Tank falling through the roof

Discussion in 'General Discussions and Advice' started by NeilSmit, 7 Feb 2011.

  1. NeilSmit

    NeilSmit

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    Hi all

    I bought a new custom tank 1.6 x 0.7 x 0.7. The tank is very heavy because of the overflow design (3layers of glass at bottom and back), I would say 150kg, the tank would take about 750l, the sump about 150l, which gives a total of 1050kg.
    The only thing is, my new flat is on the second floor. Would there be a possibility of the tank being to heavy for the foundations?

    Thank you
    Neil
     
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  3. mariusmeyer

    mariusmeyer

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    I personally dont think so. To test it out you can mark that 1.6 X 0.7 on the floor, get some heavies and all jump at the same time a few times inside that space. If it holds then you are sorted :lol:
     
  4. robvdv

    robvdv

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    I had a similar problem a while back. I called in a structural engineer. He suggested I place the tank against a wall, preferably in a corner. This way the floor transfers the weight to the wall over a shorter distance.

    The floor in my case was rib and block. What's your floor made of?
     
  5. seank

    seank

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    I would find out from the Landlord/Body Corporate how the flat was built ie. Was the slab poured with the conventional system (Shutters, steel, concrete) or was it done with the "Rib and Block"system. The latter not as strong as the 1st.

    Also, make sure either of the slabs can take such an amount of weight over a 1.6 meter area-- Speak to an Structural Engineer and show the Engineer drawings of the flat
     
  6. seank

    seank

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    Even in such a case I would be worried about Shearing stresses

     
    Last edited: 7 Feb 2011
  7. Garethmur

    Garethmur

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    :lol:
     
  8. seank

    seank

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    Why you Laugh Gareth?? :biggrin:
     
  9. NeilSmit

    NeilSmit Thread Starter

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    I'm not sure how the foundation was made, I spoke to the body corp and builder, they said they will speak with the engineer and let me now... Still waiting 2 weeks later!
    Would a steal plate under the stand help to spreas the weight?
     
  10. Garethmur

    Garethmur

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    LOL because i would never have thought to ask this question... and have so many serious responses.... Im sorry may be wrong but if the flat im in cant support a lil larger than standard tank.... i dont think i would want to be living there.... what if the bath fell through the floor.... the other oaks down stairs would see me naked! LOL :lol:
     
  11. seank

    seank

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    It would spread the weight over the area if the plate is thick enough to do that, but the legs on your stand does the same.

    Some info for you on Shear stresses:

    Subjected to forces which cause it to twist, or one face to slide relative to an opposite face, a material is said to be in shear (Figure 5). Compared to tensile and compressive stress and strain, the shear forces act over an area which is in line with the forces.
    Figure 5: Shear stress applied to an object

    [​IMG]
    The force per unit area is referred to as the shear stress, denoted by the symbol τ (Greek letter tau), where
    [​IMG] Its unit is the pascal (Pa), where force is measured in newtons (N) and area in square metres.
    When shear stress is applied, there will be an angular change in dimension, just as there is a change in length when materials are under tension or compression. Shear strain, denoted by the symbol γ (Greek letter gamma), is defined by
    [​IMG] where the angular deformation, symbol φ (Greek letter phi) is expressed in radians. The last approximate equality results from the fact that the tangent of a small angle is almost the same as the angle expressed in radians. This is the reason why some texts give the radian as the unit of strain. Both shear strain and angular deformation are ratios, so have no units. However, it is not unusual for shear strain to be quoted in %, as with tensile strain.
    Shear stresses are most evident where lap joints are fastened together and forces applied to pull them apart, but are also seen when rods are twisted, or laminated boards bent.
    The shear strength of a material is the maximum stress that it can withstand in shear before failure occurs. For example, punching, cropping and guillotining all apply shear stresses of more than the maximum shear stress for that material.
    As with Hooke’s Law for tensile stress, most metals have a shear stress which is proportional to the shear strain. And in a similar way to Young’s modulus, the gradient of the graph is referred to as the shear modulus or modulus of rigidity. Again the SI unit3 for shear modulus is the pascal (Pa).
    3 You are very likely to find Young’s modulus and shear modulus quoted in psi (pounds force per square inch) or kpsi (thousands of psi). To convert to MPa, multiply the figure in kpsi by 6.89. Watch the units! You should also expect there to be very wide variations in the figures quoted, as these depend critically on alloy composition and work hardening (for metals), on purity (for ceramics) and on formulation (for polymers).
    Table 2: Shear strength and shear modulus for selected materials material shear strength MPa modulus of rigidity GPa 96% alumina 330 304 stainless steel 186 73 copper 42 44 aluminium 30 26 Sn63 solder 28 6 epoxy resin 10 – 40
     
  12. seank

    seank

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    And here is something you and Gareth :tt2: can read up on before your bath is on the neighbor's head :lol:

    [ame="http://en.wikipedia.org/wiki/Strength_of_materials"]Strength of materials - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Question_book-new.svg" class="image"><img alt="Question book-new.svg" src="http://upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png"@@AMEPARAM@@en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png[/ame]
     
  13. robvdv

    robvdv

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    You might consider hanging it off the wall, or at least Rawl-bolting it to the wall before you fill it. This way you would guarantee the force is being transferred. Make sure your stand is strong before you try this.

    I remember a large tank was put in in the Waterfront recently. It was hung from the ceiling. This was the same structural engineer I got advice from who suggested this (clever guy). So that might be another option for you.

    He also said I shouldn't worry about the weight of my tank (+/- 2 tons) on the rib and block floor. I think you're probably fine.
     
  14. NeilSmit

    NeilSmit Thread Starter

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    Would rather ask now, then being waked up by the police because my tank fell trough and killed the old tannie down stairs!
     
  15. seank

    seank

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    Rob, the problem with Rib and Block systems is not that it is not strong enough.

    Problem comes in with Contractor or should I rather say developer. I have seen this 1st hand plenty times over the last couple of years.

    What they do is, get subbies from the street to pack the rib and block systems, place 50 mm of concrete over, float it for smooth finish, and that is it.

    50mm without any reinforcing is way to weak, and the fact that the blocks are only 15mPa, would not make me sleep well at night. I am not saying every developer is doing that, but there are quite a few out there taking shortcuts to save on money- their excuse- they have done it many times and it worked before
     
  16. seank

    seank

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    And now we are not even talking about the fact that if they do use reinforcing (I suppose they would use REF 100 Mesh), that the coverage would be way too little
     
  17. NeilSmit

    NeilSmit Thread Starter

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    Thank you all for the comments. Wil have to wait then for the reply from the builder...
    I won't be able to bolt the tank to the wall because of the skirting at the bottom of the wall.
    So in a cnr would be safer than against the wall?
     
  18. HenkHugo

    HenkHugo

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    I had a look at the building codes for CPT and an appartment floor has to be able to take only 800kgs/sqm.
     
  19. NeilSmit

    NeilSmit Thread Starter

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    Thanks Henk, but would that mean if I place a 1mx2m steal plate under the tank, ill be able to go up to 1600kg?
     
  20. HenkHugo

    HenkHugo

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    no idea :D
     
  21. seank

    seank

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    As you can see here, if the load is spreaded evenly over a 1m2 area, it is not going to make a difference whether you put a plate underneith or not.

    [​IMG]
     
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