EXAMPLE 3.4.2. ESTIMATING WALL FOOTING FOR A WALL

A 50-m wall is to be constructed with the following specifications. Estimate the concrete components for the wall footing using class B mixture.

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There are some cases that shallow foundation affects the wall footing. In this example, footings are only embedded at 0.70m and they are 0.30m thick, which only leaves 0.40m embedment from the top of the footing to the ground. The walls are also embedded at 2 layers which totals to 0.40m embedment. This would mean that the top of the wall footing coincides with the top of the footing.

So when estimating wall footing in this case, the clear length to be considered is not the length less the column space but the length less the footing space.

                   
               
                   

With only the thickness of the wall footing detailed on the plans, the standard width would be computed as:

                   

So the volume can now be computed:

              


For class B mixture:

MIXTURE	PROPORTION	40kg	50kg	SAND	GRAVEL
		CEMENT	CEMENT
AA	1:1.5:3	12.0	9.5	0.50	1.0
A	1:2:4	9.0	7.0	0.50	1.0
B	1:2.5:5	7.5	6.0	0.50	1.0
C	1:3:6	6.0	5.0	0.50	1.0

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