1) Bamboo is a sustainable building material that grows quickly without fertilizer and can support heavy loads while being flexible. It has advantages over steel like lower carbon emissions and stronger earthquake resistance.
2) Bamboo has mechanical properties similar to steel but requires treatments like waterproofing before use as reinforcement. Its strengths include high tensile strength, flexibility, and availability worldwide. However, it is also brittle with irregular shapes.
3) Bamboo can be used for roofing and modern truss designs with connectors have improved load distribution over traditional designs. While bamboo reinforcement has advantages for green building, it is not recommended for all structures due to disadvantages like water absorption and lack of consistency between pieces.
Bamboo as a sustainable building material of the future
1. 1
Compilationby : MohammadFaisal Shaikh
B.Ar.(Mumbai)- M.Ar. (Mumbai)
EditorialAssessment by: Er. JavedAlamShaikh
Bamboo a Sustainable Building Material
of the Future
“As 21st Century Steel & Roofing Material”
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Bamboo the “ GREAT WILD GRASS ” Bamboo has been regarded as a sacred
species from the time immemorial. Its very nature symbolizes growth, grace, patience,
strength, flexibility, endurance and longevity has been woven not only physically but also
Meta physically over the livelihoods of people throughout the ASIA.
Is Bamboo the Sustainable
Building Material of the Future ?
One of the biggest benefits, and the reason why
bamboo be the material of the future, is its
sustainability. It’s technically a wild grass and
there are more than 1000 species growing
unimpeded in tropical regions. Bamboo can
support heavy loads plus it is flexible and
earthquake-resistant.
Bamboo can be a very sustainable crop , a fast
growing grass, it requires no fertilizer and self-
regenerates from its own roots, so does not need
to be replanted
Bamboo is really exceptional green building
material. It is a sustainable material that requires
very less to energy to nurture, restrain soil
erosion, supplies bio fuel, extend wildlife refuge
and manufacture a wholesome food source for
both humans and wildlife.
What are the Advantages of
bamboo in construction?
One Its elasticity allows it to weather storms
and earthquakes that would break or crumble
other building materials. Due to the high
composition of water and silicate acid bamboo
has natural fire resistance. It can withstand
temperature up to 400 degree Celsius.
Bamboo is making its mark in architecture with
better then ever strengths, shooting up and
above. With the great green draught throughout
the world and the need for sustainability spikes
Bamboo is now becoming popular material for
architect working on humanitarian projects in
ASIA and beyond, owing to its sustainable
nature, low cost, strength, and flexibility.
3. 1. Abstract
2. Introduction
3. Bamboos
4. Distribution of bamboos
5. Properties of bamboos
6. Properties of bamboos
7. Comparison between steel and bamboos
3
8. Selection and preparation of bamboos
9. Construction principles
10. Roofing with bamboos
11. Advantages of bamboo as structural member
12. Disadvantages of bamboo as structural member
13. Conclusion
14. References
4. 4
In recent years, steel prices have soared. For
developing countries, steel is difficult to obtain
because of expensive prices, and for the construction
industry, usage of steel is currently limited heavily.
The production of steel has high consumption of
fossil fuels, so, the steel discharge in the construction
of structures has been presented, showing the
possibility of drastic reduction by research institutes.
Meanwhile, for developing countries, it is
important to make the development of buildings
construction; low cost, no requirement of
sophisticated technologies and reliable construction
methods.
The present presentation deals with cost-wise
comparison of steel reinforcement with bamboo
reinforcement. The utilization of bamboo reinforcement
as replacement of steel reinforcement is gaining
immense importance today, mainly on account of the
improvement in the economical aspect combined with
ecological benefits.
Recently, in the attention in response to global
warming issues and sustainable society, the
manufacturing using natural materials has become
actively. Bamboo, low cost, fast growing, and broad
distribution of growth, is expected to contribute
significantly to earthquake-resistant construction and
seismic retrofit technology in the developing countries
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Bamboos belong to the grass family Poaceae
(Gramineae). In India, there are 125 indigenous as
well as exotic species of bamboos belonging to 23
genera. Bamboo forests occupy an area of 10.03
million ha, roughly 12.8% of the total forest area in
the country.
Bamboos are some of the fastest-growing plants
in the world, due to a unique rhizome-dependent
system. Certain species of bamboo can grow 35
inches/890 mm within a 24-hour period, at a rate of
0.00003 km/h (a growth of approximately 1 mm (or
0.02 inches) every 2 minutes).
Historical use of bamboos.
Around 16th – 17th Centuries BC this time, bamboo
was being used to manufacture bows, arrows and other
hunting materials as the wood is plentiful and
extremely durable. Of course, bamboo was also being
used to create household items and even the structure
of the house itself.
6. Table1.0 : Distribution of Bamboo
Genus
Numberof
Species
Distribution
Bambusa C37
Tropical & subtropical Asia, especially in
monsoon & wet tropics; mostly cultivated
Cephalostachyum 11
From north eastern Himalayas to Thailand
and Mindoro; mountain to lowland forest
Dendrocalamus C.29
From Indian subcontinent throughout South-
East Asia; dry and humid tropics
Dinochloa C.20 Malaysia; hill and lowland dipterocarp forest
Gigantochloa C.24
South-East Asia, wild or cultivated;
humid tropics
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The geographical distribution of
bamboos is governed largely by the
conditions of rainfall, temperature, altitude
and soil. Most of the bamboos require a
temperature from 8 degree c to 36 degree
c, a minimum annual rainfall of 1000 mm
and high atmospheric humidity for good
growth.
Following are the some of the certain
species across the world
7. Properties
Steel (FE500) as per
B/S -IS1786-2008
Bamboos
Yield strength 379.02 N/MM2 180.6 N/MM2
Ultimate tensile strength 500.23 N/MM2 220.88 N/MM2
Elongation in % 20 15.07
Carbon Emission
(for 3m length to
support 300kg load)
15 to 17 0 to 0.1
Mass per 3 meter length 10kg 6.5kg
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Some specific properties of Bamboo
(bambusa and dendrocalamus) are as given below:
Specific gravity : 0.575 to 0.655
Average weight : 0.625 kg/m
Modulus of rupture : 610 to 1600 kg/cm2
Modulus of Elasticity: 1.5 to 2.0 x105 kg/cm2
Ultimate compressive stress-:794 to 864 kg/cm2
Safe working stress in compression :105 kg/cm2
Safe working stress in tension:160 to 350 kg/cm2
Safe working stress in shear: 115 to 180 kg/cm2
Bond stress : 5.6kg/cm2
Properties Red brick Bamboos Steel
Density 1920 kg/m3 0.3 to 0.4
7750 to 8050
kg/m3
Thermal
conductivity
0.6
0.04 to
0.12
50.2
Carbon emission 1.3 0 to 0.1 15 to 17
Composition
By weight
Silica(sand),-50%
Alumina(clay)-20%
Lime-2 to 5%
Natural
Grade
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The following factors should be
considered in the selection of bamboo
culms (whole plants) for use as
reinforcement in concrete structures:
Use only bamboo showing a
pronounced brown colour. This will insure
that the plant is at least three years old.
Select the longest large diameter
culms available.
Do not use whole culms of green,
unseasoned bamboo.
Avoid bamboo cut in spring or early
summer. These culms are generally weaker
due to increased fibre moisture content.
The culms should be well seasoned
before use so that sweetness of the bamboo
will be lost and insect attacks will be
minimised which is used for construction
8.2.1 Sizing :
Splints are generally more desirable than
whole culms as reinforcement. Larger
culms should be split into splints
approximately 3/4 inch wide. Whole
culms less than 3/4 inch in diameter can
be used without splitting. Splitting the
bamboo can he done by separating the
base with a sharp knife and then pulling a
dulled blade through the stem. The dull
blade will force the stem to split open; this
is more desirable than cutting the bamboo
since splitting will result in continuous
fibres and a nearly straight section
8.2.2 Seasoning :
When possible, the bamboo should be cut
and allowed to dry and season for three to
four weeks before using. The culms must
be supported at regular spacing to reduce
warping.
When seasoned bamboo, either split
or whole, is used as reinforcement, it
should receive a waterproof coating to
reduce swelling when in contact with
concrete. Without some type of coating,
bamboo will swell before the concrete
has developed sufficient strength to
prevent cracking and the member may
be damaged, especially if more than 4
percent bamboo is used. The type of
coating will depend on the materials
available.
A brush coat or dip coat of asphalt
emulsion is preferable. Native latex, coal
tar, paint, dilute varnish, and water-glass
(sodium silicate) are other suitable
coatings.
In any case, only a thin coating
should be applied; a thick coating will
lubricate the surface and weaken the
bond with the concrete.
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In general, techniques used in conventional reinforced concrete construction need not the changed when bamboo is to be
used for reinforcement.
Bamboo reinforcement should not be placed less than 1-
1/2 inches from the face of the concrete surface. When using
whole culms, the top and bottom of the stems should be
alternated in every row and the nodes or collars, should be
staggered. This will insure a fairly uniform cross section of
the bamboo throughout the length of the member, and the
wedging effect obtained at the nodes will materially increase
the bond between concrete and bamboo.
Clear spacing between bamboo rods or splints should
not be less than the maximum size aggregate plus 1/4 inch.
Reinforcement should be evenly spaced and lashed together
on short sticks placed at right angles to the main
reinforcement. When more than one layer is required, the
layers should also be tied together. Ties should preferably be
made with wire in important members. For secondary
members, ties can be made with vegetation strips.
The same mix designs can be used as would
normally be used with steel reinforced concrete.
Concrete slump should be as low as workability will
allow. Excess water causes swelling of the bamboo.
High early-strength cement is preferred to
minimize cracks caused by swelling of bamboo
when seasoned bamboo cannot be waterproofed.
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9. Construction principles….
9. Construction principles….
Bamboo must be securely
tied down before placing the
concrete. It should be fixed at
regular intervals of 3 to 4 feet to
prevent it from floating up in the
concrete during placement and
vibration.
9.3 Placement of Concrete
9.3 Placement of Concrete
Additional diagonal tension
reinforcement in the form of
stirrups must be used near the
supports. The vertical stirrups
can be made from wire or
packing case straps when
available; they can also be
improvised from split sections
of bamboo bent into U-shape,
and tied securely to both
bottom longitudinal
reinforcement and bent-up
reinforcement. Spacing of the
stirrups should not exceed 6
inches.
In flexural members
continuous, one-half to two-thirds
of the bottom longitudinal
reinforcement should be bent up
near the supports. This is especially
recommended in members
continuous over several supports.
11. 10. Roofing with bamboos
10. Roofing with bamboos
It is a proven shield against forces of nature
or animals and are considerably light weighted
which makes them easy to install.
Bamboo is one of the best roofing materials
and provides ample sturdiness to the structure.
The bamboo roofs encompass purlins, rafters
and trusses.
12. 10.1.1 Traditional Bamboo truss.
10.1.1 Traditional Bamboo truss.
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10.1 Different Roofing designs
10.1 Different Roofing designs
In the past bamboo truss was
made by putting the bamboo poles
together and strapping a rope around
them. He issue with this type of
bamboo truss connectors is that the
load of the roof was not equally
distributed. There is friction which
may compromise the strength of the
roof.
10.1.2 Modern Bamboo Truss.
10.1.2 Modern Bamboo Truss.
New joiners and connectors have
been designed in recent times. Thanks to
advancement in technology, skilled
engineers and architects. These joiners and
connectors can be made in various shapes
and sizes. This depends on the number of
poles to be connected and the design of
the roof.
With the modern joiners there is rarely
any friction between the poles. The weight
is equally distributed. Incorporation of
little steel helps in overcoming the
problems faced in traditional system. steel
joiners do not need a lot of investment and
hence the cost of the entire Bamboo
structure is low.
The amount of skilled labour
required is also low. This means even in
the rural areas these structures can be
built using modern joiners.
10.1.3 Halved bamboo columns
10.1.3 Halved bamboo columns
Another way of covering the roof
with bamboo is to cut open the
bamboo exactly in half. The nodes
within he bamboo column are
removed and cut into adequate sizes.
The bamboo halves are then placed in
an interlocking manner. One have
faced the
ground and the other faces the sky.
The half facing the ground is holding
2 halves facing the sky.
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It has almost zero carbon emission. Some of the species of
bamboo has more tensile strength than steel.
Due to its high elasticity nature, structures made with
bamboos are more capable of withstand against earthquake.
It does not requires sophisticated tools or equipment for its
cutting.
In each of its nodes, bamboo has a dividing and transverse
wall that maintains strength and allows bending, thus preventing
rupturing when bent.
Easily available across the world.
It is lighter material thus it can be use in substitution of other
same property heavier materials.
It has very low thermal conductivity.
Resistance of electricity.
No skilled labour is required for cutting and construction.
11. Advantages of bamboos as structural member
11. Advantages of bamboos as structural member 12. Disadvantages of bamboo as structural member
12. Disadvantages of bamboo as structural member
Water absorption is very high, the bamboo used as a reinforcement
absorb water from concrete mixture thus it reduces the strength of
concrete as well as its tensile strength.
It requires waterproofing agent before its placement.
Since bamboo is a natural material, every bamboo has not same
tensile and compressive strength.
Thus we have to check the properties of every bamboo each time before
placing.
Most important it is a brittle material hence it will not give any
warning before its failure.
Due to smooth surface of bamboo the bond between concrete and
bamboo will be very less.
It is not fire resistance.
Every bamboo has irregular shape even a single bamboo differs
its dimensions after one or more nodes.
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13. Conclusion
13. Conclusion
As per above study we can conclude that bamboo has similar
characteristics as steel but it has major faults too like
waterproofing, brittle nature, low bonding with concrete, requires
more maintenance than steel. It cannot be recommended for
reinforcement in sky scrapers, important buildings, dams, and other
certain construction.
On the other hand, bamboo has very low carbon emission
and low thermal conductivity as compare to other building
materials which cannot be ignorable thus bamboo can be used in
low rise buildings such as G+1 and G+2 and where the steel is not
available. Thus, In the green building concept use of bamboo
reinforced concrete may be recommendable.
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14. REFERENCES – OTHER TOPICS OF STUDIES
14. REFERENCES – OTHER TOPICS OF STUDIES
Bamboo a SustainableBuilding Material of the Future
“As 21st Century Steel”
OTHERRELAVENT TOPICS OF STUDIES
“Replacement of Steel by Bamboo Reinforcement’’
“Investigation on properties of bamboo as reinforcingmaterial in concrete’’
“Bamboo reinforced concrete construction’’
“ Design Bamboo As Green Alterative To Concrete And Steel For Modern Structures.”
Complilation/ Edited by :
Mohammad Faisal Shaikh
B.Arch (Mumbai)
M.Arch. Urban Design (Mumbai)
Editorial Assessment by : Javed AlamShaikh