### Calculating Earth work excavation for a compound wall./ Estimating & costing of a compound wall ( part 1 ).

Let us now estimate the cost of a compound wall for a 30' × 40' site with a 10' gate as shown below.

Let us build this wall in a concrete block, with the plinth beam and columns as shown in the drawing.

We have provided the columns at 10 ft. c/c.

The number of columns required

= site perimeter ÷ c /c column distance

=[ ( 40ft.× 2 nos.) +( 30 ft. × 2nos.)] ÷ 10 ft.

= 140 ft.÷10 ft.

= 14 nos. ( as shown below.)

1. Earthwork excavation for the compound wall :

Excavation for the footing

The number of excavation pit required for the column footing = 14 nos.

Let us provide  1.5' × 1.5' size footings, and the dimension of the pit to accommodate these footings shall be  2ft. × 2ft.× 2.5 ft. as shown in the drawing (below ).

The total volume of excavation for footing

= 2ft. × 2ft. × 2.5 ft. × 14 nos.

= 140 cu.ft.

Excavation for the plinth beam

Let us excavate 4" extra on either side of the plinth beam for formwork removal as shown in the drawing.

The volume of excavation for the plinth beam

=[ perimeter of site  - ( no. of footings × footing excavation width.)] × plinth excavation width × plinth excavation depth

= [140 ft. - (14 nos. × 2 ft.)] × 1.416 ft. × 0.9166 ft.

=  112 ft. × 1.416 ft. × 0.9166 ft.

=  145.365 cu ft.

The total earthwork excavation for compound wall

= footing excavation + plinth excavation

= 140 cu ft + 145.365 cu ft.

=  285.365 cu ft.