# Math Help - Help determining area and m3 required.

1. ## Help determining area and m3 required.

Hi

Find attached an image of a solid piece of concrete sidewalk, disregard the colour variation, think of this diagram as ONE solid piece of concrete. I'm trying to determine how many linear metres I can pour of concrete sidewalk with 11m3 of concrete. I need to understand how you arrived at the quantity. Please be very detailed, I require these types of calculations in my daily job.

2. ## Re: Help determining area and m3 required.

First thing to do is find the area of the figure(s).

What do you get?

3. ## Re: Help determining area and m3 required.

Thanks..

I get 0.34875m2 area total.

4. ## Re: Help determining area and m3 required.

Originally Posted by bronte
Thanks..

I get 0.34875m2 area total.
your area calculation is correct, however ...

What is the perspective of this sketch? is this a view from above?

Also, I question the validity of your measurements ... a sidewalk that is 150 mm = 15 cm in width?

Finally, what exactly are you trying to determine?

5. ## Re: Help determining area and m3 required.

Area * length ( m^2 * m )= m^3. You have 11 m^3. Solve the equation

bjh

6. ## Re: Help determining area and m3 required.

Originally Posted by skeeter
your area calculation is correct, however ...

What is the perspective of this sketch? is this a view from above?

Also, I question the validity of your measurements ... a sidewalk that is 150 mm = 15 cm in width?

Finally, what exactly are you trying to determine?
The dimensions are correct. The drawing is a side view of a monolithic sidewalk.

The problem to solve is.....I need to determine how much monolithic (length) sidewalk I can pour with 11m3 of concrete.

7. ## Re: Help determining area and m3 required.

Do I divide the 11m3 into .34875m2 = 31.70m which would be the length of sidewalk I can pour with 11m3 of concrete?

8. ## Re: Help determining area and m3 required.

Hi bronte,
Area * length = volume 0. 34875 * L = 11.3 L= ?
A comment on your crosssection of a foundation and a side walk- the elevation of the sw would be shown lower than the foundation.

bjh

9. ## Re: Help determining area and m3 required.

Originally Posted by bjhopper
Hi bronte,
Area * length = volume 0. 34875 * L = 11.3 L= ?
A comment on your crosssection of a foundation and a side walk- the elevation of the sw would be shown lower than the foundation.
Thank you for your help but I'm still no closer understanding this problem.

I'll begin with the cross section of sidewalk. The drawing is correct 'monolithic sidewalk' is sidewalk and curb poured as one. The 450-250-350mm section is the curb and the 1.5m x 150mm is the flat walk--this represents one solid piece of concrete when cured.

My boss walks up to me and said " Bob, I have 11m3 of concrete on its way and I need you to instruct the concrete formers to prepare enough monolithic sidewalk forming so all 11m3 is used, none wasted.

Now I know the dimensions in the drawing I provided, standard stuff, what I need to find out is how long do I instruct the conc formers to build the forms in linear meters. This is important because the cost of the concrete and time constraints in off loading the concrete I need to have an uninterrupted conc pour and secondly, if my crew consists of 11 men and equipment and I need to stop the pour because the forms are not long enough, I run the risk of the concrete going bad (yes concrete will go bad) and 11 men at $30.00 per hour standing around would not make my boss very happy. So the question still remains; using the provided dimensions and with 11m3 of concrete on its way; how long are the forms required to be built to accept the 11m3. I have the area as .34875m2 I then divided .34875 by 11 for a total of 31.54 L/m of form required to accept the volume (11m3) of concrete. I'm I close or should I begin all over again? Thanks.. 10. ## Re: Help determining area and m3 required. Originally Posted by bronte Thank you for your help but I'm still no closer understanding this problem. I'll begin with the cross section of sidewalk. The drawing is correct 'monolithic sidewalk' is sidewalk and curb poured as one. The 450-250-350mm section is the curb and the 1.5m x 150mm is the flat walk--this represents one solid piece of concrete when cured. My boss walks up to me and said " Bob, I have 11m3 of concrete on its way and I need you to instruct the concrete formers to prepare enough monolithic sidewalk forming so all 11m3 is used, none wasted. Now I know the dimensions in the drawing I provided, standard stuff, what I need to find out is how long do I instruct the conc formers to build the forms in linear meters. This is important because the cost of the concrete and time constraints in off loading the concrete I need to have an uninterrupted conc pour and secondly, if my crew consists of 11 men and equipment and I need to stop the pour because the forms are not long enough, I run the risk of the concrete going bad (yes concrete will go bad) and 11 men at$30.00 per hour standing around would not make my boss very happy.

So the question still remains; using the provided dimensions and with 11m3 of concrete on its way; how long are the forms required to be built to accept the 11m3.

I have the area as .34875m2
I then divided .34875 by 11 for a total of 31.54 L/m of form required to accept the volume (11m3) of concrete.

I'm I close or should I begin all over again?

Thanks..
You say you calculated that the cross-section area is 0.34875m2 and skeeter confirmed that (I didn't check myself). Now yoi have 11 cubic meters of concrete.

Volume is "area times length" so 0.34875*length= 11. Actually you divide 11 by 0.34875 rather than 0.34875 by 11 but that is what you really did since you get what I got. My calculator says that length= 11/0.34875= 31.5 m (approximately).

11. ## Re: Help determining area and m3 required.

You have the math answer now but wouldn't you build 30 m of forming

bjh

12. ## Re: Help determining area and m3 required.

Originally Posted by bjhopper
You have the math answer now but wouldn't you build 30 m of forming

bjh
Now understanding how this calculation works I would feel comfortable with a form 32 meters in length.