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 materialø Is viewed as a material preferred only by the poor or for temporary constructionsø Unpopular in conventional construction due to low durability, lack of structural design data, exclusion from building codes etc.
Facts about bambooø 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.
advantagesø 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.
advantagesø 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.
How to protect bamboo…UNTREATED BAMBOOø 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 yearsø Natural durability also depends on the species of the bambooPRE-HARVEST AND POST HARVEST PRECAUTIONSø Felling during low sugar content season i.e. dry seasonø Felling of mature bambooø Post harvesting transpirationø Water soaking
How to protect bamboo…BORAX – BORIC ACID PRESERVATION TREATMENTDepending on the At the preservationdiameter of the bamboo, treatment pool, bamboodifferent sized drill bits, soaks in borax-boric acidattached to a long steel solution (1:1.4) for 2 daysrod, are used to drill into to allow the mineral to Bamboo is removedthe centre of the bamboo penetrate all the nodes and stackedculms throughout their and diaphragms. vertically so thewhole length. solution can drain and be reused.
How to protect bamboo…BORAX – BORIC ACID PRESERVATION TREATMENT Preservative solution isNext, the bamboo The bamboo poles recharged after four cycles bypoles are left to are left to dry adding water and the chemicals.bask in the sun slowly in a Preservation treatment costs adepending on the cool, dry place minimum charge of INR 4.50amount of sunlight until they are used per pole. for construction.
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 itselfø The swelling and shrinkage of bamboo in concrete create a seriouslimitation 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 thebamboo surface followed by a coating of fine sand.
How to protect bamboo…NEEM SEED OIL 90TREATMENT 80 70ø Oil obtained from neem seeds 60can be used to improve water 50resistance and dimensional 40stability of bamboo culms 30particularly at high oil- 20treatment temperature. 10 0ø Bamboo samples soaked in hotneem seed oil at 60°C for 4hours had better waterresistance and dimensional Soaked bamboo samples at roomstability than samples soaked in temperature for 24 hoursoil at room temperature for 24 Soaked bamboo samples at 60°C for 4 hourshours. SHRINKAGE REDUCTION
Bamboo foundationsCOMPOSITE BAMBOO-CONCRETE FOUNDATIONSSingle Post Footing Strip Footing
Bamboo foundationsBAMBOO PILESø Bamboo compacts softsoil, thus increasing thebearing capacity of soil.ø The friction provided by theconstruction-grade bambooincreases its load-bearingcapacity.ø Treated split bamboo piles 8mlong and 80 to 90mm indiameter were filled with A sustainable house incoconut coir strands wrapped Thiruvananthapuram, Kerala where bamboowith jute. piles have been used as foundation . The foundation is further strengthened by bamboo reinforced concrete.
Bamboo foundationsBAMBOO 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.
RESISTANCE TO EARTHQUAKESø High residual strength to absorbshocks and impacts.ø Flexure coupled with its very lowmass. ø A bamboo house in Bhutan that withstood an earthquake that occurred at Sikkim (epicenter) measuring 6.9 in September 2011ø Prototype house built with bamboosheet roofing and bamboo-reinforced ø 30 houses at the epicenter of aconcrete walls withstood a simulated 7.6 magnitude earthquakeearthquake measuring 7.8 on the survived without any damage inRichter scale Costa Rica in 1991
Comparative analysis Energy consumption during construction876543210 Concrete structure Wood structure Bamboo structure
Limitations and drawbacksFew considerations currently limit the use of bamboo as a universallyapplicable construction materialø 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.