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Old 06-16-2012, 03:15 PM   #31
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Dead Loads / Struct. Eng


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Originally Posted by goosebarry View Post
If your deadload is 37 psf, then your estimating the weight of the shower to be about 3000 lbs. Is that right?
1300 tile and materials, 500 sheetrock, 550 fibercement, 500 tub, 200 toilet, vanity, misc materials.

plus another 1350 for the water when its filled!!!

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Old 06-16-2012, 03:34 PM   #32
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Dead Loads / Struct. Eng


Seriously though, if I'm going to spend the damn money on an engineer, whhy not just over-engineer the damn thing and spend a couple hundred bucks on some steel I-beams and run those down the top of it, and make the load bearing tie-ins out of 2x6s instead of 2x4s. Problem solved, no?

I guess, in all seriousness, what I"m really looking for, is peace of mind.

As I say, the inspector sez its fine, but he has no god*%(*$()*()F#*#&* liability, you know?

Thus the desire for peace of mind.
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Old 06-16-2012, 04:55 PM   #33
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I am a structural engineer by trade, but it appears the OPS has little regard for the engineers he has dealt with. So be it. I will take a crack at explaining the process of determining live and dead load, since there has so far been little discussion of this question, which was after all the original OPS point, on this thread.

First off, you need to get the definitions correct. Dead load is the vertical load on the floor due to permanently fixed objects and material, which typically includes framing, drywall, permanently fixtures such as a tub, tile, cement board, and fixed in place plumbing fixtures. Live load includes any transient load expected to vary over time, such as wind load, seismic loading, people, and water added to the tub (unless you plan to keep the tub permanently full).

In either case, to compute the effective distributed load on an area, you add up the total load (dead or live), and divide by the area. So for example, if you have an 8x10 foot bathroom, that is 80 square feet, and if the total dead load is 5000 lbs, the effective distributed load is 62.5 psf.

Live load is more complicated, and is often code driven. You CANNOT simply add live loads together, since they do not always act in the same direction (seismic load is horizontal and vertical), wind load can be up or down or sideways. In most residential applications, live load is taken from code, and computations are typically developed only for the vertical live load case.

In some cases, you CANNOT use distributed live load. Such a case would be a heavy bathtub supported on four small supports, for example a claw foot tub. Then the dead load of the tub, and the live load from the water and the person sitting in the tub, would need to be analyzed as point loads on the joists. Point loads often generate higher stresses than distributed loads, and must be properly analyzed.

Bathroom loading analysis is somewhat more difficult than other rooms, since the point loads can be substantial, and they are often combined with distributed loads. This is of course a DIY forum, not a forum on structural mechanics. Typical framing practice is adequate for most bathroom installations, but may NOT be adequate in cases where you are installing heavy point loads, such as your case. In that case, you may wish to seek out professional advice, or you may elect to take your chances on conventional framing. Getting structural design off an internet chat forum is another option, although the consequences of failure can be most unfortunate, and no one on a chat forum is going to assume responsibility for the tub going through the floor.
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Old 06-16-2012, 05:36 PM   #34
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Originally Posted by Daniel Holzman View Post
I am a structural engineer by trade, but it appears the OPS has little regard for the engineers he has dealt with. So be it. I will take a crack at explaining the process of determining live and dead load, since there has so far been little discussion of this question, which was after all the original OPS point, on this thread.

First off, you need to get the definitions correct. Dead load is the vertical load on the floor due to permanently fixed objects and material, which typically includes framing, drywall, permanently fixtures such as a tub, tile, cement board, and fixed in place plumbing fixtures. Live load includes any transient load expected to vary over time, such as wind load, seismic loading, people, and water added to the tub (unless you plan to keep the tub permanently full).

In either case, to compute the effective distributed load on an area, you add up the total load (dead or live), and divide by the area. So for example, if you have an 8x10 foot bathroom, that is 80 square feet, and if the total dead load is 5000 lbs, the effective distributed load is 62.5 psf.

Live load is more complicated, and is often code driven. You CANNOT simply add live loads together, since they do not always act in the same direction (seismic load is horizontal and vertical), wind load can be up or down or sideways. In most residential applications, live load is taken from code, and computations are typically developed only for the vertical live load case.

In some cases, you CANNOT use distributed live load. Such a case would be a heavy bathtub supported on four small supports, for example a claw foot tub. Then the dead load of the tub, and the live load from the water and the person sitting in the tub, would need to be analyzed as point loads on the joists. Point loads often generate higher stresses than distributed loads, and must be properly analyzed.

Bathroom loading analysis is somewhat more difficult than other rooms, since the point loads can be substantial, and they are often combined with distributed loads. This is of course a DIY forum, not a forum on structural mechanics. Typical framing practice is adequate for most bathroom installations, but may NOT be adequate in cases where you are installing heavy point loads, such as your case. In that case, you may wish to seek out professional advice, or you may elect to take your chances on conventional framing. Getting structural design off an internet chat forum is another option, although the consequences of failure can be most unfortunate, and no one on a chat forum is going to assume responsibility for the tub going through the floor.
tldr; I have to go to work. THANK YOU IN ADVANCE for specifically address the OP.

Look forward to reading!

just fyi any readers, I've decided to spend 200 extra dollars over-engineering the whole thing, making the bearing walls 2x6s and basically putting another 6 or 7 2x8s into the system to make the whole thing invincible. No money spent that doesn't become value for the home.
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Old 06-16-2012, 08:39 PM   #35
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Originally Posted by Ghengisconrad View Post
I HATE paying people for things I don't understand myself, because they usually do what I come around to realize is a poor job after my understanding/ability catches up with what they have done, and money is already EXTREMLY tight.

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