Using the unit method, calculate the stretch-out-length of the concrete footings
ID: 2312740 • Letter: U
Question
Using the unit method, calculate the stretch-out-length of the concrete footings and foundation walls on the attached drawing. Calculate the following: (25) The volume of concrete required for the footings. Add 6% waste. The volume of concrete required for the walls. Add 6% waste The volume of concrete required for the concrete slab. Add 5% waste. The formwork required for the footings. The formwork required for the foundation walls All reinforcing as indicated for the footings and foundation walls. 18 750 250- -15 M VERT @ 300%. 1200 I5M DoWELS EACH WAY 8800 boo l 150 350 102 P5M@ 300 olc 1200 5-1SMExplanation / Answer
Divide the walls into Long walls and Short walls
1.Length of Long wall as given in Drawing = 18.7 meter
2.Length of Short wall=8.80-(2 x width of wall) = 8.80- (2 x 0.25)= 8.30 meter
a.therefore volume of concrete required for footing = Total length of wall x width of footing x depth of footing
Total lenth of Wall= 2 x (18.7+8.3) = 54 meter
Volume of concrete for footing = 54 m x 1.2m x 0.35 m = 22.68 m3
adding 6 percentage for wastage , Total volume of concrete for footing = 22.68+ (.06 x 22.68) = 22.04 m3
b. volume of concrete required for walls = Total length of Wall x height of wall x widthof wall= 54 m x 1.2 m x .25 m = 16.2m3
adding 6 percentage for wastage , Total volume of concrete for Wall = 16.2+(.06x16.2)= 17.17 m3
c.Volume of concrete for slab = Lenth of slab X width of slab X thickness of slab
= 18.75m x 8.8 m x 0.15 m = 24.75 m3
adding 5 percentage for wastage , Total volume of concrete for Slab = 24.75+(0.05 x 24.75)= 24.987 m3
I calculated the above assuming volume of reinforcement negligible. If youwant answer by deduction of area of reinforcement, please specify
d. Formwork reqd for footing = Length of Footing x depth of footing x 2No = 54m x 0.35m x2 No
= 37.8 m2
e. Formwork reqd for walls = Length of wall x height of wall x 2 No= 54m x 1.2m x 2 No = 129.6 m2
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