concrete area size

[roofer glasgow]

Hi can anyone help with the area size for concrete in this picture and show calculations.

( Im a student )

thanks guys

area size

• roofer glasgow
• 27 Feb 2010
• 1

 

[hotrod]

Your picture isn't clear to be honest. What does the hatched line and 14.7m relate to? What does the box with 500 in relate to?

To calculate a volume of concrete you would simply calculate the surface area first. So say the area is 5m x 14m - That would equal 70m². You would then multiple this value by the thickness required. So say the concrete needed to be 200mm thick you would calculate 70m x 0.2m - That would equal 14m³*. Hope that makes sense. If you want to clarify your figures / diagram, I'll talk you through the figures you need to use.

In reality you would also add a wastage allowance to this - say 10%.

 

[roofer glasgow]

it is a raft foundation length is 14.7m width is 3.6 thickness is 150

the 500 is too be added 463 im sure, otherwise that would be added?

 

[hotrod]

it is a raft foundation length is 14.7m width is 3.6 thickness is 150

Ok. The concrete required to pour a raft of these dimensions would calculate out thus:-

14.7 x 3.6 x 0.150 = 7.938m³

the 500 is too be added 463 im sure, otherwise that would be added?

Your diagram isn't clear. You would have to be more specific about what these figures are detailing. I would just be guessing to be honest.

hth

 

[freddiemercurystwin]

You've not made it clear how deep the slab is overall either just the depth of the bit in the middle. Hotrod's on the right track but he's forgotton about the deep bits at each side and misread 3.6 for 3.8, he should've gone to Specsavers!

 

[TicklyT]

Your question asks about the area, but which area? Surface area? Or cross-section area? Or did you really mean volume?

You will get nowhere calculating cross-section area or volume without the missing dimensions, unless the '205's on your diagram is meant to represent the depth of the projections.

One way to get to the volume is:-

1.) Convert all of your given dimensions to the same unit, preferrably Metres, so 150mm becomes 0.15 Metres, etc. etc.

2.) Divide your diagram into three rectangles and two triangles, using the dimensions you have been given (You should find the two triangles will fit together to form a fourth rectangle.). Get your ruler out, and draw the rectangles on your diagram if it helps.

3.)Calculate the area of each rectangle in square metres.

4.) Add the four areas together. This gives the cross-section area.

5.) Multiply the total area by the length to give the volume in cubic metres.

Others may chose to calculate the area of a rectangle enclosing the whole figure, and subtract the area of the void, but the method, and the result should be the same.

 

[roofer glasgow]

I have the main section - 14.7 x 3.8 x 0.150 = 7.938m³

The bottom section the depth is 300, i forgot to add that, is it:

Side A 463 x 300 (add 205 x 300) divided by 2 which is half the square x 2 as there is 2 sides

Side B 705 x 300 (add 205 x 300) divided by which is half the swaure x 2 sides

Add a and b ?? then work out the concrete required is this right?

thanks for the response guys

 

[freddiemercurystwin]

10.9544m3

 

[TicklyT]

Now we have all the info:-

3.8 * 0.15 = 0.57 (the flat slab)

0.5 * 0.3 = 0.15 (side a rectangle)

0.463 * 0.3 = 0.1389 (side b rectangle)

0.205 * 0.3 = 0.0615 (side a + side b triangles)

0.57 + 0.15 + 0.1389 + 0.0615 = 0.9204 square metres

0.9204 sq. M * 14.7 = 13.52988 cubic metres.

=13.53 cubic metres (to four significant figures).

 

[freddiemercurystwin]

Now we have all the info:-

3.8 * 0.15 = 0.57 (the flat slab)

0.5 * 0.3 = 0.15 (side a rectangle)

0.463 * 0.3 = 0.1389 (side b rectangle)

0.205 * 0.3 = 0.0615 (side a + side b triangles)

0.57 + 0.15 + 0.1389 + 0.0615 = 0.9204 square metres

0.9204 sq. M * 14.7 = 13.52988 cubic metres.

=13.53 cubic metres (to four significant figures).

Not sure how you get 13.53? I worked out the cross-sectional area (or AutcCAD did for me ) which worked out to be 0.745m2 which X by 14.7m = 10.95m3 or thereabouts

Untitled

• freddiemercurystwin
• 28 Feb 2010
• 1

or are the dimensions on my drawing wrong? This would be so much easier if OP's would just be clear and literate!

 

[hotrod]

Is this the OP's raft then Freddy?

x 14.7m long? Sweet baby Jesus, I would never have got that from his scribbled OP. Roofer glasgow can you confirm these dims are correct?

 

[freddiemercurystwin]

Aye but its not clear whether the slab overall thickness at the edges is 300 or 450mm, thats how Ticklyt ended up with 13.53m3. We need the OP to clarify!

 

[freddiemercurystwin]

Aye but its not clear whether the slab overall thickness at the edges is 300 or 450mm, thats how Ticklyt ended up with 13.53m3. We need the OP to clarify!