BMTPC

RANDOM RUBBLE STONE FOUNDATION IN MUD MORTAR
System Components	Initial Cost Structure
	· Local Economy component = 51 % · Foundation in RRM in mud mortar of 450 x 450mm over 600 x 600 footing in granite stone
DESIGN EXAMPLE : Foundation for a single storey Building
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) = 125 KN/sqm W (weight of soil) = 18 KN/sqm Angle of repose of the soil = 30 = 125/18x0.111= 0.77 m. Assuming bearing capacity of soil = 200 Km/sqm Width required = 125/200 = 0.625m Thus provide a foundation width = 76 cm and depth 77 cm
Critical Factors 1. Quality of soil 2. Width and stepping of foundation 3. Providing through stones 4. Protection from water 5. Inter‐locking at corners	Tools Used 1. Trowels 2. Plumb bob 3. Thread 4. Pans 5. Shovel 6. Pick axes 7. Baskets
DO’S	DON’T’S
1. Soil should have medium plasticity 2. Thorough stones should be provided 3. Natural bed of stone should be always Perpendicular to the loading.	1. Sand and clay should be used for mortar 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