter, of any design calibrated for laminated bamboo and bamboo scrimber (using
the oven-dry method described in 6.1), and capable of making an individual measurement with an error
of not more than 2 % at moisture contents from 7 % to 30 %.
6.2.3 Procedure
Measure the moisture content of the test piece or traveller specimen at a location within the specimen.
Measurements should be taken either at freshly cut cross-sections, or by driving deep, sharp probes
into the specimen.
The area at which measurements are made shall not contain any contaminants or visible defects. Drive
the electrodes into the cross-section so that the line between the tips of the needles intersects the
specimen.
Make at least three measurements in each measuring area, 10 mm to 15 mm apart, to avoid any error
due to the electrodes piercing an invisible defect.
6.2.4 Calculation and expression of results
Calculate t
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.