Calculating concrete needed for wedge shape?

Danye

Hi guys,

My brain is stuck and I’m looking for help if you can?

I’ve an area I need to concrete and I’m trying to calculate exactly the volume I need.

It’s 150mm deep at its highest falling down to 75mm at its lowest. And it’s 3.870m long x 2.960m wide. How do I figure out the volume?

I know it’s probably basic and simple but I can’t work it out????

Thanks 😊

Padre_Pio

Danye wrote: »

Hi guys,

My brain is stuck and I’m looking for help if you can?

I’ve an area I need to concrete and I’m trying to calculate exactly the volume I need.

It’s 150mm deep at its highest falling down to 75mm at its lowest. And it’s 3.870m long x 2.960m wide. How do I figure out the volume?

I know it’s probably basic and simple but I can’t work it out????

Thanks ��

Forget about the depth change. Make it 150mm and you'll have a little extra as a safety factor.

0.86m cube?

Danye

Padre_Pio wrote: »

Forget about the depth change. Make it 150mm and you'll have a little extra as a safety factor.

0.86m cube?

Even by using the 150mm depth I worked it out at approx 1.7m3?

Padre_Pio

Danye wrote: »

Even by using the 150mm depth I worked it out at approx 1.7m3?

Which is twice mine.

LxWxH /2

salmocab

Padre_Pio wrote: »

Which is twice mine.

LxWxH /2

(LxWxH) x .75?

Work it out as box and half it.

salmocab

BrownFinger wrote: »

Work it out as box and half it.

Think only a quarter is gone or the wedge so 3/4 of the box

d.pop

Convert it to a rectangle (.075x 3.870x 2.960) = 0.86m3 with a triangle on top 3.870x.5 x .075 x 2.960 = 0.429. Total concrete = 1.289m3

Bass Reeves

Handiest way is multiply the length by the width which is3.87*2.96=11.46.

To allow for the different depth you find the middle point between 75mm and 150mm=112.5mm or 0.1125m.

You now multiply 11.45m by 0.1125m=1.289 cubic metres.

Generally you add a fraction for settlement when vibrating/tapping. However there is nothing worse than having 2-3 barrows to get rid of. You will need to order 1.4 cubic metres of concrete

Padre_Pio

Bass Reeves wrote: »

Handiest way is multiply the length by the width which is3.87*2.96=11.46.

To allow for the different depth you find the middle point between 75mm and 150mm=112.5mm or 0.1125m.

You now multiply 11.45m by 0.1125m=1.289 cubic metres.

Generally you add a fraction for settlement when vibrating/tapping. However there is nothing worse than having 2-3 barrows to get rid of. You will need to order 1.4 cubic metres of concrete

Length by width by average height gives you a cuboid, not a wedge.

Danye

Bass Reeves wrote: »

Handiest way is multiply the length by the width which is3.87*2.96=11.46.

To allow for the different depth you find the middle point between 75mm and 150mm=112.5mm or 0.1125m.

You now multiply 11.45m by 0.1125m=1.289 cubic metres.

Generally you add a fraction for settlement when vibrating/tapping. However there is nothing worse than having 2-3 barrows to get rid of. You will need to order 1.4 cubic metres of concrete

Thanks very much.

jack of all

Bass Reeves for the win! 1.28m3 and add 10% for those voids/ uneven base and settlement gives you 1.4m3.

Bass Reeves

Padre_Pio wrote: »

Length by width by average height gives you a cuboid, not a wedge.

Technically it not a wedge it a cube on top of a wedge. I just converted it to a complete cube.

Bass Reeves

jack of all wrote: »

Bass Reeves for the win! 1.28m3 and add 10% for those voids/ uneven base and settlement gives you 1.4m3.

TBF d.pop got it ahead of me but did not allow for settlement/uneven base. Mine you I have kept it tight at less than 10%. Depending on the situation only thing worse than having to find a place for extra concrete is being short of it. There is about 25 barrows in a cubic meter. So even 0.1cubic meter could be 2-3barrows. As well a lot of concrete companies will allow a small bit extra on jobs

Danye

Thank you all for your input. Really appreciate it.

Mwalimu

Bass Reeves wrote: »

Handiest way is multiply the length by the width which is3.87*2.96=11.46.

To allow for the different depth you find the middle point between 75mm and 150mm=112.5mm or 0.1125m.

You now multiply 11.45m by 0.1125m=1.289 cubic metres.

Generally you add a fraction for settlement when vibrating/tapping. However there is nothing worse than having 2-3 barrows to get rid of. You will need to order 1.4 cubic metres of concrete

Same idea as treating the cross-section like a trapezium, get its area and multiply by length. Ans 1.2887 cubic metres