Engineer help needed...plz help prevent my buiding collapsing

S

snadaud

New member
Hi to you all friendly, helpful, (and hopefully competent ;)), structural engineers out there...

I have a weight problem... well actually my dream tank has a weight problem and any help and advice you can contribute to transforming this potential disaster into a success will be greatly appreciated !!

I am planning a large tank, about 1.5m wide x 2.3m long. Not sure about the height yet...

My first problem is I live on the 8th floor...

My second problem is I live in China and haven't found anybody able to tell me accurately how much load/m2 the building can safely stand... It is made of steel reinforced concrete and the walls are 20cm thick. I assume the flooring too but I can't get a solid confirmation of that.

Anyway, i have been told that the building should be ok with up to 600Kg/m2. Does it sound reasonnable to you ?

In order to be able to get as much height as possible in the tank, I plan on spreading the load on a larger surface.

I am thinking of making a larger square base (abt. +30 cm on 3 sides) using some I-beam perpendicular to each others and pouring a 10cm slab of concrete on top. Of course, in my calculation I would take into account the weight of the slab and stand. Is this reasonning correct or would the tank weigh heavier just under its own footprint and not be distributed uniformly on the surface of the slab?

The tank would be parrallell to/along a load bearing wall, and I am thinking on inserting the I-beam perpendicular to this wall inside the wall itself to try and spread part of the weight to the load bearing wall instead of my floor. Is it a good idea or would this actually create a stress point with more weight on the ends of the beams that are not in the wall ?

Finally I have a feeling that the tank would put less stress on the floor by having its length (2.3m) parrallel to and along the load bearing wall. However I am also considering putting it with its length perpendicular to the wall but i'm afraid it will put even more stress on my floor. Is this purely superstition or actually a valid reasonment ? (it probably would put more stress on my floor anyway, because in this case it would free up some space on the sides of the tank and I could increase its width to more than the currently planned 1.5m ;))

I thank you in advance for any help you will be able to give me, since the "knowledge" I'm working on is nothing more than uneducated guesses on my part and faith in my good luck

:rolleyes:

I would really hate for my tank and its stand to get all the way to the groundfloor through my neighbours appartments...:hmm4: :hmm4: :hmm4:
 
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Come on...a month...253 views...not a single reply ?!
:sad2:
ok i wave the competent bit :)
anybody can help me now ?
Thanks in advance
 
I would first say, your posting on a american forum, so use american units instead of meters & centi meters. Use inches and feet. You would be better off with responses, that way people dont have to calculate what meters is to feet and inches, etc. Just my 2 cents. And if you are in a steel & concrete reinforced high rise building I think a 1000gallon tank would be fine, just my guess and 2cents. Good luck either way.
 
Not an engineer but I personally think you have to sacrifice the width of the tank. I am currently living in a flat too, on the 11th floor and I have a 4x2x2ft tank with a 3ft sump but a longer cabinet at 6ft length just to distribute the weight of the tank. Personally have seen someone else tank that is 3ft in width and that might be the limit I presumed. What I was advised before setting up a tank is that to place the setup very,very close to the wall, right next to it actually. The wall should be the beam of the building whereby no renovation should be done to that wall or even to the wall below your apartment. The supporting structure of the whole building. If you have that location, that is the place for the tank.

It would be better if you could use the whole length of that wall and use both corner of the wall too. You might have a 6ft tank for your use but if the cabinet or the tank support could reach till both corner end of the wall, the setup would be well supported. I had mine placed near a corner of my flat.As for height of the tank, I believe 2ft is enough, any deeper, you'll have problem reaching in.


On a personal note, I wouldn't advise getting a too large a setup that may cause structural problem. If the floor should giveway, you might hurt the resident that is living 1 floor below yours. Also, your building property will not be attractive to potential buyer if they know that the building had a structural problem in the past. This is a hobby for you to enjoy! Not to hurt another person.


Hope this 2cts helps!
:)
 
finding how wide the beams are and which direction they run, and where's a load bearing wall on the floor beneath you will all go a long way to getting help. Just saying "will the floor handle it" is not enough information.

Don't want to sound offensive here, but not knowing what building codes are in China and assuming they are way less stringent than in the US would make me worry about putting a tank that size of any floor above ground level.
 
600kg/m2 sounds reasonable to me. Again, this is where finding out the actual structure of supports in the building would help tremendously.

If that 600kg/m2 is accurate you should be good to go. You're talking about roughly 11 square feet per 1 square meter. And one cubic foot of water weighs about 60 lbs. So, round up a little bit and say 700lbs of weight per square meter for every 1 foot of depth in your tank. Two feet of depth would put you at 1,400 lbs per square meter, or 636kg/m2.

Personally, I would limit your depth to about .5 meters to stay under that 600kg/m2 mark unless you can find out more about the building's actual specs. If you make the base wider like you mentioned you might be able to bump the height up a little, but again, I would be leery of doing this until you find out the design of the floor's support.
 
I've been told if you put it next to a bearing wall you should be alright. If you calculate the weight of a refridgerator per sq whatever the weight per inch is about the same. Do you know your neighbors downstairs well?
 
Anyway, i have been told that the building should be ok with up to 600Kg/m2. Does it sound reasonnable to you ?
Click to expand...

The safe working load will not be based on m2. Based on your comment 2.0 m2 can hold 1200 kg, however 2.0 m2 may support less weight.

The determined safe load will also depend on where it is placed, eg: next to walls, or above floor support columns etc.

You need to find out the maximum permissible load on the floor in the position you need.

For your information

Based on your dimensions and 0.75m deep, the tank would be transferring approximately 2600 kg of weight to the floor, not including the weight of the tank / support stand / tank equipment and sand / live rock

At 0.5m deep the load would be approximately 1800 kg without the weight of the tank and other stuff mentioned above

Other tank dimensions and water weights:

1.0m x 1.8m x 0.5m or 1.0m x 1.5m x 0.6m: Load = 900 kg

1.0m x 1.5m x 0.4m: Load = 600 kg

0.8m x 1.2m x 0.4m: Load = 400 kg

You need to have ample safety factor to allow for your fuge, equipment, sand, liverock etc.

In any case, I would get everything checked by an engineer in China.... for insurance purposes etc..... hey, didn't a big pink shopping mall sadly collapse over there in the past ? Just because someone has said the floor can cope with "whatever" this should be verified by engineers first.

Hope this helps !
 
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Wow !!! Thank you guys !! :D

I never expected so many answers at once after such a long silence :rollface:

gregmoeck - If the worst that can happen a slight cave-in I would count myself lucky...However I haven't met the neighbour who lives under my appartment and I'd rather meet him in other circumstances than discussing the cave-in of his ceiling and what I'm going to do to fix it...

BILLYO382 - Good point...so for those of you metrically challenged that would be 4'11"wide x 7'6" long ;)

bfg - The way I intend to set up the tank is as you say, along the load bearing wall. However the wall is in the middle of the room and I can't go all the way to the corners. By the way why do you think 3' is the max width ? Don't worry, I don't forget that this is a hobby and I don't plan on endangering anybody's health or life to satisfy it...I would even less enjoy meeting my neighbour in a hospital than in his living room discussing his ceiling cave-in...

sfsuphysics - The beams and load bearing walls are 20cm or 8" wide. Concerning the load-bearing wall position : "The tank would be parrallell to/along a load bearing wall, and I am thinking on inserting the I-beam perpendicular to this wall inside the wall itself to try and spread part of the weight to the load bearing wall instead of my floor. Is it a good idea or would this actually create a stress point with more weight on the ends of the beams that are not in the wall ?" Since there's a load bearing wall along the tank, I guess it's safe to assume that there is a load bearing wall in the exact same spot on every floor under my tank...What would be the point of having a load bearing wall standing on nothing ? Am I wrong in assuming this ?

atzak - Just bought the appartment, have just started renovating it but haven't moved in yet...moving to the ground floor is not an option at this time.

woz9683 - Actually I was hoping to be able to get abt 70cm water height (including the sand). This would be 700Kg/m2 of water weight, and that was part of the reason I was thinking of making the stand a bit larger to spread the weight.

moumda - I have been playing with lines of reasonning similar to your fridge comparison...like : I'm 80 Kg, so if I stand on the toes of 1 foot only, the load /m2 is much higher than 600kg...:-) Another one I just realized since I have started taking down walls this week is that some non load-bearing walls are made of brick. Since they are not load bearing it is conceivable that the neighbours on some floors below have taken them down. That would mean that the concrete slab of the floor should be able to bear the full weight of the wall. I have weighted and measured the brick and the load/m2 is over 3 tons or 6600 Lbs... Makes me feel a bit safer but I'm not sure this reasonment is right...

chrispc66 - The fuge would not be under the tank, but in a dedicated fish room about 4 meters away. I would love to find an engineer to come and inspect the place, but the trouble is that they are not very interested in giving advice to build a fish tank when they can take part in building some of the highest buildings in the world...Also, besides not being interesting/prestigious they don't want to take the responsibility...I saw that documentary about the pink shopping mall and I really don't hope to replicate that..By the way I think it was in Korea
 
Cheers snadaud,

I am an engineer, and would be happy to offer some guidance , if you can provide accurate load bearing data, tank dimensions, construction materials, additional equipment and stock etc.

In any case, you should consult the local council for some free advice. They would have engineering drawings on record.

If your floor cannot support the weight you need, you may be able to use the external walls to bear some load, by attaching your stand to the wall at the rear using chem anchors.

Also bear in mind, that point loading is far more prone to failure than load distributed over a wider area.

Good luck with your project
 
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Thanks chrispc66 !
Unfortunately my building has been built about 9 years ago and at that time there was a distinction between buildings which were ok for foreigners to buy and those reserved to Chinese nationals. Thanks to that, there were 2 different departments to keep the drawing relating to these building, one for foreign ok bldg and one for chinese bldg.
Since about 6 or 7 years ago that distinction does not exist anymore, and the department holding the foreigner's bldg plans has also disappeared...Unfortunately it seems that many drawing have been misplaced at that time, including those of my building...:(
I am afraid that the only free advice I would get by visiting the local council would be a quick "don't do it" without them even taking a minute to ponder my question...:rolleye1:
Is my reasonment in my answer below concerning the weight of my non load bearing brick wall correct and can it be applied to a fish tank ?
Also, if the weight of my tank turned out to be too much for my floor, would the problems happen just around the tiome when I fill the tank, or could the floor get slowly damaged other a long period of time and then suddenly fail after a few months ?
Thanks in advance !! :D
 
Sounds to me like it would be fine. A building that size should be able to hold almost anything. I'm setting up that size tank now on a wood floor, and its not going to require that much additional support. Actually it doesn't but I like to over build so im beefing it up.

I would do it, and get insurance. B/c you need the insurance anyways. if it pops, it wont matter if it was the floor or not, its gonna cost alot, better be safe.

As far as metric/inches is concerned, if you can't read metric, you don't have the knowledge to begin answering this question.
 
No problem snadaud,

There are many variables with your problem. The thickness of the slab is not the governing factor for load capacity. Type of slab, amount and diameter of reinforcement bars etc.

I suspect the slab was poured over reinforcement bar bundles and within a forming system. Lower density and porosity normally result. This method of slab construction is suitable for most domestic dwellings. Their strength relies on thickness. Often cracks appear, however do not lead to failure due to the reinforcement bundle. Not often are items over 2.6 tonnes in weight placed in these dwellings though...

The ideal scenario for your floor is a prestressed concrete slab, meaning it is reinforced with reinforcement bars that are placed in tensile stress just below their yield point prior to concrete pouring. Upon setting, the tensile stress is removed, and the bars are under a compressive stress, ( trying to return to a relaxed state, however cannot - hence compressive forces are induced ). This in effect "holds" the slab together and increases the yield point of the reinforcement bars themselves. Much more to this, but not the place to discuss.

Slabs of this type resist far higher loads and stresses in comparison to the other slab types described above.

In summary..... there are too many variables to accurately predict the outcome if 2.6 tonnes of weight are placed on your floor. Outcomes could include:

Tank falls through the floor upon filling..... Not good :eek2:
The floor creeps over time until failure.... Not good :mad:
Nothing happens... good outcome :rollface:

Ways forward.... Meet with your neighbours and ask them about the types of furnishings they have. Look for things like large bookshelves, aquariums obviously, free standing cupboards full of gear, and anything with obvious weight situated in areas where you plan to site your aquarium.

Good luck... would be very interested in your findings. ;)
 
tkeracer619 - Insurance is not really an issue here...I would love to find a company ready to cover me for this but it probably doesn't exist...homeowner insurance in China is actually not very common and most companies don't offer it.
The attitude towards insurance is very different from in the States. For instance if you walked in the street in the US and broke your leg because of an open manhole you could sue the state or the city and get a nice settlement...if the same happened to you in China, everybody would laugh at you because you should just be looking where you are putting you feet...as I said different conceptions...
That's another reason I'd like to be reasonnably sure about this before I take the risk : if I make a mistake the responsibility and consequences will be all mine...
What you say about your wooden floor interests me...I will have wooden flooring in the room where the tank will hopefully be, and I was wondering if the stand should be directly on the concrete slab, or on the wooden flooring (which is tongue & grooved) which might help spread it over a much larger surface ? I suspect the wooden beams over which the flooring is nailed would compact more under the tank, and in the end would create a base which will not be level anymore with all the problems that will inccur...Let me know your thoughts please ! :)

chrispc66 - Unfortunately I think your first hypothesis is the right one...I saw (from far away) many concrete slabs being poured and I never saw anything which made me think that the steel bars inside were being pulled on while the concrete was being poured...

By the way, does my non-load-bearing brick wall analogy have any merit ? Of course I can't imagine anybody doing a large 2 or 3 m2 column of solid brick just for the fun of wasting space, but can I take into account that those non-load bearing wall, which might not have any support underneath (or might), weight over 3T/m2 ?

You mention checking on my neighbours home if they have any heavy piece of furniture... would it be a good thing if they had lots of heavy funiture in their appartement at the spot where I intend to put my tank because it would mean that the slab can stand it, or conversely would it mean that I should not put any more weight on this spot because the building's structure is already too much stressed there and I might recreate another pink shopping mall incident ?

Thanks in advance !! :rollface:
Sylvain
 
My house is custom build by its previous owner and they really overdid the flooring. I don't want it to sag overtime or even think about messing something up so I'm going to line up the main supports on the stand with beams I installed that continue from the bottom of the floor to the earth in the crawl space. Sort of like a stand for a floor, for a stand.

I find it hard to believe a 10 story conrete building cant hold a 360 gallon fish tank. How many of your neighbors have water beds? I just don't think its that big of a deal, @ 130-140lbs per square foot imagine your floor holding 24 people. IF you threw a party, and you all jammed into the corner of the room and danced.... would the building collapse?

Have you tried calling the company who made the building? I know you said the govt office doesnt have plans, maybe someone who built it could have some insight.

Edit: Good point on the insurance, sucks they don't offer it. In the usa we couldn't sue because they would have warning tape and cones up so you don't fall through an open man hole :lol:, because someone sued them 10 years ago..... you can only get away with it once ;) ....

I really think you need to find a chineese engineer, last I checked you guys were pumping out engys faster than any other country.

Also, if that 600Kg/M2 is accurate, your tank will only weigh 530Kg/M2 on a 24" tall tank.
 
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