1 - 7 of 7 Posts

Joined

·
455 Posts

in theory however a Wx14 beam should be fine as the fishtank is a distributed load over your floor supports which are (in theory) spaced at 16" O.C. max. if your tank is 48" wide it spans 4 beams and your 800 lb load is divided by 4 and then is factored by the distribution. i am however not an engineer and its been 5 or more years since i took structures.

http://www.google.com/search?hl=en&...sDD&q=wood+beam+load+calculator&aq=f&oq=&aqi=

http://www.google.com/search?q=beam...s=org.mozilla:en-US:official&client=firefox-a

those links have some beam load calculators. the formulas are correct but i dont remember which ones to use :blush:

Joined

·
643 Posts

A 3x3 atop a 4x4 would at best give you a 3x7 since an inch of the 4x4 is not supporting anything, and depending on how they are attached to each other, I'm not sure that it even has that much lateral strength. An architect/engineer could better answer your question, but I'm sure they would need more info as well.

JMTCW

Joined

·
17,248 Posts

thus spreading the load out

I have a 125 tank & I installed it directly over a beam in the basement

The joint between the 3 x 3 and the 4 x 4 does not lie in the center of the composite beam. All loads placed on this combined member will result in a shear force parallel along this joint. The only thing resisting the shear force is the quantity and thickness of the nail/screws or whatever is holding the composite beam together.

The limiting factor may not be strength of the wood.

Joined

·
17,248 Posts

Except he stated the tank will run parallel to the joist & thus only sit on one joist - maybe 2as the fishtank is a distributed load over your floor supports which are (in theory) spaced at 16" O.C. max. if your tank is 48" wide it spans 4 beams and your 800 lb load is divided by 4 and then is factored by the distribution. i am however not an engineer and its been 5 or more years since i took structures.

Joined

·
5,832 Posts

I also was not clear whether all of the joists were added on to in the same manner, or possibly only the one that is going to support the fish tank. Since the tank is apparently aligned along the axis of one of the joists, it may lie entirely on one joist, in which case it would have to be treated as effectively a point load. If it is a point load, the critical factor is the distance from the support ends, along with the weight. Once we know the method of construction of the beam, and the location of the tank, we can compute the bending stress and estimate the factor of safety against failure.

1 - 7 of 7 Posts

Join the discussion

DIY Home Improvement Forum

A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Come join the discussion about tools, projects, builds, styles, scales, reviews, accessories, classifieds, and more! Helping You to Do It Yourself!

Full Forum Listing
Explore Our Forums

Recommended Communities

Join now to ask and comment!