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RANDOM RUBBLE STONE FOUNDATION IN CEMENT MORTAR (1:8)
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System Components
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Initial Cost Structure
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· Local Economy component = 30 %
· Foundation in cement mortar 1:8 of 450 x 450mm over 600 x 600 footing in hard stone (granite) from quarry
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DESIGN EXAMPLE : Foundation for a single storey Building
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Maximum width required = 2 x width of the wall + 0. 3m
(Assuming 23cm thick brick wall)= 2 x 0.23 + 0.3 m. = 0.76m.
Minimum depth required =
Assuming P
Safe permissible pressure on base = 175 KN/sqm
W (weight of soil) = 18 KN/sqm
Angle of repose of the soil = 30 = 175/18x0.111 = 1 m.
Assuming bearing capacity of soil= 200 Km/sqm
Width required = 175/200 = 0.85m
Thus provide a foundation width = 85 cm and depth 100 cm
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Critical Factors
1. Workability and strength of stone
2. Width and stepping of foundation
3. Providing through stones
4. Grading of sand
5. Inter‐locking at corners
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Tools Used
1. Trowels 5. Shovel
2. Plumb bob 6. Pick axes
3. Thread 7. Baskets
4. Pans 8. Hammer (Big & small)
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DO’S
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DON’T’S
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1. Curing should be done for seven days
2. Thorough stones should be provided
3. Natural bed of stone should be always perpendicular to the loading.
4. Mortar should be used within 30 minutes of adding water to the mix
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1. Find sand should not be used for masonry
2. Rounded stone should not be used for masonary
3. Masonry should not be allowed to dry out quickly
4. Bonding of the wall should not be filled with small stone pieces
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Construction Process
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