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Post by fishfever on Dec 30, 2009 17:57:42 GMT -5
I have been mulling the purchase of a larger tank (at least 55g, up to 125g), especially with all the great deals on CL lately. (I really shouldn't be looking, but I can't help myself it seems.) Anyway I recently missed a 55g with all equipment and custom real wood stand big enough for probably 100g for $75. Now there's another one like it although it doesn't seem to have filters and a heater. I'm also looking at a beautiful 125g cherry with cherry wood stand which would match our furniture and floor real well (more money of course).
At up to 55g, I don't think I would worry about the floor supporting the load. But at 125g, we are talking about well over 1,000 lbs of water plus the tank/cabinet. I could put it in the basement but then it would be defeating the purpose of having the aquarium in the first place. There is a place in the great room where we have our small 26g in which there is a huge solid wood beam below that crosses the entire floor (I saw it during construction and know exactly where it is). I could put the tank cabinet perpendicular to this beam, centered over the beam against a dividing wall. I think it helps some that the 125g is long and spread out more versus a tall, high tank (this is another reason I am interested, it is easier to maintain a shallower tank). But I'm still concerned that this could still be too much weight for a non-basement floor. Although I'm still just thinking about it, anyone with a large tank (or have had a large tank) not on the bottom floor have thoughts about this?
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Post by murdock6701 on Dec 30, 2009 22:05:45 GMT -5
lots of good questions! what is the size and spacing of your existing floor joists? for example, 2x10' at 16" on center spanning 12' w/ diagonal wood cross bracing between the joists - the average home is designed for 100 lbs per sq ft - depening on the size of the tank length, you can use these numbers to calculate the weight dispersion - don't forget to add in the weight of the tank alone empty, and then filled w/ gravel and water.......the beam is designed to hold the weight of the floor joists ans generally not engineered for additional weight - it may be necessary to shore up the floor w/ a small 2x4 wall onder the existing joists ( a stud under every joist) - hope that helps!
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Post by fishfever on Dec 31, 2009 12:58:36 GMT -5
Murdock, the floor joists are an engineered wood product (TJI230). They are on roughly 12" center to center spacing with 14" depth. Here is a image with the design info from the manufacturer's web site: i558.photobucket.com/albums/ss25/fishfever/TJIJoistDesign.jpgOne of these on end doesn't look like much with the 3/8" webbing but due to the high compressive strength of the wood and "I-beam" design they are quite strong for vertical loads. They were used throughout our house in we never hear any creaking floors. Here is a picture of the two joists in play (the ones that would be under the tank) in an unfinished area of the basement (the area directly under the tank is finished so you can't see them there): i558.photobucket.com/albums/ss25/fishfever/TJI230Joists.jpgI did a quick calc for floor deflection (note: I'm not a structural engineer) making the assumption that the 125g tank (18" width) would rest on two of these lengthwise. Probably not a perfectly distributed load, but assuming a 6 ft long tank then it is spread out over 12 ft of joists. Further assuming a filled tank weight plus cabinet of roughly 1500 lbs that is about 125 lbs/linear ft which is the "w" in the equation for floor deflection. L is 6 ft, d is 14 in (depth of joist) and El is 509x10^6 in-lbs for 14" deep TJI230's. Plugging in the numbers I get just under 1/64" deflection due to a fully loaded tank plus cabinet. There should not be any other static load in this area other than the small weight of the joists, sub-flooring and flooring. The joists rest on a large wood beam that is centered on the room perpendicular to the joists. The builder actually replaced the original beam with a larger one after doing some calcs. Here are two pics of it: i558.photobucket.com/albums/ss25/fishfever/Supportbeaminbasement2.jpgi558.photobucket.com/albums/ss25/fishfever/Supportbeaminbasement.jpgThe dimension extending below the ceiling is 14" so it's probably about 16" total. The width is 4.5" but without the drywall it's probably 3.5" (solid one-piece beam). The idea would be to center the tank perpendicularly over this beam (on which the joists are resting) against the dividing wall (not an exterior wall). Assuming the support of this beam behind the wall is very strong and rigid (I believe a bunch of networked/paralleled 2x4's in compression), it doesn't seem like I would have trouble with this part. I guess it may come down to how much additional loading other than the tank already exists to be translated through the same beam structure (this would not include the joists, they only need to support the tank weight).
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Post by fishfever on Dec 31, 2009 13:44:52 GMT -5
Thought about this some more, and I believe the floor deflection is actually al ot lower if we assume the tank is centered over the beam (and it should not deflect there). Then we are only dealing with max deflection at +/-3 ft from the center, and if I use L=3 ft in the deflection equation then the calculated deflection is about 0.0026" or less than 1/256th of an inch which seems negligible.
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Post by murdock6701 on Dec 31, 2009 18:46:08 GMT -5
LMAO! you did your homework well - didn't even have to look at any of the pics you attached - I am not a licensed structural engineer, but I am an architectural engineer w/ a lot of extra classes I took on my own in structural engineering and from the size of the beam and the TJIs, you should be OK - I just build everything and design everything to "hurricane 5" - btw, if you weigh over 300 lbs., you may NOT feed your fish!
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Post by bikeguy33 on Jan 1, 2010 0:28:14 GMT -5
in my experience in maintenance... i have never seen additional supports used for heavy tanks. as long as your house is to at least spec, the floor is designed to hold that much or more according to a buddy who is a journeyman framer. i have seen many many huge tanks on main floors.
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Post by fishfever on Jan 2, 2010 10:23:43 GMT -5
Well I feel better about this after listening to your inputs and especially looking at my situation in more detail (and even running some of those calcs). Now I just have to think about other considerations, like do I really want to change that much water (the bucket thing is not going to be that practical any longer). Even if I don't pull the trigger now at least I've done my homework on the weight issue...
BTW murdock, I'm only 6' and 185 lbs (I'm assuming I gained 5 during the holidays) so we should be okay at feeding time! ;-)
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