BAMBOO IN CONSTRUCTION

Material Type : Bamboo

       Bamboo is one of the oldest and most versatile building
materials with many applications in the field of
construction, particularly in developing countries. It is
strong and lightweight and can often be used without
processing or finishing.

      The diminishing wood resource and restrictions
imposed on felling in natural forests, particularly in the
tropics, have focused world attention on the need to
identify a substitute material which should be renewable, environmentally friendly and widely available. In
view of its rapid growth (exceeding most fast growing
woods), a ready adaptability to most climatic and
edaphic conditions and properties superior to most
juvenile fast growing wood, bamboo emerges as a very
suitable alternative.



INTRODUCTION :

       Bamboo is a renewable and versatile resource,
characterized by high strength and low weight, and is
easily worked using simple tools. As such, bamboo
constructions are easy to build, resilient to wind and
even earthquake forces and readily repairable in the event of damage.

1) Durability :

    Bamboo is subject to attack by fungi and
insects. For this reason, untreated bamboo structures are viewed as temporary with an expected life
of no more than five years.

2)Jointing :

   Although many traditional joint types exist,
their structural efficiency is low (Herbert et al. 1979).
Considerable research has been directed at the
development of more effective jointing methods.

3)Flammability :

   Bamboo structures do not behave
well in fires, and the cost of treatment, where available, is relatively high.

PRESERVATION OF BAMBOO :

       Bamboo is subject to attack by micro-organisms and
insects in almost any construction application. Unfortunately, like most lignocellulosic materials, bamboo has
very low resistance to biological degrading agents. The
service life is therefore mainly determined by the rate of
attack.

      A variety of methods to improve the durability of
bamboo have, however, been developed. Several of
these techniques are described here with the aim of
providing helpful guidelines to users.

DRYING OF BAMBOO :

       Green bamboo can have a moisture content of
100-150%, depending on the species, area of growth
and felling season. The chemical composition of
bamboo results in a comparatively higher hygroscopicity than wood. Additional problems in the drying of
bamboo occur because the material lacks an efficient
radial transport system and possesses a waxy coating.
Therefore, the major pathway for the loss of moisture is
from the ends of the culms.

     The liability to biological degradation and to deformation owing to excessive shrinkage (which occurs even
above the fibre saturation point) necessitates quick
drying of bamboo.

CONSTRUCTION METHODS :

        The majority of bamboo construction relates to rural
community needs in developing countries. As such,
domestic housing predominates and, in accordance
with their rural origins, these buildings are often simple
in design and construction relying on a living tradition of
local skills and methods. Other common types of
construction include farm and school buildings and
bridges.

       Further applications of bamboo relevant to construction
include its use as scaffolding, water piping, and as
shuttering and reinforcement for concrete. In addition,
the potential number of construction applications has
been increased by the recent development of a variety
of bamboo based panels.

SMALL BUILDINGS :

       Bamboo can be used to make all the components of
small buildings, both structural and non-structural, with
the exception of fireplaces and chimneys. It is, however, often used in conjunction with other materials,
cost and availability permitting.



FOUNDATIONS :

• Bamboo in direct ground contact 


• Bamboo on rock or preformed concrete footings 


• Bamboo incorporated into concrete footings 


• Composite bamboo/concrete columns 


• Bamboo reinforced concrete 


• Bamboo piles

WALLS :

        The most extensive use of bamboo in construction is
for walls and partitions. The major elements of a
bamboo wall (posts and beams) generally constitute
part of the structural framework. As such they are
required to carry the self-weight of the building and also
loadings imposed by the occupants, the weather and,
occasionally, earthquakes. To this end, efficient and
adequate jointing is of primary importance.

ROOFS :

       The roof of a building is arguably its most important
component - this is what defines a construction as a
shelter. As such, it is required to offer protection
against extremes of weather including rain, sun and
wind, and to provide clear, usable space beneath its
canopy. Above all, it must be strong enough to resist
the considerable forces generated by wind and roof
coverings. 

DOORS AND WINDOWS :

        In traditional types of bamboo building, doors and
windows are usually very simple in form and operation.
Bamboo doors can be side hinged or sliding,
comprising a bamboo frame with an infill of woven
bamboo or small diameter culms.

       In higher grade buildings, wooden doors are common.
Doors and shutters comprising bamboo mat board as
panelling, or as flush skins for hollow core doors offer another solution. 

       Bamboo windows are generally left unglazed and can
have bamboo bars, or a sash with woven bamboo infill.
The sash can be side hinged or sliding, or,
more commonly, top hinged to keep out direct sunlight
and rain. At night, windows are closed to protect
against insects and animals. Hinges are formed from
simple bindings, or connecting bamboo elements.

WATER PIPES AND GUTTERS :

       Whole bamboo culms, with the diaphragms removed, can be used as water pipes either below or above
ground.
Below ground: the system is usually gravity fed. 

       To
ensure watertight connections, the ends of the culms
can be reamed and fitted into short sections of metal,
pvc or bamboo pipe and suitably caulked.
To control insect attack, the trench can be treated with
insecticide before the pipes are laid. 

JOINTING TECHNIQUES IN BAMBOO :

        Effective jointing is fundamental to the structural
integrity of a framed construction. Furthermore, the
suitability of a material for use in framing is largely
dependent upon the ease with which joints can be
formed.
Because of its round, tubular form, jointing of two or
more bamboo members requires a different approach
to that adopted for, say, solid timber.

 

      Despite its
relatively high strength, bamboo is susceptible to
crushing, particularly of open ends. It is also characterised by a tendency to split; the use of nails, pegs,
notches or mortises can therefore result in considerable reductions in strength. Connections must also
cope with variations in diameter, wall thickness and
straightness.

 Traditional jointing methods rely principally on lashing
or tying, with or without pegs or dowels. The basic joint
types are:

TYPES :

Spliced joints 

Orthogonal joints 

Angled joints 

Through joints