Bamboo is a building material or construction material throughout the world’s tropical & sub-tropical areas. Bamboo is a sustainable & versatile resource, with high strength and low weight. That is the reason it is generally utilized in different forms of building construction, particularly for housing in rural areas.
Bamboo can also be utilized to make traps, cages, tools or instruments, weapons, bridges, pontoons, rafts, towers, fences, water wheels, irrigation pipes, and many different things. It is extensively perceived as one of the main significant non-lumber forest resources due to the high socio-economic advantages of bamboo-based items.
The world’s fastest-growing woody grass is Bamboo. It grows approx 7.5 centimeters to 40 centimeters a day, with the world record being 1.2 m in 24 hours in Japan. Bamboo grows 3 times faster than most other species. Species of bamboo that are commercially used usually mature in four or five years. Different harvests are feasible every 2nd year, for up to 120 years in some species & indefinitely in others.
Bamboo is also good for biomass creation. Bamboo is often introduced into the banks of streams or in other vulnerable areas, for rapid control of soil erosion; one bamboo plant’s closely matted roots can bind up to 6 m3 of soil.
Why Bamboo is used as a Building Material?
Housing is an essential requirement for the human being and is now becoming a burden for low-income and medium-income groups. Thus, we need cost economic housing and bamboo is the best building material or structural material, the result for that as:
- Bamboo is the fastest-growing renewable natural building material or construction material.
- The material is easily available & Eco-friendly.
- A bamboo is a viable option for steel, concrete & masonry as an independent building material.
- Bamboo is economical and easy to work with.
- Bamboo can be easily twisted, give the required shape & can give joints to suit the construction.
- Bamboo has good elasticity makes it is a very useful building material in regions with high risks of earthquakes.
- It is locally accessible material to some areas, which tries to carry the local tradition & vernacular Architecture of that place.
Main Properties of Bamboo
As discussed before that Bamboo is a practical option for steel, concrete, and brickwork. It is so because of its properties which are clearly mentioned below.
Bamboo is capable to withstand more tension than compression. The filaments of bamboo or fibers of bamboo run axially are of a highly elastic vascular bundle that has high tensile strength. The tensile strength of these fibers is higher than that of steel reinforcement, but it is not possible to construct connections that can transfer this tensile strength.
Slimmer tubes are superior in this aspect too. Inside the silicate external skin, axial parallel elastically fibers or filaments with a tensile strength up to 400 N/mm2 can be found. As a comparison, extremely strong wood fibers or filaments can withstand tension up to 50 N/mm2.
Compared to the bigger cylinders, slimmer cylinders have got, comparable to their cross-section, a higher compressive strength value. The slimmer tubes have better material properties because of the fact that bigger tubes have got a minor part of the external skin, which is more resistant to tension. The part of the lignin inner side of the culms influences the compressive strength, whereas the high portion of cellulose impacts the buckling and the tensile strength as it represents the building substance of the bamboo fibers.
The accumulation of highly strong fibers or filaments in the external parts of the tube wall also work positively in connection with the elastic modulus like it does for the tension, shear & bending strength. Enormous elasticity makes it a very helpful building material in areas with very high risks of earthquakes.
Bamboo is an anisotropic material. Properties in the longitudinal direction are totally different from those in the transversal direction. There are cellulose fibers or filaments in the longitudinal direction, which is strong and hardened, and in the transverse direction, there is lignin, which is soft & weak.
Bamboo shrinks more than wood it loses water. The canes tear apart at the nodes. Bamboo shrinks in a cross-section (c/s) of 10%-16% and a wall thickness of 15%-17%. Accordingly, it is essential to take important measures to prevent water loss when bamboo utilized as a building material.
The fire resistance is very good due to the high content of silicate acid. Filled up with water, it can stand a temperature of 400oC while the water cooks inside.
Flexural (bending) Strength
Where a deflection in the construction was unavailable and annoying, one could bend the recently harvested tubes so that you get a super elevation, which later will be compensated under the working load.
Especially for the manufacturing of bamboo tube jointing, it is essential to consider the shearing resistance. The impact of the distance of the shearing surface reduces with the growing length of the shearing surface.
Bamboo as a Building Material
Bamboo is a flexible material due to its high strength-to-weight ratio, easy workability, and accessibility. Bamboo requires to be chemically treated because of its low natural durability. It can be used in different manners for the structure of roof as a purlin, rafters & reapers, for flooring, windows & doors, walling, ceiling, manhole covers, etc.
The bamboo has strength practically identical to that of Teak and Sal. A frame is made using bamboo rafters, purling, etc for fixing the roof.
Bamboo Roofs Skeleton
Bamboo Roofs Skeleton is made up of bamboo truss/rafters over which solid bamboo purlins are placed & lashed to the rafter through G.I.wire. A halved bamboo mesh is made & is lashed to the purlins to cover the rooftop.
As the bamboo is light-weight it is beneficial for seismic-prone regions as its chances of falling are very less just because of flexibility & even if it falls it can be re-erected effectively with less human and property loss with fewer efforts & minimum cost. Bamboo walls can be constructed in many different ways.
- Whole stem halved or strips of bamboo can nail to one or both the sides of the bamboo frame.
- Bamboo strips used as bamboo frame/posts for inside walling.
- Cement or lime plastering can be done on the mud covering for better appearance and cleanliness.
It has been found that the bamboo in the vertical direction is more durable and lasting than in the horizontal direction. For partition walls or segment dividers, only a single layer of bamboo strips is used.
Bamboo Doors and Windows
Bamboo frames can replace timber frames properly to function. Bamboo mat shutters fixed to a bamboo frame which is pivoted to the wall face which can be used as a door. Small framed openings hinged to the wall can serve as windows.
Bamboo can be used as a flooring material because of its better wear and tear resistance and its flexibility properties. Entire culms act as a framework and the floor covering is done using split bamboo, bamboo boards, mats, etc by means of wire lashing these to the frame.
Bamboo can be used as reed boards which are made by flat pressing the reed at high temperatures. These reed boards are utilized in components like flooring, walls, ceiling, and roofing. They can also be utilized for partitions, doors, windows, etc.
Bamboo poles lashed together have been utilized as scaffolding in high-rise structures because of their strength and flexibility. The timber boards can be changed with bamboo culms & these can be lashed to the vertical culms.
For use as the foundation of the structure, the bamboo poles are directly driven into the ground. They need to, however, be pre-treated for insured from decay and fungi. This extends the life of the foundation beyond that of an untreated bamboo pole.
Advantages of Bamboo
The various advantages of bamboo are given below:
- Bamboo is a versatile material, thus can bend into any shape and also acts as earthquake-resistant material.
- It is a light, strong, and versatile material.
- The lightweight material permits it to be easily utilized during construction work.
- It tends to be reused many times to construct and reconstruct.
- Bamboo is not difficult to cut, handle, repair, reposition and maintain, without the requirement for sophisticated tools or equipment.
- Due to its extraordinary physical characteristics, bamboo is suitable for all types of structures and construction.
- Bamboo can be used for lasting and for impermanent developments.
- Bamboo can be used in combination with other types of building materials.
- It is environmentally friendly.
- Easily available to the poor.
- Self-renewing resource of nature.
- Speedily growing.
- Highly productive.
- Low-cost material.
Disadvantages of Bamboo
The major disadvantages of bamboo are as follows:
- It requires preservative treatment and if not treated well it gets attacked by the fungi.
- Bamboo should be used as it is available in shape as given by nature.
- There is a lack of sufficient design, guidance, and codes.
- Bamboo is a less durable material.
- Bamboo doesn’t bear weight width-wise. It can bear weight only along its lengthwise.
- Prone to catch fire very fast by the friction among the culms during wind & is seen to cause forest fires.