Bamboo

1. UNIT 5
Bamboo and Straw
bales as building
material
BAR 114 BUILDING CONSTRUCTION AND MATERIALS-I

2. ● Bamboo is woody and fast growing grass, which occurs
naturally on every major continent except Europe.
● There are almost 1200 species of bamboo in the world.
● Bamboo is grass, typically woody, and fast growing.
● Bamboo is a versatile, strong, renewable and
environment friendly material.
● It is exceedingly strong for its weight and can be used
both structurally and as a finishing material.
● Bamboo can be recombined into useful products and
elements such as flooring, ceiling, walls, partition walls,
trusses, domes, etc.
INTRODUCTION

3. RHIZOME
Rootstock from where roots shoots.
BUD
from where vertical growth starts.
CULM
woody hollow aerial stems of bamboo.
NODE
Node is the part of the stem of the plant
from which leaves, branches, and aerial
roots emerge. The distance between
each node is called the INTER NODE
PARTS OF BAMBOO

4. TENSILE STRENGTH:
The fibres of the bamboo run axially. The outer zone has the highest tensile strength.The tensile
strength of these fibres is higher than that of steel.
SHRINKAGE:
Bamboo shrinks more than wood when it loses water.
FIRE RESISTANCE:
Bamboo has good fire resistance due to high content of silicate.
ELASTICITY:
Due to its good elastic properties bamboo is much preferred in earthquake regions
PROPERTIES OF BAMBOO

5. Bamboo is adopted for various use and many products developed over the centuries by different cultures and
communities.
Unidirectional fibre, fast growing and simultaneously high strength both in tensile and compression makes this
material versatile, to be adapted in simple to complex forms and designs.
This quality of bamboo gives varied role in human cultural evolution than any other plant.
Bullock Cart
A Cutaway View Showing the
Construction of Comb Manipur,
India.
A Cutaway View of Bamboo
Suspension Bridge
VARIOUS USES OF BAMBOO

8. BAMBOO IN BUILDING CONSTRUCTION
● Bamboo has been used since 3500 BC and has more than 1500 documented uses.
● Bamboo is capable of providing solutions for shelter, livelihood, and food security for regions where
bamboo grows.
● They also provide ecological security by timber substitution.
● Bamboo is unique in that it is strong in both tension and compression. While tensile strength remains
the same throughout the edge of the bamboo plant, compressive strength increases as it gets older.
● Bamboo is an extremely strong fibre with twice the compressive strength of concrete, and roughly
the same strength to weight ratio of steel in tension.
● The strongest bamboo fibres have a greater shear resistance than structural woods, and they take
much longer to come to ultimate failure
● The structural advantages of bamboo are its strength and lightweight, whereby properly constructed
bamboo buildings are inherently resistant to wind and earthquakes.

9. The shape, size and quality of bamboo can vary greatly even
within a given species. The following grading rules will help in
selecting the best material for construction.
STRAIGHTNESS
The bamboo culms should be as straight as possible. A line
stretched between the tip and butt ends should not fall outside
of the culm.
TAPER
Change in diameter over length should be kept to a minimum
A maximum taper of 10mm per meter is acceptable for lengths
up to 3 meters.
NODES
Nodes are the strong points in the culm and should be used to
advantage especially at critical joints.
GRADING OF BAMBOO

10. ● Only bamboos with at least three year maturity shall
be used in construction.
● Bamboo culms that show signs of insect or fungi
attack should be avoided.
● Bamboo sizes are generally specified by minimum
diameter, wall thickness, and length.
● Column 80-100mm dia.
● Wall thickness 10-12mm dia
● Bamboo strips for infill panels 18-20mm wide,
8-10mm thick
SELECTION & SIZE OF BAMBOO

12. BAMBOO A BUILDING SYSTEM
A building system in which bamboo comprises of various elements and fulfils the main
structural role. Round bamboo columns and trussed rafters act as the main load bearing
element.
The system comprises of-
● FOUNDATION : individual column footings.
● COLUMNS : bamboo culms set in/on concrete footing.
● WALL INFILL : a grid of split bamboo covered in wire mesh and cement mortar.
● FLOOR : raised by 2- 3 brick courses, filled with rubble and screeded.
● ROOF STRUCTURE : bamboo rafters or trusses supporting bamboo purlins.
Corrugated bamboo mat board for roof covering.

13. Foundations are subsoil parts of the house which support the structure above.
The distance between two pedestal footings/ Piles shall not be more than 2.0 m for a bamboo
based superstructure.
The types of bamboo foundation identified are:
1. Bamboo in direct ground contact.
2. Bamboo on rock or preformed concrete footings.
3. Bamboo incorporated into concrete footings.
4. Composite bamboo/concrete columns.
5. Bamboo piles.
BAMBOO FOUNDATION

14. Bamboo in direct ground contact
● Bamboo, either on the surface or buried, can
decay within six months to two years.
Preservative treatment is therefore
recommended.
● For strength and stability, large diameter thick
walled sections of bamboo with closely
spaced nodes should be used.
● Where these are not available, smaller
sections can be tied together.

15. Bamboo on rock footings
Ideally, where bamboo is being used for bearings it should
be placed out of ground contact on footings of
A. either rock
Isolated foundations on each column are conformed by a
sandbag system enclosing a cavity for the accommodation
of the 4 culm column.
Anchors and some heavy aggregate could be added to
reinforce the foundation system.

16. Bamboo incorporated into concrete footings
The third approach is to incorporate the bamboo directly into the concrete footing. This can
take the form of a single posts or strip footing.

17. An innovative development involves the
casting of concrete extension to a bamboo
post using a plastic tube of the same diameter.
The result is a bamboo post with an integral,
durable foundation.
Composite Bamboo/ Concrete Columns

18. Bamboo Piles
Bamboo piles have been used successfully to
stabilise soft soils and reduce building
settlement.

19. BAMBOO FLOOR

20. Joist with primary members Joist with primary and
secondary members

25. BAMBOO WALL

32. AFFORDABILITY
Foundations are minimised, wall panels are non load bearing and can be reduced in thickness,
and the basic components (bamboo, wire, bolts, chicken mesh) are inexpensive.
SUSTAINABILITY & ENVIRONMENTAL IMPACT
Bamboo is a renewable resource with a short rotation period and can be grown on degraded land.
It is treated using environment friendly preservatives. The use of high energy embodied materials
(cement, steel) is minimized.
CULTURAL ACCEPTABILITY
The system offers traditional materials in a modern engineering context.
MERITS OF BAMBOO CONSTRUCTION

33. DURABILITY & SAFETY
All bamboo components are treated with safe preservatives to give extended life, the structure is
engineered to resist wind and seismic forces, and other imposed loads.
IMPROVED JOINTING TECHNIQUES
Wiring, bolting and strapping provide positive connections.
MODULAR CONSTRUCTION
Bamboo is suited to both prefabrication and fabrication in situ. All components are designed to be
prefabricated (ex infill grids, roof trusses) or prepared on site.
EASE OF ASSEMBLY
Only basic carpentry, masonry tools and skills are required to undertake construction.

34. ● Bamboo lacks natural durability which contributes to the view of bamboo as a temporary
material.
● Bamboo is susceptible to attack by insects and fungi and its service life could be as low as
one year when it is in ground contact.
● Bamboo cannot span very large structures and high rise buildings cannot be made from it.
● Bamboo Mat Corrugated Sheets absorbs moisture more as compared with asbestos and
plastic corrugated sheets. This may influence its durability in external utilisation.
DEMERITS OF BAMBOO CONSTRUCTION

35. THANK YOU