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Calculating concrete needed for wedge shape?

  • 03-06-2020 4:37pm
    #1
    Danye
    Registered Users Posts: 2,113 ✭✭✭


    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 😊


Comments

  • #2
    Padre_Pio
    Registered Users Posts: 4,894 ✭✭✭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?


  • #3
    Danye
    Registered Users Posts: 2,113 ✭✭✭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?


  • #4
    Padre_Pio
    Registered Users Posts: 4,894 ✭✭✭Padre_Pio


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

    Which is twice mine.

    LxWxH /2


  • #5
    salmocab
    Registered Users Posts: 11,282 ✭✭✭✭salmocab


    Padre_Pio wrote: »
    Which is twice mine.

    LxWxH /2

    (LxWxH) x .75?


  • #6
    [Deleted User]
    Posts: 7,499 ✭✭✭ [Deleted User]


    Work it out as box and half it.


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  • #7
    salmocab
    Registered Users Posts: 11,282 ✭✭✭✭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


  • #8
    d.pop
    Registered Users Posts: 271 ✭✭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


  • #9
    Bass Reeves
    Registered Users Posts: 18,140 ✭✭✭✭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

    Slava Ukrainii



  • #10
    Padre_Pio
    Registered Users Posts: 4,894 ✭✭✭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.


  • #11
    Danye
    Registered Users Posts: 2,113 ✭✭✭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.


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  • #12
    jack of all
    Registered Users Posts: 2,361 ✭✭✭jack of all


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


  • #13
    Bass Reeves
    Registered Users Posts: 18,140 ✭✭✭✭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.

    Slava Ukrainii



  • #14
    Bass Reeves
    Registered Users Posts: 18,140 ✭✭✭✭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

    Slava Ukrainii



  • #15
    Danye
    Registered Users Posts: 2,113 ✭✭✭Danye


    Thank you all for your input. Really appreciate it.


  • #16
    Mwalimu
    Registered Users Posts: 42 ✭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


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