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“...Construction and Building Materials 174 (2018) 701-712
ELSEVIER
Contents lists available at ScienceDirect
Construction and Building Materials
journal homepage: www.elsevier.com/locate/conbuildmat
Construction and Building
MATERIALS
■ ■
Mechanical behaviour of different type of shear band connections being used in reconstruction housing in Nepal L™
Santosh Yadav3, Yannick Sieffert3'* *, Eugenie Crete5, Florent Vieux-Champagnec, Philippe Gamier5
a Universite Grenoble Alpes, Grenoble INP, CNRS, 3SR, F-38000 Grenoble, France
bLaboratoire CRAterre, Unite de recherche AECC, £cole Nationale Superieure d’Architecture de Grenoble, Grenoble, France
cLMDC, Institut National Des Sciences Appliquees de Toulouse, Toulouse, France
HIGHLIGHTS
• The use of shear bands in masonry structures.
• Experimental approach to determine the mechanical behaviour of different materials used as shear bands.
• Reconstruction housing in Nepal.
ARTICLE INFO
ABSTRACT
Article history:
Received 10 November 2017 Received in...”
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S. Yadav et al./Construction and Building Materials 174 (2018) 701-712
the under developed and developing countries in South-East Asia. Such structures can be strengthened using several choices of materials and technique. The strengthening and retrofitting of masonry structures using modern composite materials has become quite common in developed countries [6,15] and turns out to be efficient regarding the structure stiffness and weight [ 14], as well as regarding its reversibility [20]. However, in order to increase people’s resilience to disasters on the long run, it is necessary to promote rebuilding techniques that cope with inhabitants’ empowerment, with the possibility of a self-upgradeability of houses, and with a large-scale reproducibility of the design suggested. Bearing in mind these three pillars, both traditional techniques and modern materials should be integrated, according to their adaptation to local contexts [9,19].
Seismic activities occur all over the world, but...”
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Fig- 1- Use of Horizontal timber shear band in Turkey (left) [Photograph copyright: A. Caimi] and prevention of in-plane shear crack propagation with the use of shear band (right) [Photograph copyright: Florent Vieux-ChampagneJ.
such an event, people rebuilt their houses implementing timber bands at beam level and bracings in a more systematic way. Many temples that date back to this period were not - or only slightly -damaged during 2015 earthquakes, which reinforce Ferrigni’s concept of local seismic cultures. People used their locally available resources and their own skill to build seismic resistant houses and monuments. The National Building Code regarding masonry and RC structures was published in 1994. It recommends the use of horizontal bands/ring beams at plinth, lintel, roof and gable level as a structural reinforcement. But this practice was far too often not implemented due to lack of knowledge among...”
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bands/ring beams at plinth, lintel, roof, and gable level as a structural reinforcement. But this practice was far too often not implemented due to lack of knowledge among local community and authority [23].
The design catalogue for earthquake resistance guidelines consists of the design specification for simple masonry building with minimum requirements that should be fulfilled for reconstructing buildings that could resist the damage caused by the earthquake in the near future using horizontal shear bands as shown in Fig. 3. The main objective of reconstruction housing guidelines is to translate into a concept of safer settlement using the principles of Build Back Better (BBB) [7]. This design catalogue was prepared to have more efficient approach for reconstruction work with the model design building with one or two storeys. The first design catalogue for reconstruction work has been prepared in a more conservative...”
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Clay mortar
Fig. 5. Flow chart for preparation of specimen.
For the preparation of specimens, first, the clay mortar was prepared by adding water and left it for 4-5 days to have proper swelling of clay before using in the specimen. After that, the shear band was prepared using timber and bamboo, and for the concrete shear band, the reinforcement net as per the detail provided in the DUDBC guideline was prepared. For timber shear band type 1 and bamboo, the transverse ties were connected using nails whereas for timber shear band type 2; the notch was created in the main longitudinal section and a transverse member and connected properly as shown in above Table 1. The dimension of longitudinal timber member was 900 mm x 75 mm x 45 mm, and that of the transverse member was 350 mm x 50 mm x 45 mm. Flow chart as shown in Fig. 5 outlines the steps used during the preparation of each specimen.
For the concrete shear band...”
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10.00
io.oqJ
SECTION A-A
Fig. 6. Experimental set up for cyclic shear loading.
of each range of displacement cycle was started from negative loading. The two curves for same type of shear band have similar pattern of loading and displacement thus, the reproducibility of the sample was met up to some extent however a number of specimens is required to be tested for calculation of a mean and standard deviation. Likewise, the result for Timber SB2_1 is only up to 16 mm which is due to the problem that the loading plate was about to touch the metallic plate of experimental setup while performing the test and the test was stopped beyond that limit.
For proper bonding between concrete and clay mortar layer, few pieces of stone were used while placing concrete. As shown in the Fig. 11, there is sliding behaviour observed both in positive and negative loading zone around 10 kN force which means at this level of loading...”
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707
Fig. 7. Displacement controlled loading pattern.
were not exactly the same in two specimens with concrete SB. The nature of hysteresis loop which is wide resulting in more dissipation of energy can be observed in the plot. Also, in the case of bamboo shear (Fig. 12), the hysteresis loop is thinner and comparable in both the specimen addressing the reproducibility requirement for validation of test method and results obtained.
While making a comparison between timber shear band type 1 and 2 as shown in Fig. 13, SB type 1 has narrow hysteresis loop as compared to type 2. The reason could be due to the connection of transverse ties using a nail in the case of type 1 which is easily bent and shifted with loading. Similarly, the curve with type 1 is symmetric which could be due to the equal force needed for bending of the nail connection (Fig. 14) in both direction allowing similar displacement whereas with type 2, the...”
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Fig. 10. Hysteresis curve for timber shear band type 2.
timber is lower than in concrete and so is the nature for dissipation of energy. The reason for concrete shear band dissipating more energy could be the more surface area is in contact with the clay layer creating a more frictional loss of energy. In case of bamboo, there is sudden sliding behaviour observed at low shearing load and the hysteresis loop is also thinner as compared to timber shear band as shown in Fig. 16.
4.2. Dissipation of energy
One of the use of shear band is to limit the propagation of a crack in the wall, confine all the wall together and dissipate energy by sliding friction caused during seismic action. For this purpose, the amount of energy dissipated by each cycle upon particular displacement was measured from the previous hysteresis loop curve using OriginPro 2017 software (http://www.originlab.com/2017) and taking the average between...”
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Displacement (in mm)
Fig. 13. Comparison between timber Shear Band Type 1 & 2.
Fig. 14. Bending of nail connection in timber SB type 1 specimen.
limit and maximum energy dissipated was obtained (Table 2) from the hysteresis loop as explained earlier. Similarly, the maximum load carried by each of the specimen while loading in both directions were noted and shear stress was calculated and tabulated in Table 3 below. As observed in the tabular value, the average stiffness and the plastic energy dissipated (which could be use as information about ductility behaviour) of TSB type 2 and concrete SB are comparable, and that of bamboo is the least which means a small amount of force can make large displacement with bamboo used as a shear band. These values of stiffness and energy dissipated can be used in development and validation of numerical
simulation code for carrying out the parametric analysis for shear band using...”
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. 15. Hysteresis curve comparison of concrete SB with timber SBl_2_dry.
Force (in kN) 3 Force (in kN)
- Bamboo SB 1
- Timber SB 1-2
0 Hysteresis curve comparison
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-25 -20 -15 -10 -5 0 5 10 15 20 25
Displacement (in mm)
Fig. 16. Hysteresis curve comparison of bamboo SB with timber SBl_2_dry.
5. Conclusion and recommendation
5.3. Conclusions
(1) Most of the masonry houses built in rural part of Nepal did not have seismic shear band even though it was already mentioned in the national building code of Nepal which highlights the lack of proper education and implementation of law resulting in huge damage of life and property during Gorkha Earthquake 2015. People started reconstruction works by themselves by implementing seismic shear bands, but due to lack of proper supervision by a trained person, they are not always able to make the shear band correctly.
(2) Regarding the shear bands, various materials are mentioned...”
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Table 2
Effective stiffness against sliding, energy dissipated.
S. No. Name of specimens Elastic Effective Stiffness, k (N/m) Energy dissipated
Force, kN Displacement, mm Elastic, l
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References
[1] A.S. Arya, T. Boen, Y. Ishiyama, Guidelines for Earthquake Resistant Non-Engineered Construction, UNESCO, Paris, France, 2013.
[2] J. Bothara, S. Brzev, A Tutorial: Improving the Seismic Performance of Stone Masonry Buildings, 2011.
[3] Bureau of Indian Standard, IS 1893-1984 Criteria for Earthquake Resistant Design of Structures, 2405 §, 1986, India.
[4] Bureau of Indian Standard, Code of Practice for Design Loads (Other Than Earthquake) for Buildings and Structures, 875 BIS §, 1989, India.
[5] Bureau of Indian Standard. Recommended Guidelines for Concrete Mix Design, 1999, India.
[6] T. Choudhury, G. Milani, H.B. Kaushik, Comprehensive numerical approaches for the design and safety assessment of masonry buildings retrofitted with steel bands in developing countries: the case of India, Constr. Build. Mater. 85 (2015)227-246, https://doi.Org/10.1016/j.conbuildmat.2015.02.082.
[7] DUDBC, Design Catalogue...”
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