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20320130406001 2

  1. 1. International Journal of Civil Engineering OF CIVIL ENGINEERING AND INTERNATIONAL JOURNAL and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME TECHNOLOGY (IJCIET) IJCIET ISSN 0976 – 6308 (Print) ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December, pp. 01-11 © IAEME: www.iaeme.com/ijciet.asp Journal Impact Factor (2013): 5.3277 (Calculated by GISI) www.jifactor.com ©IAEME REVIVAL OF TRADITIONAL EARTHQUAKE RESISTANT TECHNIQUE IN KASHMIR VALLEY, REPLACING TIMBER WITH BAMBOO IN DHAJJI DEWARI (BRACING SYSTEM), COMPARING COST AND STRENGTH ASPECTS 1 2 AAQIB MIR, YASIR SOFI, 3 WALEED QARI, 4 Prof Dr. A. R. DAR 1 (B TECH - Civil Engineering, NIT Srinagar) Working as a Structural Engineer in PUNJ LLYOD Engineering (Gurgaon) 2 Pursuing Masters in Structural Engineering at NIT Srinagar) 3 Working as Project Engineer at Waagner-biro(Dubai) 4 (H.O.D at NIT Srinagar- Civil Engineering Department) ABSTRACT This paper is focused on reviving the old traditional earthquake resistant technique (Dhajji Dewari) in Kashmir Valley which falls in seismic zone V, this technique proved to be of great help in mitigating earthquakes of the past. In Kashmir the old vernacular technique has been replaced with modern construction of concrete, brick and stone masonry buildings, hence making it seismically unsafe. The primary reason for destruction of traditional technique was high cost of timber. The research work is focused on replacing the timber in dhajji dewari with bamboo thus making it economically cheap and also increasing its strength many folds. Thus various models of dhajji dewari were tested first with timber and then it was replaced with bamboo for lateral loading in the laboratory. As a result, comparison of cost and strength was drawn in a tabulated and graphical manner and best configuration was identified by applying lateral (seismic force) on various configurations of timber and bamboo. Keywords: Concrete, Dhajji Dewari, Lateral Loading, Masonry Buildings, Mitigating, Seismically Unsafe, Seismic Zone, Vernacular. 1
  2. 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME INTRODUCTION Experience in past earthquakes has demonstrated that many common buildings and typical methods of construction lack basic resistance to earthquake forces. In most cases this resistance can be achieved by following simple, inexpensive principles of good building construction practice. Kashmir region falls in seismic zone V, lot of earthquakes have occurred in the valley in the past. Seismologists around the world are focusing on this part of the world with the thought that mysteries will get unfolded in this part .A recent study by a seismologists Roger Bilham created tension, his studies recently created havoc when a recently headline in local daily read “Magnitude 9.0 is waiting to shake down Kashmir”. In such alarming state it is necessary to create awareness amongst masses and to find out techniques which would be worthwhile for tackling such massive destructions. This concept led me to the thought that how the old traditional structures survived the shock of the past earthquakes and my thought process stressed , focusing on the techniques involved and the revival of these structures in the modern construction , which might seem to be aesthetically pleasing but are weak in case off earthquake forces and will collapse . The seismic resistance of bamboo-frame structures is relatively high, provided the quality of materials and the construction are satisfactory. The buildings generally tend to be lightweight, especially when compared to wood, brick or stone, which helps reduce earthquake forces on the structures. The seismic performance of bamboo-frame construction is greatly enhanced by its nonstructural components .The architectural finishes and numerous non-load-bearing walls increase the amount of energy the building can dissipate during an earthquake because these additional systems absorb energy as they are damaged. The dhajji diwari style of construction was observed to exhibit a desirable seismic response, and was implemented in the older houses of Kashmir, both in the rural and urban setting. It emerged as a time-tested earthquake resistant technique, indigenously developed through repeated earthquake disasters and several generations, that too in the rural setting. Today very few buildings exist in Kashmir whose construction is based on this system entirely, long dormant periods between disastrous earthquakes probably led to abandoning robust and appropriate construction practices, in favor of newer construction technology, without any earthquake resistance. So this research paper is focused on revival of traditional earthquake resistant technique mainly DHAJJI DEWARI but making it cost effective , increasing durability and strength by replacing timber with bamboo. CONCEPT OF DHAJJI DEWARI In the ancient language of carpet weavers, the Old Farsi word ‘Dhajji’ was used to describe patchwork quilts as shown in fig 1, Because of its visual similarity the same term was applied to a traditional building technique of the Kashmir Mountains. Dhajji construction is made of highly subdivided light timber frames with masonry infill. During the 7.6 magnitude earthquake of October 2005, traditional Dhajji houses have proved to be surprisingly earthquake resistant while nearly half a million other buildings, many of them made with modern building materials, have collapsed. Mechanism of dhajji dewari In dhajji small panels are there, so there is distribution of energy. Where as in big panels the energy is concentrated. There is friction between the mud mortar and bricks which damps the energy and hence helps in resisting the earthquake. Earthquakes in Kashmir have occurred with regularity over the centuries, and the Kashmiri houses reflect an adaptation to this threat through the interlacing of heavy timber within the plane of the exterior walls of the masonry buildings. 2
  3. 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Figure 1 Old Farsi carpet dhajji on which dhajji dewari name and concept devised In Kashmir, as in most countries, wood and nails are simply too precious to be used for more than what is absolutely necessary, so masonry is the primary building material. MAKING DHAJJI DEWARI COST COMPARISON WITH TIMBER EFFICIENT AND BAMBOO PROPERTIES The cost of timber particularly in Kashmir valley led to the destruction of traditional techniques and local masonary structures thus built can prove to be disastrous because of Kashmir valley falling in seismic zone v. So replacing timber with bamboo in dhajji dewari will certainly change the mind set of people who are no longer going for this technique. The world timber demand is increasing at a rapid rate but the timber supply is depleting. It’s been found through research that bamboo can suitably replace timber and other materials in construction. Industrially treated bamboo has shown great potential for production of composite materials and components which are costeffective and can be successfully utilized for structural and non-structural applications in construction. Bamboo is one of the oldest traditional building materials used by mankind. With the advancement of science and technology and the tight supply of timber, new methods are needed for the processing of bamboo to make it more durable and more usable in terms of building materials. The behavior of breaking a wood differs clearly from the breaking conditions of bamboo. Here you don't have spontaneous break through the whole material after the tearing of single bamboo fibers like wood does. Bamboo has several unique advantages like ability to grow fast with a high yield and also it matures quickly. Additionally bamboo can be grown abundantly and that too at a lower cost which makes it more economical. 3
  4. 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Some of the advantages of bamboo over timber are as follows. • Bamboo is an environmentally friendly product. It takes only a few years for a bamboo plant to grow to maturity, while it takes decades for hardwood trees. • Bamboo is much cheaper than timber. • Tensile and compressive strength of bamboo is more than timber. • Bending and shearing strength of bamboo is more than timber. • Bamboo is extremely light weight as compared with timber. • Bamboo is extremely flexible which makes it particularly useful in earthquake-prone areas. EXPERIMENTATION AND RESULTS SHOWING COMPARISON OF BAMBOO WITH TIMBER FRAMES Frames and their arrangement To test the behavior of different bracing configurations, the three most commonly adopted bracing configurations were studied. These arrangements of the bracing systems were adopted after thorough field survey and exhaustive literature survey: Firstly testing was done with BAMBOO: The properties of frame are as under Specie of bamboo: D. STRICTUS. Diameter of frames: 4”. Height and width of frames: 5 ft. Height and width of frame was chosen as per loading frame conditions. • Some specific properties of Bamboo are as given below: Specific gravity Modulus of rupture Modulus of Elasticity Ultimate compressive stress Safe working stress in compression Safe working stress in tension Safe working stress in shear Bond stress Cost • - 0.622 - 900k g/cm2 - 1.8 x 105kg/cm2 - 824 kg/cm2 - 105 kg/cm2 - 320 kg/cm2 - 170 kg/cm2 - 5.6 kg/cm2 - 200 rs/12 ft long bamboo. The properties of wooden frames are as under: Cross section of vertical main posts: - 0.1016m × 0.1016m Cross section of bracings: - 0.1016m × 0.0508m Height of frames: 5 ft Width of frames: 5 ft The height and width of the frames was chosen as per loading frame conditions. Wood type: poplar Poison’s ratio: - 0.318 Modulus of elasticity: - 10900 KN/m2 Cost - 1200/ 10 ft ×1 ft × 1 ft long Timber 4
  5. 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME The various arrangements of BAMBOO frames are as under: Figure 2: Configuration no 1 Figure 3: Configuration no 2 Figure 4: Configuration no 3 Similarly same types of frames of timber frames were used as follows: . Figure 5: Configuration of timber frame no 1 . Figure 6: Configuration of timber frame no 2 5
  6. 6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Figure 7: Configuration of timber frame no 3 Figure 8: Iron Straps used for strengthening of joints in bamboo frames EXPERIMENTAL SET UP, INTERPRETATION OF RESULTS IN TABULATED AND GRAPHICAL FORM AND ITS COMPARISON Modifications in the experimental set up and model frames: The loop holes that were observed in the preliminary investigation had to be removed for the proper testing. Reaction from the jack was transferred to the foundation by giving inclined support to the arrangement on which jack was supported. Due to this arrangement there were no deflections in the frame and proper reaction was provided from the support, which helped in transmitting complete force from the jack to the model frame. Model frames were now fabricated from the skilled workers. The gap in the joints was minimized as far as possible, due to which there was proper truss action in the model frame. Dia of the bolts was increased from 6mm to 9mm, because there was bolt failure in the preliminary testing. TEST NO 1 & 2: The first and second test was carried on frame type 1 as shown above in fig 2 vs fig 5. The test was performed using a 200 kN jack which was operated by hydraulic pump. The deflection was measured on the top of the frame using dial gauge. 6
  7. 7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Comparison of results in tabulated form and load deflection curves are as under for configuration no 1: Load(KN) DISPLACEMENT(mm) DISPLACEMENT(mm) BAMBOO frame TIMBER frame 0 2.5 0 6.9 0 2.4 3.5 5.5 9.1 14.1 3.2 6.3 7.5 10 16.8 23.4 Failure Failure 10.25 29 Failure Load Deflection 35 30 Deflection 25 20 15 Bamboo 10 Timber 5 0 0 2.5 3.5 5.5 7.5 10 10.25 Load Curve 1: Load deflection curve at the Top. Dial Gauge 1 Observations 1. The bamboo frame resisted a load of 10.25 kn whereas timber frame resisted a load of 6.3 kn for the same DHAJJI configuration. 2. Deflection at a load of 5.5KN of timber frame was 6.3(mm), however of bamboo frame it was 14.1 mm. 3. The frame could not resist force above 6.3 kN because of the Joint failure. The joints failed and the vertical posts were pulled apart from the horizontal posts. 4. Some cracks were also caused in the posts near the joints 7
  8. 8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Figure 9: Joint failure at the top Figure 10: Vertical cracks in the post 5. Failure in the frame occurred due to rupture of bamboo at the joint. The rupture occurred at the joint which was below the joint at which loading was applied. The figure below depicts the failure Figure 11: Rupture of bamboo TEST NO 3 & 4: The third and fourth test was carried on frames as shown above in fig 4 and fig 7. The test was performed using a 200 kN jack which was operated by hydraulic pump. The deflection was measured on the top of the frame using dial gauge. Comparison of results in tabulated form and load deflection curves are as under for configuration no 2: LOAD( KN) 0 5 10 15 20 25 30 35 DISPLACEMENT(Mm) BAMBOO Frame 0 12 21 29 35 39 43 45 8 DISPLACEMENT(Mm) TIMBER Frame 0 3.6 5.6 7.2 Failure Failure Failure Failure
  9. 9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME Load vs Deflection 50 Deflection 40 30 20 bamboo 10 Timber 0 0 5 10 15 20 25 30 35 Load Curve 2 : Load deflection curve at the Top. Dial Gauge 1 Observations 1. The bamboo frame resisted a load of 35 KN whereas timber frame resisted a load of 15 KN for the same DHAJJI configuration. 2. Deflection at a load of 15 KN of timber frame was 7.2(mm), however of bamboo frame it was 29 mm 3. Various types of failures were seen, such as joint, brace and bamboo rupture. Figure 12 Joint Failure Figure 13 Brace Failure Figure 14 Bamboo Rupture 9
  10. 10. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME TEST NO 5 & 6 : The Fifth and Sixth test was carried on frames as shown above in fig 3 and fig 6. The test was performed using a 200 kN jack which was operated by hydraulic pump. The deflection was measured on the top of the frame using dial gauge. Comparison of results in tabulated form and load deflection curves are as under for configuration no 3 :LOAD(KN) DISPLACEMENT(mm) BAMBOO frame DISPLACEMENT(mm) TIMBER frame 0 0 0 2 6.2 4.8 3 12 8.2 5 18 Failure 10 23 Failure 10.25 29 Failure Load vs Deflection 35 Deflection (KN) 30 25 20 15 Bamboo 10 Timber 5 0 0 2 3 5 10 10.25 Load (KN) Curve 3 : Load deflection curve at the Top. Dial Gauge 1 Observations 1. The bamboo frame resisted a load of 10.25 KN whereas timber frame resisted a load of 3 KN for the same DHAJJI configuration. 2. Deflection at a load of 3 KN of timber frame was 8.2(mm), however of bamboo frame it was 12 mm. 10
  11. 11. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 6, November – December (2013), © IAEME CONCLUSIONS After performing tests on 6 frame types we could conclude the following from the test results and conclusion: 1. The joints are the critical locations in these traditional constructions. 2. Increasing the bracings by 100% increases the strength by 300%. 3. The strengthening of joints by Iron straps increases the load carrying capacity of the frame by 300%. 4. The best arrangement of the bracing system is configuration 2 of Bamboo Frame. 5. Bamboo as obtained from market is 6 times cheaper than timber, A single 12 ft bamboo costs only around 200 Rs, Whereas same piece of timber costs not less than 1200 Rs. 6. The maximum lateral load resisted by a Bamboo frame was of 35 KN, whereas timber frame resisted only 15 KN 7. Lateral resisting capacity of the traditional construction (dhajji dewari) replaced with bamboo proved to greater then when used with timber .After experimentation of various configurations of dhajji frames we found large variation of lateral load resisting capacity ranging from 10.25 KN to 35 KN between various frames. Configuration highly affects the performance of dhajji in earthquakes. 8. The Bamboo frame showed greater deflections, thus in case of earthquakes they will show greater dissipation of energies. 9. Initially there was more deflection with less load but when there was proper truss action frame was able to carry more load for the same deflection. 10. So replacing Timber with Bamboo is useful both in terms of cost as well as strength ACKNOWLEDGEMENTS The HOD Civil Engineering department, Proff Dr A.R.Dar (H.O.D at NIT Srinagar- Civil Engg Dept), BE Civil (Nit srinagar). M Tech (IIT Roorkee) – Structural Engineering. Phd (Bristol university) in Earthquake Engineering. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. Dhajji research project report of field visit in Pakistan by Tom Schacher, 15 september 2008. Lesson prepared by • UN Habitat (Maggie Stephenson) • SDC (Tom Schacher) Fundamentals of seismic loading on structures by Tapan Sen. National disaster management authority and united nations book on dhajji construction, “A guide book for artisans and technicians”. Safer homes, stronger communities: a handbook for reconstructing after natural disasters, published by the world bank in January 2010. “Designing and building with bamboo” Jules J.A. Janssen technical university of Eindhoven, the Netherlands. Julius Josep Antonius , a book on “bamboo in building structures”. Vidula S. Sohoni and Dr.M.R.Shiyekar, “Concrete–Steel Composite Beams of a Framed Structure for Enhancement in Earthquake Resistance”, International Journal of Civil Engineering & Technology (IJCIET), Volume 3, Issue 1, 2012, pp. 99 - 110, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316. 11

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