Vernacular And Contemporary Use Of Bamboo Environmental Sciences Essay

Bamboo is one of the oldest known and used materials by mankind. Due to the rise in the environmental concerns, wood has become a critical resource. Bamboo is also very effective in sequestering carbon and helps in reducing the green house emissions. Bamboo is one of the few materials which have an enormous range of uses. It can be used as a construction material, for interiors, in furniture design, as a decorative plant and it is also a delicacy in the culinary world. Bamboo has a substantial history of application in construction due to its structurally desirable properties. Since bamboo is light weight, it is used in other industries like construction of boats and as structural members in kites and planes since primitive times. Bamboo has been used in China to make paper, cloth and Rayon. The tensile strength of bamboo makes it a crucial factor in construction of the bridges across rivers in India and China.

The use of bamboo in various industrial processes has shown a great potential for the production of composite materials and components which can be effectively used in the structural and non-structural applications in building construction. Most importantly, bamboo is a renewable raw material.

Bamboo is a group of giant and fast growing perennial grass. It is native to the tropical, sub tropical and temperate areas of all the continents other than Europe. Bamboo can be found in a wide range of climates, like the cold areas of the Indian Himalayas to the hot tropical areas of Asia, Africa and Latin America.

Vernacular and contemporary use of bamboo:

The native people of Asia, Africa Central and South America used bamboo for housing purposes. This architecture was categorised as vernacular, because it used the locally available resources and traditions to address to the local issues and climatic conditions, without an architect intervening. The vernacular architecture of any place is the reflection of the environmental, social and historical context in which it exists. It is basically the architecture that has been carried on since the old times or the native traditional architecture of a place. In many countries, the poor people in rural areas used bamboo to build their houses. This bamboo was obtained after its use as scaffolding in building construction. Since the primitive people used bamboo for building their houses, and the bamboo that they used, was the used bamboo from the construction industry, it came to be known as the “poor man’s timber”. A shift from the use of bamboo as a building material occurred only after the advent of modern materials like concrete, brick, steel etc. The use of these materials changed the mind set of people and their use became a status symbol, because they were stronger and more durable than bamboo.

Bamboo is adaptable to most climates, and is found in large numbers in the Asian sub-continent; many areas in these regions have adopted the use of bamboo as a building material, and created their own vocabulary for designing with bamboo. After harvesting and treatment against insects, local materials and techniques can easily be adapted with bamboo for building construction.

Availability of bamboo:

Bamboo is mainly found in the chain islands of Oceania (Thailand, Singapore, islands surrounding Philippines and Micronesia), warm areas of South America (Brazil, Argentina, Ecuador and Columbia), Central America (Mexico, Panama, Jamaica, Haiti, Cuba and Honduras), Africa (Madagascar, Nicaragua, South Africa, democratic Republic of Congo and Kenya), North America and Asia (China, India, Japan, North and South Korea and Bangladesh).

Out of all the bamboo species available, roughly 300-500 species are found in China alone. In all, Asia contains 64% of the world’s bamboo diversity.

Most of the developing countries of the world are located along the equator. These countries have a fast growing population and have an ever increasing need for housing. These areas have climate that is conducive for bamboo growth. The use of bamboo as a construction material in these areas is suitable, because it is a fast growing, inexpensive and locally available resource and has excellent construction qualities.

Bamboo can be found in areas at the sea level as well as at altitudes of about 3800m. Majority of the bamboo species grow at temperatures from 25-50 degrees Celsius. Sandy loams to loamy clay soils are suitable for bamboo growth. Bamboo cannot thrive in saline soil.

CHARACTERISTICS OF BAMBOO:

The biological classification of bamboo is as follows:

Kingdom : Plantae  Phylum ( Division) : Magnoliophyta 

Class: Liliopsida  Subclass: Commelinidae 

Order: Cyperales  Family: Gramineae (Poaceae) 

Subfamily: Bambusoideae  Tribe: Bambuseae 

Subtribe: Bambusinae

There are two types of bamboos, the running type (herbaceous) and the clumping type (woody). Of these two, the running type is mostly found in the temperate climates or in the high mountainous regions of the tropics and they produce both, a culm and rhizomes. A ‘culm’ is the above ground vertical shoot and ‘rhizomes’ are the long underground shoots. Generally, the bamboos found in the tropical regions are the clumping type. The clumping type has a tendency to produce large diameter and thicker walled culms, but has very short rhizomes. Bamboo which is three to six years old is suitable for the purpose of construction.

Herbaceous bamboos sprout from the same main root and grow in dense clumps. They have thin culms and many leaves. In the woody bamboo, many culms sprout from the same stem since it grows horizontally beneath the soil. The characteristic of woody bamboo is that it grows thick and tall. The straight culms are most suitable as a building material. Most of the woody bamboos can grow in temperatures of up to -17 degrees Celsius. The herbaceous type of bamboo cannot tolerate freezing temperatures.

Since bamboo belongs to the grass family, it grows by stretching upwards and not in concentric rings like trees. Most of the species of bamboo grow hollow and have varying thickness of the outer wall. Diaphragms or nodes divide the central chamber of the stalk into sections at regular intervals. This gives bamboo its stiffness.

The shape of bamboo, its hollow and brittle nature – all these together pose several challenges while designing with bamboo. Also, the areas in which bamboo is usually found have a temperate or tropical climate and hence rainfall is ample in these areas. The bamboo that is used in these areas which are humid must be protected from moisture otherwise it may rot and fail. Similarly, when exposed to severe sunlight, bamboo expands and contracts due to the heat and this can result into the bamboo splitting and cracking. In such cases, the bamboo must be protected from sunlight.

As a building material, bamboo has many advantages owing to its lightweight, hollow and versatile nature. Bamboo can be used to design buildings that allow natural ventilation by creating breathable walls, floor and roof structure. The shape and size of bamboo also provides for versatility in design. This type of construction is suitable in areas like the tropics which tend to have a humid and hot climate.

Properties of bamboo:

Tensile properties:

Bamboo has a tensile strength equal to that of steel owing to the strong fibres within its shoot. This strength is greater parallel to the shoots as compared to the strength perpendicular to the grain direction. This is an important consideration while designing connections for load transfer.

Compressive properties:

The compressive strength of bamboo is due to the hollow cylindrical shape of the culm, where the strongest fibres are along the outer edge and stiff nodes at equal intervals along the length which act as diaphragms. The bamboo shoot would possess a relatively high compressive strength axially if it were to grow in a perfectly straight manner.

Bending strength:

The fibres that run along the length of the bamboo make it most vulnerable to excessive bending, which causes the bamboo shoot to lose its circular form and hence its strength. There are numerous parameters like age, position of the culm, moisture content, skin surface and distribution node which greatly affect the bending strength of the bamboo shoot.

Shear strength:

One of the most important drawbacks of bamboo in terms of its material properties is its low shear strength. The walls of the shoot are relatively thin, and contribute significantly to the cracking and splitting of the culm.

Buckling failures:

Owing to its slender nature, the bucking strength of bamboo is an important factor that needs to be taken into consideration while designing.

Density:

After conducting various studies, it has been found that some species of bamboo that grow in the Asian and American continents have a density greater than that of timber. The average density is 700-800kg/meter cube; however this value varies with each individual species.

Seismic resistance:

Bamboo shoots have a low modulus of elasticity and a high strength to weight ratio of the culm and hence, bamboo structures react well to earthquakes. Since bamboo structures are light weight as compared to concrete or steel, they cause relatively small inertial forces from earthquakes. Bamboo also has a reduced response to ground movements owing to its flexible nature.

CONTEMPORARY USE OF BAMBOO IN BUILDING DESIGN:

Owing to its structural properties and versatility, bamboo has manifold uses in the construction industry. It can be used for making walls, both interior and exterior, for making roofs, as scaffolding, for flooring, for making partitions etc. Bamboo has been used by man in the construction of temporary structures, huts, mud houses etc. since a long time. Over the years, the methods of construction used since the primitive times, have evolved and adapted themselves. Even though there have been advances in the techniques used in bamboo construction, the basic principles from the age- old methods have remained the same.

Case studies:

The Green School, Bali, Indonesia:

Architect: PT Bambu / Aldo Landwehr, John Hardy.

The campus of the Green School is sustainable and is beautifully designed along?? both the sides of river Ayung in Sibang Kaja, Bali. It is situated in a jungle with a variety of native trees and plants and organic sustainable gardens. The campus of the Green School is powered using a number of alternative energy sources like bamboo sawdust hot water and cooking system and a hydro -powered vortex generator and solar panels. The campus has spaces like classrooms, gyms, assembly areas, offices, cafes, faculty housing etc. Bamboo is the locally available and sustainable material which has been used so as to exploit its maximum potential. Bali is located along the equator and has a tropical climate. This climate is suitable for bamboo construction. The Green School understands and respects the vernacular architecture of the region and goes a step further than just creating modern spaces using traditional materials.

The Inspiration Office, Kochi, Kerala, India:

Architect: Prasad Jonathan. D. W.

The premises of the Inspiration office in Kerela, India cover an area of about 2750 sq.ft. It is the first building of its kind. It is an experimental design, which has attempted to develop a new technology (bamboo reinforced plaster). They have then used this plaster in walls, floors and roofs. RCC columns, ferro-cement beams and very little reinforced plaster have been used along with bamboo to achieve the beautiful design of this building. One of the remarkable characteristic of the building is that out of the total bamboo used, 25% was from areas in the vicinity of the site. The concept of the design is based on an open plan. This helps in allowing the communication flow, but keeps the privacy intact. The office is divided into public spaces, semi- private spaces, private spaces and executive spaces. Micro-steel reinforced mortar bamboo composite is used for infill floors, walls and roof of the building. There is a difference of about 4-5 degrees between the interior and exterior temperature on an average.

BAMBOO as a low impact construction material:

Bamboo is a giant grass and can grow up to 4 feet in a day. The shoot of bamboo can be cut like grass and the roots inside the earth will grow a new shoot, this makes it a highly renewable resource. Bamboo has been used in building construction since the ancient times. It is a traditional building material which is available at a much lower price than other traditional building materials. It also has advantages in terms to sustainability, flexibility and growth time as compared to the other traditional materials.

The characteristic of bamboo that makes it a sustainable material is that some varieties of bamboo can grow up to 4.3 inches a day. Bamboo can be harvested in three to five years. In the first 180 days of its growth, bamboo will reach nearly 100 feet. Bamboo is instrumental in carbon sequestration because it grows in a greater density and faster than a forest with trees. In comparison to other wood products, bamboo requires little energy for curing after it is cut. On an average, the medium size culms require about four months to dry up completely. Harsh chemicals are not necessary to preserve bamboo; it can be preserved using natural substances and non- toxic chemicals. Simple techniques like keeping it off the ground and keeping it dry will increase the life of bamboo as a building material. Concrete can be reinforced with bamboo instead of steel. This would reduce the impact on the environment, as the production of steel is more energy consuming and steel has more embodied energy as compared to bamboo.

Bamboo is a very good example of sustainability, in terms of it being a plant as well as a building material. Numerous tests have been conducted to evaluate the performance of bamboo for compressive and tensile strengths as compared to traditional wood species. Due to its light weight, bamboo performs better in shear than materials like concrete which have greater mass.

The bamboo which is suitable for building construction can grow in poor soils since it requires very little nutrients. The woody bamboo which is suitable for construction purpose reproduces asexually by spreading and this continues during the growing season. This growing season varies according to the climate, but it normally lasts for about four to six months of a year, generally when the temperatures are warm and rainfall is regular. This means, that no special care needs to be taken for growing bamboo, and hence as a result, ….

Using bamboo that is grown locally as a building material would help in saving the shipping cost and consume less fossil fuel. Preferably, bamboo that is grown within a radius of 150-200kms from where it needed should be used for construction because it has low embodied energy and hence it is more environmentally friendly.

CONCLUSIONS:

Bamboo is typically found in the tropical and temperate regions of the world. In most of the areas where bamboo is found, the native species, that are readily available, are used for construction. Bamboo is also used for various other purposes like furniture design, textile making, as food, for making instruments etc.

Bamboo is rapidly renewable as a building material and it can be harvested almost every 5 years, which means that one can grow his own house! Even though controlling the growth and spread of bamboo is a difficult task, bamboo growth is advantageous because it converts carbon dioxide into oxygen more effectively than trees. The physical properties of bamboo allow it to be bent into various shapes whenever required, when heat is applied. Since the use of bamboo as a building material has not gained as much popularity as a few other materials, there is a lack of construction systems which are needed to work with bamboo. Similarly, standardisation of bamboo construction techniques is also necessary.

While there are many individual species of bamboo that are on the verge of extinction, the cultivation of bamboo as a building material is harmless. The use of bamboo as a building material has more advantages than disadvantages. If properly cultivated and harvested, bamboo can be grown and used as a building material where it is necessary in the highly populated areas of the world. Bamboo as a building material is inexpensive, lightweight, regenerative and sustainable and it needs to be explored to its full potential. Bamboo needs to be mainstreamed in regions where it is available in plenty and easily and needs to be used in modern architecture.

Abstract:

This essay discusses the probable use of bamboo as a low impact building material in tropical, sub- tropical and temperate regions of the world, where it is found in abundance. Bamboo belongs to the grass family, it is evergreen and perennial; it is thus becoming an increasingly popular building material. Bamboo owes this to its credentials; it grows very fast, it is easy and cheap to cultivate and it is extremely strong.

We live an age, where the construction industry is ranked as one of the least sustainable industries and it eats up most of the non-renewable resources available globally. The choice of a building material is generally made after considering the technical, functional, financial and design requirements. However, in the last few decades, sustainability has become a huge problem and hence, the environmental impact of a building material is now becoming the prime criterion. Thus the qualities of bamboo are very appealing as a low impact building material.

Today, we need to emphasise on finding innovative solutions for building materials which impact the environment to the minimum. Bamboo is a potential sustainable alternative to the conventional structural materials like concrete, steel and timber in the regions where it is grown in plenty, and the climate is suitable for bamboo construction.