Non Destructive Test For Grading Of Bamboo Poles For Structural Use
Ramesh Chaturvedia aProfessor (retired) Indian Institute of Technology Mumbai India
Key words Non-destructive test, Grading, Bamboo poles, Structural use, Test metric (E*I)
Abstract:
This paper presents an attempt, at conception followed by complete design and development of
a set up, that could non destructively, determine a characteristic of a given bamboo pole, that is
a measure of its strength and stiffness properties, and thus provide an assurance of quality for
it’s application in structures. Limitations of the existing IS 6874 and ISO22157 in this regard
are discussed while arriving at a suitable metric (E*I) and the method for it’s determination.
Details of the test setup developed are described along with test results. The concept of treating
Bamboo as a Product rather than a material is another innovation that justifies this method of
testing. A modified design process that is based on the capacity of members to withstand
specified forces, rather than that of the material to sustain stresses has been suggested and
illustrated using the design of a purlin by way of example. The test metric namely (E*I) is
shown to be adequate for design and the test setup is simple, rugged, cheap, effective and fully
functional. However, some extended test runs under field conditions shall be useful to identify
and correct operational problems. The design process need to be extended to other members
such as columns and trusses etc to make it more widely applicable, and to identify other
measures of property of bamboo poles that may be relevant and later to develop the appropriate
test procedures and set ups .
1 Introduction
Bamboo is a Vegetal Rod. Dunkelburg (1) avers that logically Vegetal Rods would have
been the prime components of structures used in the construction of shelters for Human and
Domesticated animals right after the times of the Cave Man. Use of stone and earth may have
been developed concurrently or a little later. However these were the privileges of some of the
mightiest of kings and emperors of that time. Remnants of stone shelters of that time are all that
remain today, while there are few traces of those made of bamboo or earth even though they
sheltered the masses. The advent of bricks, cement concrete, steel, reinforced concrete and sawn
timber (lumber) has all but driven out earth and vegetal rods from structures in urban areas all
over the world, and a fair bit of rural areas except in the poorer countries. Such structures are
vanishing even from there. Few of the Engineering College text books mention them as
materials of construction, the applicable techniques are seldom referred to even in schools
training artisans, and the design methodologies are not part of Engineering Curricula. The
current building codes also do not generally include them as approved materials of construction
and if they do, lay down specifications that are more of a bar rather than an enabler. Little
wonder that even the poor who have used them for generations, now prefer the brick/concrete
for their abodes if they are able to afford the cost.
Though bamboo provides a much greener, cleaner and sustainable alternative to the
modern age materials used in shelters, it requires considerable effort on the part of the research
community well supported by bodies such as INBAR and advocates of a Greener Planet, to
come up with solutions that overcome the negative perceptions. This paper is an attempt to
address the problem of quality assurance.
2 Standards for determination of properties and design of structures.
IS 6874 -1973 (2) was one of the earliest national specification of the method of tests for
Round bamboo. It has been revised in 2008 to bring it in line with ISO 22157-2004 (3). ISO
22156 (4) lays down the specifications for Bamboo Structural Design. These standards, are
similar in structure and content, with the corresponding standards applicable to the more
commonly used materials such as concrete, RCC, and steel. Thus Bamboo Structures that are in
conformity with the above ISOs should be as acceptable as structures in other more commonly
used materials. This should have led to increasing use of bamboo in structures but unfortunately
it has not. Perhaps the reasons can be traced back to the contents of these Standards.
ISO 22156 (4), Bamboo Structural Design, is a rather long document (18 sections, as
many pages) and mostly non specific (just 2 equations). Aiming to match the requirements on
Structural design with more common materials in the details, it virtually shuts out simple
designs by small time individual designers and has restricted growth. Similarly ISO 22157
specifies the method of testing for physical and mechanical properties on the same lines as for
the common materials, and has been providing guidance along the (long and tortuous) path, of
generating and documenting mechanical property data for the numerous (hundreds) species of
bamboo, so that they could be considered for use in structures meeting the standards of ISO
certification, an objective that remains a distant dream.
These standards are expected to lead to generation of a reliable data base of mechanical
properties such as the Elastic Modulus, the values of limit stresses in different stress states such
tension, compression, shear, and bending to form the basis of design. Considerable work has
been done in this direction but the in-effectiveness of the end result can be gauged by observing
table 2 (Safe Working Stresses of Bamboo) in the National Building Code of India, section 3B
Bamboo of Part 6 that deals with Structural Design (5). It specifies (Table2) the safe working
stresses in bending (8.3-20.9 MPa) and compression (10.1-15.4 MPa) as well as the Modulus of
Elasticity(0.64-3.28 GPa) for 16 different species of Bamboo that it approves for structural use.
The specifications in Clause 5 for permissible stresses are rather difficult to interpret. To use
such a guide the designer must be sure of the specie to be used before he ventures on the design.
Designing with conventional materials he has no such problem.
As mentioned earlier courses in design at engineering institutions, and related text books
do not include designing with bamboo. One has to search through special literature such as
Journals, Conference proceedings, special reports, to gain some insight. An attempt by the
Author in this direction revealed that:
• Literature is mostly qualitative
• Designs are mostly done by Architects concentrating on Form rather than structural
performance
• Designs by Bhalla [6] & that on Scaffolding [7], that are analytical, have designs treating
Bamboo Culms as Tubes of constant thickness, and diameter
• Other Texts eg Gutierrez (Inbar TR 19)[8]) & Janssen (Inbar TR 20),[9]) have hardly any
equations for quantitative considerations in design
3 Grading based on Mechanical Properties
The importance of GRADING based on mechanical properties has always been well
recognized. Section 17 of the ISO 22156 [4], Bamboo Structural Design is titled GRADING
and is reproduced below
17.1 Bamboo shall be graded in accordance with approved rules ensuring that
the properties of the bamboo are satisfactory for use, and especially that the strength
and stiffness properties are reliable
17.2 The grading rules shall be based on a visual assessment of bamboo, on
non-destructive measurement of one or more properties, or on a combination of two
methods
17.3 special attention to age, the taper of the culm, the straightness, the
internodal length, and the distribution of nodes
Clause 4.4 of the National Building Code of India Part 6, Section 3b ( 5) deals with
Grading of Structural Bamboo and defines Grading as sorting out bamboo on the basis of
characteristics important for structural utilization as under:
a Diameter and length of culm
b Taper of culm
c Straightness of culm
d internodal length
e Wall thickness
f Density and strength
g Durability and seasoning
One of the above characteristics or sometimes combination of 2 or 3 characteristics form
the basis of grading. The culms shall be segregated species-wise.
It further explains the procedure in subsequent clauses for each of the characteristic. For
diameter it suggests 3 different grades based on its value (each with a fairly wide range) and sub
grades in steps of 10 mm but for length it specifies a minimum preferable value of 6m. For taper
and curvature (straightness), it specifies a maximum permissible value and for wall thickness a
minimum.
Explanations for internodal length, density and strength, and durability and seasoning
are not included, but exclusion of culms with certain visible defects, and other characteristics
e.g. immature, is suggested. Finally it suggests the use of bamboo of at least 4 years of age.
Read with ISO 22156 the above explanation serves the purpose of defining the approved
rules that has been left undefined in Clause 17.1.
While the list of characteristics includes, reliability of strength and stiffness property in
ISO and strength in the Building Code they have been left vague as there are no methods for
Non Destructive Tests for strength/stiffness in existing standards. This gap has been recognized
and there have been a few attempts at development of NDT that could be indicative of strength
and so could form a basis of grading.
Cheng-Jung Lin · Ming-Jer Tsai · Song-Yung Wang [10] has used the measurement of
drilling resistance as a predictor for density, and the measurement of velocity of transmission of
an ultrasonic signal and density, to predict the value of Elastic Modulus. The value of Elastic
Modulus, and the MOR were also determined using a static bend test and the same were
compared with predicted values for a few specimens. There was a positive correlation
(suggesting that these NDT methods could be used). However the coefficient of determination
values were rather low indicating that the predictions may have significant errors. Suneet Tuli
etal [11] have shown that thermal wave imaging can be used to detect sub surface defects in
Bamboo and could be a good NDT test to remove defective pieces during grading
The Gap is recognized by others as well as Trujillo [12], had emphasized on it while
presenting his research proposal “Prospects for a method to infer non-destructively the strength
of bamboo”. INBAR has funded a project at the University of Coventry U.K. The two authors
(Trujillo & Chaturvedi) were however unaware of each other’s work till they were brought
together in Oct/Nov. 2013, by INBAR for submission of a proposal for the GII grant [13].
4 Innovations in Concepts
This author received his first introduction to the area of tests on bamboo only in 2010,
when he was invited by Prof. Sudhakar the Principal Investigator at IIT Delhi of the subproject
“Bamboo as a Green Engineering Material in Rural Housing and Agricultural Structures for
Sustainable Economic Growth “ of the National Agricultural Innovation Project of India [14] .
One of the 5 objectives (No1) was “Study of the rheological properties of Bamboo (Indian
Species) in different agro climatic conditions “[15]. As they had envisaged (based ! on ISO
22157) “close to 10000 tests on just 2 out of 115 species that are common in India” they were
working on developing a machine to test bamboo. Being relatively a novice in this area this
author could think a bit different and so considered the possibility of bypassing ISO 22157 and
came up with a few novel concepts listed below:
Concept 1 Bamboo Poles are a Product (of nature). Since they are not Material ISO
22157, that specifies the method of testing for evaluation material properties may not be used
Concept 2 When we are using Bamboo Poles in Structures, we are using a product.
Since ISO 22156 does not cover this case, it is also not applicable
These concepts lead to the conclusion that it is possible to consider Properties other than
those listed in ISO 22157. For different members of structures we may need to define a different
set of properties of the pole that are relevant to the ability of the pole to perform the function
(ability to withstand forces, moments etc) without failure.
5 New metrics
Author suggested the use of the metric , Product of Elastic Modulus and Moment of
Inertia (E*I) of the individual pole privately to Prof. Sudhakar of Indian Institute of Technology
Delhi and Nripal Adhikari of INBAR . The later supported the concept and was instrumental in
securing a consultation contract for the author to work on the design and development of the
New Concept Test methods and Set ups. The concept was later shared with a wider audience
[16]
There are several advantages in considering this as a good metric namely:
1 The metric relates rather closely to two important parameters in the design of
members of structures viz.:
a Deflection of beams
b Eulers Buckling load for Column
2 The property can be directly and quickly determined through a Non Destructive Test
3 This provides a more reliable estimate of the property for application in design
compared to that obtained through tests for determination of E, and the method of estimating the
value of I as specified in ISO 22157.
Further consideration of the design process of beams led to inclusion of Safe Bending
Moment, and Safe Shear Force in this new list of Metrics. Inclusion of other metrics is
envisaged as the design process is developed. However the emphasis is on inclusion of those
that can be measured using non destructive tests
6 Development of Equipment and Procedure
6.1 Test Equipment: Since the development of test method and equipment was not
constrained by any standards, simplicity, low cost, and suitability for field use were added as
additional parameters besides the usual considerations of adequate accuracy and reliability of
measurements. Bending test was the obvious choice, as E*I could be determined from the
observations of loads and deflection. The test equipment and process specified in ISO 22157
was starting point. It specifies the 4 point test to ensure that the test is under pure bending. Since
this was no longer a consideration the 3 point bending test is a better choice based on simplicity.
A fixed span set up was envisaged for reasons that shall become evident later
6.1.1 4m Test Set Up: ISO 22157 specifies the minimum length of specimen as 30*D
+ atleast half internode length, while IS 6874 specifies minimum at 30*D+ 1m. We expected
the maximum diameter of bamboo to be about 100 mm and so the initial concept was for a
length of about 4m. The set up is shown in Fig1.
Test Setup for 4m NCBT
Figure 1
It consists of two Platform scales of 500 Kg capacity each with a resolution of 0.1 kg.
The supports are fixed on these scales that measure the two reactions. These scales are to be
suitably aligned, positioned and fixed to provide the desired span. The supports were fixed on
car jacks that provided an easy method of height adjustment to suit the different diameters of
bamboo that may come for testing. Application of Load is done by another car jack fixed into a
frame that has to be anchored to the ground. Deflection of the bamboo was measured with
reference to a 600 mm scale fixed in the frame.
6.2 Test Procedure: The load (sum of the two reactions) and corresponding deflections
are read on the scales and recorded, to determine the load deflection relationship. The results
showed this relationship was fairly constant and so the mean value was assumed as the
characteristic and is used to determine the value of E*I for the bamboo pole under test using the
relation
E*I = k* Wi / δi (1)
Where Wi and δi are increments in Load and deflections as measured and the value of K to be
estimated from K= l3/48 on the assumption of a central loading on a simply supported span (a
procedure similar to that in ISO). The value of E*I so determined suffers from significant errors
as the above assumption for k may not be exactly valid, and small errors in measurement of
length leads to much larger variations in result as the relationship has l3.
A trial run indicated that for a bamboo of about 52 mm diameter the loads were only about 44
kg at a deflection of 8 cm. For the load measuring scales that had a maximum capacity of 1000
Kg (2x500kg) these were too low in comparison with the guaranteed accuracy of the devices.
The set up was also rather unwieldy so a change in design was undertaken.
6.1.2 2m set up: The span was reduced to about 2m. This violated the recommendation
in ISO 22157 on length. However it provides the following advantages:
1 Increases the loads to about 8 times the 4m test values. Since the platform scales
were left unchanged the relative errors in load measurements got reduced.
2 The design needed only one platform scale, reducing the cost
3 The span was much more representative of the usual spans of purlins in bamboo
structures used for shelters
Test Setup for NCBT 2m
Figure 2
The set up is shown in Fig.2. The platform scale supports a beam built up of 2 steel
channels that in turn has the supports for the bamboo under test. Jacks are retained to provide
height adjustments for leveling, and to suit the bamboo diameter. V type supports are used to
provide stability and centering ability. The loading is also through Jack fixed below the top
plate in 4 column frame that is fixed to the lower frame of the scale. The movement of the
loading block is measured with the help of a digital vernier scale with a resolution of 0.01mm
and is the measure of deflection. The relatively large section channels, used as support beams
make the assumption of rigid supports reasonably valid.
Another innovation in the test procedure was to introduce an on-site calibration. An
initial test using the setup, with the positions of support blocks and loading block fixed is
conducted using a steel pipe as a reference piece. The value of (E*I)steel for this reference piece
can be estimated fairly accurately from well known values of E for steel (2.0*10^6 Kg/cm2 )
and of I from the dimensions of the tube that are fairly constant and easily measurable. The set
up is used to determine the W/delta for this piece and this result is used to determine the value
of Ks for this setup by
Ks= (E*I)steel * δsteel / W steel (2)
This value Ks is constant for the setup in a specific setting and has no errors due to
measuring errors in length and/or inappropriateness of the load deflection relationship. During
tests the values of W and δ for the piece under test is determined and the value of E*I is
determined from
E*I = (W/ δ)* Ks (3)
This procedure makes the estimate free of errors
arising out of a wrong assumed value of k in the formula E*I = k* W* l3/ δ
due to differences in nature of support
due to wrong measurement of l
due to wrong calibration of load meters (so long as they are linear)
due wrong calibration of the vernier scale
This makes the device and procedure fairly robust and suitable for use in field conditions
where accurate calibration of measurement devices can be a problem
7 Some test Results
Tables 1 to 5 gives the actual readings for loads and deflections observed on the
calibrating steel tube and 4 different pieces of bamboo. It may be pointed out that the device
used for application of load was a car jack and as such the rate of load application was neither
constant nor monitored. For the duration while noting the loads and deflection the jack was in a
fixed position. It was observed that the loads were slightly reducing with time (the resolution of
the scale is 0.5Kg). However the reduction was only about 2kg over about 2 minutes, that is
insignificant, considering the nature of the test. Tests were conducted with a maximum
deflection value between 4- 8 cm as compared to the design limit of approx 0.5cm (L/400).
Observations & Results – 2m NCBT
25-May Specimen Steel 4-Jun Specimen
Bamboo
F 1-Jun Specimen
Bamboo
G
2012 2012 2012
OD Thickness ID OD
OD
42.5 4.5 33.5 1 58.00 1 63.50
I E/104 E*I/104 2 54.00 2 59.10
98276.8 2 196553.6 3 58.00 3 59.10
Average 56.67 mm Average 60.57 mm
Length 5.10 m Length 5.00 m
Weight 5.10 Kg Weight 6.65 Kg
1.000 Kg/m 1.33 Kg/m
Steel Bamboo Bamboo
Load W Vernier Load W Vernier Load W Vernier
Kg mm kg/mm Kg mm kg/mm kg mm kg/mm
72.05 8.15 23.15 7.76 35.95 9.65
146.1 16.07 9.350 44.20 14.77 3.003
74.75 18.83 4.227
218.85 23.65 9.471 64.80 21.48 3.036
109.65 26.76 4.307
282.6 30.32 9.497 84.65 27.62 3.097
140.30 33.67 4.344
340.3 36.35 9.512 103.10 33.33 3.127
169.65 40.23 4.372
391.5 41.93 9.457 120.60 38.84 3.135
195.10 46.21 4.353
136.30 43.85 3.135
217.55 51.78 4.310
152.95 48.48 3.188
240.15 57.16 4.298
Mean 9.457 Ks Mean 3.089
ks Mean 4.319
Ks 20783.06 20783.06 E*I 64194.12
20783.06 E*I 89762.11
Table 1
The bamboo poles used in the tests were approximately 5m long. Data presented in the
tables include raw data (actual readings). The diameter varies significantly. Pie gauge was used
to record the diameters at the two ends and in the centre. The load/deflection values have been
obtained using an averaging approach rather than the best fit line as the method is simpler and
more suitable for field application. In the 5 tests that were made the maximum deviation from
the average was 3% of the mean value in Case 5, which indicates the procedure provides a
fairly reliable value of E*I
Observations & Results – 2m NCBT
1-Jun Specimen
Bamboo
H 4-Jun Specimen Bamboo I 4-Jun Specimen
Bamboo
J
2012 2012 E*I/104 2012 E*I/104
OD OD OD
1 55.00 1 70.00 1 60.00
2 54.00 2 65.00 2 54.00
3 52.60 3 66.00 3 51.30
Average 161.6 Mm Average 67 mm Average 55.1 mm
Length 5.00 M Length 5.00 m Length 5.10 m
Weight 4.90 Kg Weight 7.95 Kg Weight 6.15 Kg
0.980 Kg/m 1.59 Kg/m 1.21 Kg/m
Bamboo Bamboo Bamboo
Load W Vernier Load W Vernier Load W Vernier
Kg mm kg/mm kg mm kg/mm kg mm kg/mm
28.85 9.09 51.05 8.05 35.00 10.59
55.25 17.16 3.271 104.75 16.03 6.729 66.65 19.96 2.978
80.15 24.76 3.274 155.10 23.39 6.783 95.15 28.10 3.209
101.75 31.17 3.302 198.00 29.80 6.756 121.55 35.30 3.337
123.15 37.61 3.306 238.10 35.81 6.738 145.05 41.85 3.388
141.55 43.03 3.321 275.45 41.58 6.693 167.90 48.14 3.428
158.80 48.34 3.311 309.80 46.84 6.671 187.20 53.76 3.429
175.00 53.42 3.297 204.45 59.19 3.401
ks Mean 3.297 ks Mean 6.728 ks Mean 3.295
20783.06 E*I 68530.83 20783.06 E*I 139834.40 20783.06 E*I 68476.32
Table 2
7 New design process
The design process is explained by using the design of a Purlin as an example .The value
of design load in N/m2 on the roof as a combination of dead load, live load and wind load is
determined following the usual process specified in the housing codes. This value does not
depend on any of the parameters of the roof support system (purlin is one part). Typical values
are Dead Load comprising, coverings (150-400) and the estimated weight of purlins (60-150 )
[17] in case of steel structures, Live loads between (400-750) depending on the inclination or
slope of the roof . Method of Estimating the Wind load is rather complex for discussion here but
we may assume its maximum value to be typically 1200 N/m2, acting upward. The codes
permit increasing the allowable stress values by 33% when wind loads are considered. Let us
assume that the design load (Ld) on purlins is 1000 N/m2.In the design of the roof support
system we have to consider the following:
1 The span of the truss (A): Depends on the requirement of the building. However we
may take it typically as 6m and 9m
2 The distance between trusses (B) typically between 0.5 and 2m in steps of .25m
3 The number of nodes (n) on the bottom tie in the truss, n is always odd
The inclination of roof (Θ), the span of the truss (A), and the number of nodes(n)
combine to provide the internodal distance (Cr ) on the top rafter of the truss and the designer
has a free choice on number of nodes.
Cr = A*sec Θ/(n+1) (4)
Assuming that purlins are placed on the nodes of the top rafter only (a good practice that
ensures the rafter is subjected to mainly axial loads) we get the main loading parameter, namely
w the load per unit length on the purlin as
w = Ld* Cr = Ld* A*sec Θ /(n+1) (5)
And the purlin is to be designed as a beam carrying the uniformly distributed load w
calculated above on a span of B. While the purlins as we use are long lengths of bamboo
spanning over several trusses, and hence continuous beams, we treat them as simply supported
in the design for keeping the process simple and it also provides a built in factor of safety
The purlin would therefore be subjected to:
A Max BM M = w*B2/8 (6)
B Max Shear Force F = w*B/2 (7)
C Deflection (ISO800) δ = 5*w*B4/384*E*I = w*B4/(75*E*I) < B/325 (8)
A bamboo pole that is to be used as the purlin should have an assurance that its
E*I > (325/75)*B3*w (9)
Safe Shear Force F > w*B/2 (10)
Safe BM M > w* B2/8 (11)
Let us consider we have a pole which had the test results of Bamboo G for this
application. The test indicated that the value of E*I = 89700*104 kg/m2 . Since there was no
failure upto the maximum load in the test (240 kg), it means that the safe Shear stress is greater
than 120Kg, and safe Bending moment is greater than 120 Kg.m
Since we have a control over the value of Cr in the design process, that controls the
value of w ,we explore the variation of w with the span length B subject to the above
constraints . This is shown in Table 3.
Safe design load w for Bamboo G
SPAN – m
AC.T.V 0.5 0.8 1 1.2 1.5 1.8 2
E*I 897 Kg.m2 1656 404 207 120 61 35 26
M 120 Kg.m 3840 1500 960 667 427 296 240
F 120 Kg 480 300 240 200 160 133 120
Table 3
While the safe value of w is the highest at the lowest span of 0.5 m and the lowest at the
longest span of 2m, according to all the three criteria, the nature of variation is quite different.
Under the given set of properties a span of 1m seems a good choice with the safe value of load
w as 207 Kg/m
9 New Approach to Grading for Structural Applications
The author (16) suggested that the following additional parameters from the NCBT be
also recorded:
o Value of E*I
o Value of weight/length
o Value of safe bending moment M = W*L/4
o Value of Safe Shear Force F = W/2
Culms that have taper and out of straightness within certain narrow limits are suitable
for good quality structural applications. These may further be sorted and grouped as per the
following order:
• Diameter : in steps of 3, 5, or 10 mm. Customer may like to use culms of almost the
same diameter in specific application areas to get good appearance
• Value of E*I, M, and F : Specified values indicates suitability for use in Specific
Situation
• Length : An important characteristic to match the requirement
Culms that are excessively tapered or curved may again be sorted as per scheme above
but with wider steps as they can be used for less critical applications
Grading leads to the following advantages:
o Bamboo Culms sorted in groups with specified dimensional, stiffness, and strength
properties.
o Customer gets what one needs, less wastage and work at site
o Assured stiffness and strength provides assurance of quality, and acceptability of
structure at lowest cost.
o Implemented at plantations, it will enhance incomes in the villages
o It will also enhance demand
10 Conclusions:
1 The test metric E*I gives a measure that is adequate for design of roof purlins
2 The method of test developed gives a fairly good estimate of this value
3 This estimate is significantly better than what can be achieved from results of tests
based on determination of E and I as per ISO 22157 separately and then finding the
product
4 The test set up developed is simple in construction, rugged in construction, and fairly
cheap
5 The metrics and the procedure for its determination are Novel
6 The tests are non destructive.
7 The procedure provides a good first basis for grading bamboo for structural
applications.
11 Further Actions:
1 Extended test runs under field conditions using the developed set up are needed to
identify operational problems and to improve the design
2 Results should be used as a measure, and the metric as one of the parameters of
grading.
3 Application of this process of grading to produce batches of significant numbers
(100 or more) of a single grade from a large lot, and number of batches of differing
properties.
4 Study of the pattern for populations at different sources
5 The existing test setup (2m span) provides a good measure of E*I. However tests
with different spans e.g 1.5m, 1m or 0.75m may be conducted. Results from these
tests can be used to verify the accuracy of the measure
6 The test method also provide further useful information such as values of the safe
bending moment and safe shear force. However these values are underestimates as
no failures were observed. Extensive tests will provide cases of failure, and thus help
us refine the process (e.g. the value of span) that gives better estimates, while it still
remains nondestructive
7 Further work on design of structures based on the approach used in progress
8 Refine the process of testing and design to an extent that it becomes a candidate for
inclusion in ISO
12 Impact on Rural Econonomies
1 The process of grading and design based on the new approach will enhance the
confidence in bamboo structures, and hopefully increase their acceptability.
2 Increased acceptability may lead to greater use in good rural housing, thus improving
the life style at affordable costs for the masses
3 Increased demand should result in more plantation and hence cleaner air
4 Assurance of Better quality will enhance value of the product
5 Cheap and Rugged test set up can be used by the producers to grade their produce
and get better price
6 Increased Housing will provide employment opportunities in the villages
7 Increased use in Villages near the places it is grown, reduces the wasteful use of
energy in transportation to far away markets, and makes a much larger contribution
to local economies.
8 This could be one of the several initiatives needed to improve life in villages
9 Increased use of bamboo in structures reduces the use of concrete, brick and steel
that have a large carbon footprint
13 Acknowledgements
• Dr. P Sudhakar - for invitation (2010) to join in the NAIP and thus introducing me to
this area
• Nripal Adhikari - for continued interaction and providing access to a lot of literature
• INBAR - for engaging me as a Consultant and providing financial and
organizational support in the development
• Students - for discussing their projects,
14 References
[1] Klaus Dunkelberg IL – Team, Bamboo as a Building Material- Straight Rods.
BAMBUS - Bamboo, IL-31, Institut fur leichte Flachentraqwerke (IL), Universitat
Stuttgart, Leitung Frei Otto im Sonderforschungsbereich SFB 64 1985
[2] IS 6874, Method of Tests for Round Bamboo, 1973, Reaffirmed 2002, 2008(First
Revision)
[3] ISO 22156, Bamboo Structural Design:
[4] ISO 22157 (Part I & 2) Bamboo - Determination of physical and Mechanical
properties - 2004
[5] National Building Code of India ,Part 6, Structural Design, Section 3 Timber and
Bamboo , 3B Bamboo
[6] Suresh Bhalla, Scientific Design Of Bamboo Structures ,
www.bambootechnologies.org
[7] KF Chung, S J Chan, Design of Bamboo Scaffolds , Technical Report No.23,
INBAR rcatice
[8] Jorge A. Gutierrez. “Structural Adequacy of Traditional Bamboo Housing in Latin
America” Report No.19. INBAR
[9] Jules J. A. Janssen , Designing and Building with Bamboo ,Technical Report
No 20 INBAR
[10] Cheng-Jung Lin · Ming-Jer Tsai · Song-Yung Wang, Nondestructive evaluation
techniques for assessing dynamic modulus of elasticity of moso bamboo,
(Phyllosachys edulis) lamina, J Wood Sci (2006) 52:342–347 © The Japan Wood
Research Society 2006
[11] Suneet Tuli1, Smita Chugh2, etal, Thermal Wave Imaging of Defects in
Bamboo, Proceedings of the National Seminar & Exhibition on Non-
Destructive Evaluation NDE 2009, December 10-12, 2009
[12] David Trujillo, Prospects for a method to infer non-destructively the
strength of bamboo: a research proposal ,Third International Conference on
Sustainable Construction Materials and Technologies, August 18 – August 21 2013,
Kyoto Research Park, Kyoto, Japan
[13] Private Communication ,GII grant “Bamboo in Urban Environment”
[14] NAIP , DARE/ICAR (India) Annual report 2008-09 pp 134-135
[15] Private Communication , Progress Report 2010 National Agricultural
Innovation Project (NAIP) Subproject Bamboo as a green engineering material in
rural housing and agricultural structures for sustainable economic growth (2008-
2012)
[16] Ramesh Chaturvedi , A Novel Test Method for Mechanical Properties of
Bamboo.,Summit on SUSTAINABLE HABITAT , IIT Delhi & INBAR Delhi
December 2011 PP
[17] V. N Vazirani et.al ; Steel Structures, Khanna Publishers Delhi 2005
[18] Ramesh Chaturvedi ; ‘Grading Bamboo Culms for Structural Applications’,
Asia Regional Bamboo and RattanWorkshop INBAR & MOEF New Delhi,
December 10-11, 2013.