Comparative Study of Bamboo (Ikra) Housing System with Modern Construction Practices Maulik D.Kakkad M.E Student, Applied Mechanics Department, L. D. College of Engineering, Ahmedabad, India [email protected]Capt. C.S.Sanghvi Associate Professor, Applied Mechanics Department, L. D. College of Engineering, Ahmedabad, India [email protected]Abstract— North-eastern region has two famous indigenous construction practices, which have been emerged over a period of time and proven their resilience against earthquakes. These techniques are Assam Type House & Thatch House. The present work has been made to compare bamboo-Assam type housing with modern construction practices. To compare the Seismic force, stress-concentration acting on the different structural systems, these housing-systems are modeled with different loading condition in design software. Here Assam type (Ikra- bamboo) housing-system is modeled & for modern construction practices, Reinforced & Confined masonry and system is modeled. For simulation of earthquake-shaking, time-history analysis is performed in software. Keywords- bamboo (ikra) housing, reinforced masonry, Indigenous housing technology, confined masonry I. INTRODUCTION Earthquakes are not common phenomena in most parts of the world. Hence, houses in most rural areas as well as urban areas are not built to withstand seismic forces, resulting in heavy causalities even in moderate earthquakes. In some parts of the world, however, where earthquakes are common, people have incorporated the critical elements of quake resistance in their indigenous construction method. It seems unreasonable to state that simple, unsophisticated, non-engineered, timber or bamboo and masonry structures might be safer in large earthquakes than new structures of reinforced concrete, but such has proven to be the case in a number of recent earthquakes, including the Izmit and Düzce Earthquakes in Turkey of 1999, the Bhuj earthquake in India of 2001, and the Kashmir earthquake in Pakistan of 2005. II. BAMBOO HOUSING –IKRA HOUSING [1] Traditional construction in north-eastern region consists mostly of typical bamboo houses, known locally as ‘Ikra’, and also known as Assam-type housing. These housing typologies are common throughout the Northeast India. Majority of such houses are used for residential purposes. Typically these houses are built with light weight locally available material like bamboos, wooden planks, thatch etc. Such houses have a proper system of bamboo/wooden beam-column and fulfil the earthquake safety requirements of rectangularity and simplicity. Ikra houses are single-storey structures consisting of brick or stone masonry walls up to about 1 m above the plinth. This masonry supports the walls consisting of bamboo woven together with a wooden frame, and plastered with cement or mud plaster. The roof generally consists of GI sheets supported on wood/bamboo trusses, which laterally connect the parallel walls. Bamboo superstructure is connected to the masonry foundation walls using steel angles, and flats with bolts and nails. There were no reports of any significant damages to Ikra structures during past earthquake [2] . These housing types have demonstrated some of the basic principles of earthquake safe construction of non- engineered buildings like appropriate sitting and location on firm soils, good building configuration i.e. its form and shape in plan and elevation; location and size of major structural elements; number, location and size of openings; and connection details of non-structural elements with main structural system. Due to proper connection between different elements, such houses have a proper integral action due to which they act as a single unit. Fig. 1 Bamboo housing system –Ikra housing Fig. 2 Bamboo strips plastered with mud or cement. 13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India National Conference on Recent Trends in Engineering & Technology
Transcript
Comparative Study of Bamboo (Ikra) Housing System with Modern Construction Practices
Abstract— North-eastern region has two famous indigenous construction practices, which have been emerged over a period of time and proven their resilience against earthquakes. These techniques are Assam Type House & Thatch House. The present work has been made to compare bamboo-Assam type housing with modern construction practices. To compare the Seismic force, stress-concentration acting on the different structural systems, these housing-systems are modeled with different loading condition in design software. Here Assam type (Ikra-bamboo) housing-system is modeled & for modern construction practices, Reinforced & Confined masonry and system is modeled. For simulation of earthquake-shaking, time-history analysis is performed in software.
Earthquakes are not common phenomena in most parts of the world. Hence, houses in most rural areas as well as urban areas are not built to withstand seismic forces, resulting in heavy causalities even in moderate earthquakes. In some parts of the world, however, where earthquakes are common, people have incorporated the critical elements of quake resistance in their indigenous construction method. It seems unreasonable to state that simple, unsophisticated, non-engineered, timber or bamboo and masonry structures might be safer in large earthquakes than new structures of reinforced concrete, but such has proven to be the case in a number of recent earthquakes, including the Izmit and Düzce Earthquakes in Turkey of 1999, the Bhuj earthquake in India of 2001, and the Kashmir earthquake in Pakistan of 2005.
II. BAMBOO HOUSING –IKRA HOUSING[1]
Traditional construction in north-eastern region consists mostly of typical bamboo houses, known locally as ‘Ikra’, and also known as Assam-type housing. These housing typologies are common throughout the Northeast India. Majority of such houses are used for residential purposes. Typically these houses are built with light weight locally available material like bamboos, wooden planks, thatch etc. Such houses have a proper system of bamboo/wooden beam-column and fulfil the earthquake safety requirements of rectangularity and simplicity.
Ikra houses are single-storey structures consisting of brick or stone masonry walls up to about 1 m above the plinth. This masonry supports the walls consisting of bamboo woven together with a wooden frame, and plastered with cement or mud plaster. The roof generally consists of GI sheets supported on wood/bamboo trusses, which laterally connect the parallelwalls. Bamboo superstructure is connected to the masonry foundation walls using steel angles, and flats with bolts and nails. There were no reports of any significant damages to Ikra structures during past earthquake [2].
These housing types have demonstrated some of the basic principles of earthquake safe construction of non-engineered buildings like appropriate sitting and location on firm soils, good building configuration i.e. its form and shape in plan and elevation; location and size of major structural elements; number, location and size of openings; and connection details of non-structural elements with main structural system. Due to proper connection between different elements, such houses have a proper integral action due to which they act as a single unit.
Fig. 1 Bamboo housing system –Ikra housing
Fig. 2 Bamboo strips plastered with mud or cement.
13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering & Technology
III. MODERN CONSTRUCTION PRACTICES
The recent practices in construction of houses are load bearing system and Reinforced concrete frame system. Both the systems are very popular throughout the India and around the world.
For the comparison of the both the systems, the same dimensions for these systems.
IV. MODEL CONFIGURATION
A. Ikra housing model
For the model, a real life structure school building located near Dispur, Assam is modeled in software. The plan dimension of the building is 8m x 16m.
Fig 3 Model of bamboo (Ikra) housing system
In bamboo (Ikra) housing system, for main structural member bamboo is used. In the Ikra system as shown in Fig.[3]. The bamboo is used as structural member. The modulus of elasticity of bamboo is 20000000 kN per squaremeter [15} and the density of bamboo is taken as 7.3575 kN per cubic meter, Poisson’s ratio is 0.3 and critical damping is 0.00152[18] as per INBAR (international network for bamboo and rattan). The brick wall is used for modelling. And it is rigidly connected with plinth as well as with bamboo. The green mashing shown in Fig [3] shows the brick masonry [7].
In this system the wall is made of bamboo strips and it is plastered with mud. So for dynamic analysis of the model, the wall is ignored.
B. Reinforced brick masonry system model
In this system the model dimension is taken same as the Ikra housing. For the wall, brick masonry is used as shown in Fig.[4].
For the modelling of reinforced masonry Sap-2000 v.14 is used. In sap the wall is created by layered shell element. In shell element there are three different layers considered, first and third layers are made of brick masonry and the second middle layer is made of rebars. The spacing of rebar is taken 300 mm as per draft IS 1905(IITK-GSDMA)[20].
Fig.4. Model of reinforced brick masonry system.
C. Confined brick masonry system
For the Confined masonry system, the dimension of the model is taken same as above two systems. For this system wall is taken as brick wall, and for the tie beam and column reinforced concrete is used. The dimensions of tie beam and column is as per the EERI (seismic design guide for confined masonry-2011) [19].
Fig.5 Model of confined brick masonry system
V. RESULTS
A. Seismic force on different systems
For determining the frequency and response of different housing systems, time history analysis is used. The time history data of Al-Centro 1940 and Bhuj 2001 earthquakes are used for time history analysis. The natural frequencies of different housing system are as shown in Table I.
TABLE I FREQUENCY OF DIFFERENT HOUSING SYSTEMS FROM THE TIME
HISTORY ANALYSIS
Housing system Frequency (Hz)
Bamboo housing ( Ikra housing system) 1.529
Reinforced brick masonry system 4.380
Confined brick masonry system 3.574
From the frequencies of the different housing system the time period, response reduction factor, zone factor, and
13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering & Technology
importance factor can be work out from the IS 1893-2002[4].
As the material used in bamboo housing is flexible (modulus of elasticity is very less compared to other material) and critical damping offered by bamboo is also less so that the frequency of bamboo housing is less compared to other two systems.
From the time period, Sa/g (Average response acceleration coefficient) can be derived from as per the IS-1893-2002[4].For5% damping. For the different construction material used in housing the correction factor is multiplied as per IS-1893-2002[4]. The damping ratio of different housing system is shown in Table II.
TABLE II CORRECTED SA/G AS PER IS 1893 – 2002 (FOR HARD SOIL)
Housing system Sa/g (5% damping)IS 1893-2002
Critical damping offered by in system (%)
Corrected Sa/g as per system
Bamboo housing ( Ikra housing )
1.53 1.523 2.706
Reinforced brick masonry system
2.50 9 2.08
Confined brick masonry system
2.50 8 2.13
From the model of different structural systems, the seismic mass of the system is worked out and for determining the seismic force static co-efficient method is used.
TABLE III SEISMIC FORCE ON DIFFERENT HOUSING SYSTEM
Housing system Seismic force on different housing system. kN
Bamboo housing ( Ikra housing ) 14.55Reinforced brick masonry system 112.00Confined brick masonry system 124.13
The chart shows the comparative analysis of seismic force on different housing system.
B. Stresses in structural systems
For the stresses concentration, in software the surface is generated, and the results are as shown in Table IV. For the comparison of stresses principal major, principal minor, von mis and shear stresses is considered.
TABLE IV STRESSES IN DIFFERENT HOUSING SYSTEM (MPA)
Fig. 5 View of stresses in Bamboo (Ikra) housing system.
Fig. 6 View of stresses in Reinforced Brick masonry.
Reinforced brick masonry system 1.28 0.29 0.9 0.24
Confined brick masonry system 1.18 0.1883 0.88 0.54
13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering & Technology
The chart shows the principal major, minor, von Mis and shear stress in different housing system. These stresses are determined from the software.
VI. CONCLUSION
As bamboo is very flexible material and also light weight material, the seismic force in bamboo system is very less compared to modern housing systems. Seismic force on the bamboo housing system is 12.97% and 11.72% of reinforcedbrick masonry and confined brick masonry systemsrespectively. In Assam (Ikra) housing system bamboo is used as main structural element because bamboo is ductile material & its performance is improved under earthquake event.
In bamboo housing system the stresses are higher than modern housing system. It can be concluded that material used in system is properly utilised.
REFERENCES
[1] H.B. Kaushik, K. Dasgupta D. R. Sahoo G. Kharel“ Reconnaissance report, Sikkim earthquake of 14 February 2006 “
[2] H.B. Kaushik, K. Dasgupta, D. R. Sahoo G. Kharel, ”Performance of structures during the Sikkim earthquake 14th February 2006 “.
[3] R.Nath , Dr. J. Pathak, Dr. B.Sharma, Dr. P. J. Hazarika “ Assam type house- the traditional earthquake resistant construction practice in Assam “.IIT-R, Disaster mitigation in housing in India - An agenda for future, March 19-20 , 2010
[4] IS: 1893-2002, “Criteria for Earthquake Resistance and Construction of Buildings”, Bureau of Indian standards, New Delhi.
[5] World housing encyclopedia – An encyclopedia of housing construction in seismically active areas of the world- EERI and IAEE, www.world-housing .net.
[6] IS: 4326-1993 “Code of Practice for earthquake resistant and construction of buildings” Bureau of Indian Standards, New Delhi.
[7] A.A.Khan, C.Ghosh, “Traditional Earthquake Safe Housing Practices of North East India “. Training Program-2010, NIDM, Ministry of Home Affairs, Govt. Of India, New Delhi.
[8] Allen G. Nobel “A Global Survey of Structural Forms and Cultural Functions “– Traditional building- [ch-6, pp 103-121].
[9] (Ms) R Tiwari, Dr (Ms) A Sharma, Dr M Pandey, “Bamboo and Built Environment Sustainability Issues “. IE Journal-AR, Volume-90, Oct-2009.
[10] IS: 6874-1973 “Method of test of round bamboo “Bureau of Indian standards, New Delhi.
[11] IS: 8242-1976 “Method of test for split bamboo “Bureau of Indian standards, New Delhi.
[12] Traditional housing system – case study (India) http://www.archinomy.com.
[13] K.Shyamasundar, J. Vengala “Promotion of bamboo Housing system & Recent Developments “.IPIRTI-TRADA, Research report, 2006-2007
[14] D. R. Mitch “Structural behavior of grouted-bar bamboo column bases “ University of Pittsburgh 2010.
[15] INBAR “Mechanical properties of bamboo “ Vol.2- 2002.[16] E.M.N.SILVA, “Numerical modeling of bamboo as a functionally
graded element”, www.abmtenc.civ.pucrio.br, Brazil.[17] K S Nanjunda Rao “properties and behaviour structural masonry”,
Research Article, Department of Civil Engineering, IISc-Bangalore.[18] S. Amada R. S. Lakes “Visco elastic properties of bamboo “Journal
of Materials Science, 32, 2693-2697, (1997).[19] Seismic design guide for low rise confined masonry building, Jan-
2011, EERI and IAEE Confined masonry network.[20] NICEE, IITK-GSDMA, Guidelines for structural use of Reinforced
masonry. Aug-2005
13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering & Technology
![Comparative Study of Bamboo (Ikra) Housing System with ... · In bamboo (Ikra) housing system, for main structural member bamboo is used. In the Ikra system as shown in Fig.[3]. The](https://static.documents.pub/doc/80x56/5f0b23007e708231d42f07b0/comparative-study-of-bamboo-ikra-housing-system-with-in-bamboo-ikra-housing.jpg)
