Bamboo is a versatile building material with several advantages such as strength, flexibility, earthquake resistance, low cost and minimal environmental impact. However, untreated bamboo has low durability. Various treatments like borax-boric acid preservation, neem oil treatment can improve the durability. Bamboo can be used for walls, foundations, columns, beams and roofing. It provides cost and energy benefits compared to concrete while maintaining structural strength. However, limitations include jointing techniques, flammability and lack of codified design guidance.
2. INTRODUCTION…
ø Bamboo has been in wide usage since ancient times as a low-cost material
for houses, bridges etc.
ø Recently started appearing in designer homes as flooring, walling and
paneling material
ø Is viewed as a material preferred only by the poor or for temporary
constructions
ø Unpopular in conventional construction due to low durability, lack of
structural design data, exclusion from building codes etc.
3. Facts about bamboo
ø Bamboo is a perennial grass and not a
tree as is commonly perceived.
ø 1450 species are found in diverse climates
across the world, however, not all of these
are suitable for construction.
ø One of the fastest growing plants on
Earth. Its growth rate ranges from 30cm
to 1 m in 24 hours.
ø The strongest part of a bamboo stalk is
its node, where branching occurs.
ø Bamboo has also long been used as
scaffolding; the practice has been banned
in China for buildings over 6 storeys but
is still in continuous use for skyscrapers
in Hong Kong.
4. advantages
ø Strength - Bamboo is an
extremely strong natural fibre, on
par with standard hardwoods,
when cultivated, harvested,
prepared and stored properly.
ø Flexibility - Bamboo is highly
flexible. During its growth, it may
be trained to grow in
unconventional shapes. After
harvest, it may be bent and
utilized in archways and other
curved areas.
ø Earthquake-resistance - It has a
great capacity for shock
absorption, which makes it
particularly useful in earthquake-
prone areas.
5. advantages
ø Lightweight - Bamboo is extremely lightweight. Consequently, building
with bamboo can be accomplished faster with simple tools than building
with other materials. Cranes and other heavy machinery are rarely
required.
ø Cost-effective – Economical, especially in areas where it is cultivated and
is readily available. Transporting cost is also much lesser.
ø Durability - As long-lasting as its wooden correlates, when properly
harvested and maintained.
6. How to protect bamboo…
UNTREATED BAMBOO
ø Untreated bamboo has the following life
spans in different conditions
> Exposure to soil and atmosphere = 1-3 years
> Under cover = 4-7 years
> Very favourable conditions = 10-15 years
ø Natural durability also depends on the
species of the bamboo
PRE-HARVEST AND POST HARVEST
PRECAUTIONS
ø Felling during low sugar content season i.e.
dry season
ø Felling of mature bamboo
ø Post harvesting transpiration
ø Water soaking
7. How to protect bamboo…
BORAX – BORIC ACID PRESERVATION TREATMENT
Depending on the At the preservation
diameter of the bamboo, treatment pool, bamboo
different sized drill bits, soaks in borax-boric acid
attached to a long steel solution (1:1.4) for 2 days
rod, are used to drill into to allow the mineral to Bamboo is removed
the centre of the bamboo penetrate all the nodes and stacked
culms throughout their and diaphragms. vertically so the
whole length. solution can drain
and be reused.
8. How to protect bamboo…
BORAX – BORIC ACID PRESERVATION TREATMENT
Preservative solution is
Next, the bamboo The bamboo poles recharged after four cycles by
poles are left to are left to dry adding water and the chemicals.
bask in the sun slowly in a Preservation treatment costs a
depending on the cool, dry place minimum charge of INR 4.50
amount of sunlight until they are used per pole.
for construction.
9. How to protect bamboo…
ø During the casting and curing of
concrete, reinforcing bamboo absorbs
water and expands
ø The swelling of bamboo pushes the
concrete away
ø Then at the end of the curing
period, the bamboo loses the
moisture and shrinks back almost to
its original dimensions leaving voids
around itself
ø The swelling and shrinkage of bamboo in concrete create a serious
limitation in the use of bamboo as a substitute for steel in concrete.
ø One effective treatment is the application of a thin layer of epoxy to the
bamboo surface followed by a coating of fine sand.
10. How to protect bamboo…
NEEM SEED OIL
90
TREATMENT
80
70
ø Oil obtained from neem seeds 60
can be used to improve water 50
resistance and dimensional 40
stability of bamboo culms 30
particularly at high oil- 20
treatment temperature. 10
0
ø Bamboo samples soaked in hot
neem seed oil at 60°C for 4
hours had better water
resistance and dimensional
Soaked bamboo samples at room
stability than samples soaked in temperature for 24 hours
oil at room temperature for 24 Soaked bamboo samples at 60°C for 4 hours
hours. SHRINKAGE REDUCTION
12. Bamboo foundations
BAMBOO PILES
ø Bamboo compacts soft
soil, thus increasing the
bearing capacity of soil.
ø The friction provided by the
construction-grade bamboo
increases its load-bearing
capacity.
ø Treated split bamboo piles 8m
long and 80 to 90mm in
diameter were filled with A sustainable house in
coconut coir strands wrapped Thiruvananthapuram, Kerala where bamboo
with jute. piles have been used as foundation . The
foundation is further strengthened by
bamboo reinforced concrete.
13. Bamboo foundations
BAMBOO PILES
ø The sections
were then tied
with galvanised
iron wire. After
installation of the
piles @2m c/c by
drop hammer, the
area is covered
with a 2.5m
surcharge of sandy
material.
15. RESISTANCE TO EARTHQUAKES
ø High residual strength to absorb
shocks and impacts.
ø Flexure coupled with its very low
mass.
ø A bamboo house in Bhutan that
withstood an earthquake that
occurred at Sikkim (epicenter)
measuring 6.9 in September 2011
ø Prototype house built with bamboo
sheet roofing and bamboo-reinforced ø 30 houses at the epicenter of a
concrete walls withstood a simulated 7.6 magnitude earthquake
earthquake measuring 7.8 on the survived without any damage in
Richter scale Costa Rica in 1991
20. Comparative analysis
Energy consumption during construction
8
7
6
5
4
3
2
1
0
Concrete structure Wood structure Bamboo structure
21. Limitations and drawbacks
Few considerations currently limit the use of bamboo as a universally
applicable construction material
ø Jointing techniques - Although many traditional joint types exist, their
structural efficiency is low. Considerable research has been directed at
the development of more effective methods.
ø Flammability - Bamboo structures are not fire-resistant, and the cost of
treatment, where available, is relatively high.
ø Lack of design guidance and codification - The engineering design of
bamboo structures has not yet been fully addressed. There is little or no
data containing specifications of bamboo.