What quantity

What volume of concrete should be ordered for the foundations of a rectangular family house with dimensions of 15 m × 12.6 m, using permanent formwork? The depth of the foundation formed by permanent formwork is set at 80 cm. The concrete used constitutes 80% of the volume of the block.

Permanent formwork block dimensions: 500 × 300 × 200 mm.

Final Answer:

V =  10.4832 m³

Step-by-step explanation:

$$\begin{gathered} a=15\text{m} \\ b=12.6\text{m} \\ c=80\text{cm}\to \text{m}=80:100\text{m}=0.8\text{m} \\ d=300\text{mm}\to \text{m}=300:1000\text{m}=0.3\text{m} \\ r=80\%=\frac{80}{100}=\frac{4}{5}=0.8 \\ o=2\cdot a+2\cdot b-2\cdot d=2\cdot 15+2\cdot 12.6-2\cdot 0.3=\frac{273}{5}=54.6\text{m} \\ {V}_1=o\cdot d\cdot c=54.6\cdot 0.3\cdot 0.8=\frac{1638}{125}=13.104{\text{m}}^2 \\ V=r\cdot V_1=0.8\cdot 13.104=10.4832{\text{m}}^3 \end{gathered}$$

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