Question for the engineers

[phinsperger]

If a horizontal 13 guage pipe of 2 3/8" diameter carries a given evenly distributed load over a given span, what diameter would 2 smaller dia pipes of the same guage have to be to carry the same load over the same span?

This illustration may help to clarify;

[Marcel R. Cyr]

Originally Posted by phinsperger

If a horizontal 13 guage pipe of 2 3/8" diameter carries a given evenly distributed load over a given span, what diameter would 2 smaller dia pipes of the same guage have to be to carry the same load over the same span?

Originally Posted by phinsperger

This illustration may help to clarify;

Attachment 5493

Hi. Paul;

I am no Engineer, but would 1 1/4" twice come close to the right answer?
Just curious. ha. ha.

Marcel

[Brian E. Kelly]

Pipes are not generally load bearing members.

[Michael Larson]

Originally Posted by mcyr

Hi. Paul;

I am no Engineer, but would 1 1/4" twice come close to the right answer?
Just curious. ha. ha.

Marcel

I get 1-3/16 HINT-THINK ABOUT CIRCUMFRENCE

[Marcel R. Cyr]

Originally Posted by bkelly2

Pipes are not generally load bearing members.

Brian; I think we all know that, but can you solve the equation?

Marcel

[Marcel R. Cyr]

Originally Posted by mlarson

I get 1-3/16 HINT-THINK ABOUT CIRCUMFRENCE

Hi. Mike;

I guess we are on the same page on this one.

I tried 1 3/16", but found I was under by .028 of an inch and over by .009214 by using 1 1/4".
I gather we are both talking about Dross Sectional areas?

Marcel

[dchew]

It depends on if you want the same deflection or the same maximum stress level in each pipe.

In a nutshell, you need to look at the moment of inertia property of each tube. For the double tube configuration, you need to assume that each tube is carrying 1/2 the total load. There are several other assumptions that will be needed to make (same materials, depth/span ratio, etc.), but the most important one for this case is that the material is the same.

The stress AND the deflection are both inversely proportional to the moment of inertia. So, if you know the moment of inertia for the single tube setup and want the same stress level and deflection for the double tube setup, you want the moment of inertia for each of the smaller tubes to be 1/2 that of the big one.

Q.E.D. ("quod erat demonstrandum")

[Michael Larson]

Yes but that's way too much work.
Think about how an arch works in transfering the load at the top of the arch to the vertical "column"

[Marcel R. Cyr]

So, what is your conclusion analysis??

[Jay Moge]

Wasn't there something on the BB last year about how (i'm talking flow and volume now) two 1/2" pipe doesn't equal the same as one 1" pipe? does the same apply here? Not to mention that the thickness of the material is the same in both sizes so the smaller pipe should hold more weight if you think of it on a 1.1 scale.

[Michael Larson]

Originally Posted by mcyr

So, what is your conclusion analysis??

Perhaps will Paul return and tell us.

[Brian E. Kelly]

Originally Posted by mcyr

Brian; I think we all know that, but can you solve the equation?

Marcel

I does not look lioke an equation to me Marcel, it looks like using something made to do one job, and then asking it to do another job.

Not enough info. Is it seamless material? Is the piping metal, plastic? is the piping supported by hangers?

What weighs more 1 lbs of lead pipe or 1 lbs of Aluminum pipe?

Tell me who made the pipe and I will google the answer.

[Michael Larson]

Originally Posted by bkelly2

....
Not enough info. Is it seamless material? Is the piping metal, plastic? is the piping supported by hangers?

What weighs more 1 lbs of lead pipe or 1 lbs of Aluminum pipe?

Tell me who made the pipe and I will google the answer.

Your thinkg too hard Brian. Maybe it will be clear in the morning when the head clears up.

[Brian E. Kelly]

Originally Posted by mlarson

Your thinkg too hard Brian. Maybe it will be clear in the morning when the head clears up.

Perhaps, perhaps not.
It seems I can still manipulate the spell check feature.
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[Michael Larson]

Originally Posted by bkelly2

Perhaps, perhaps not.
It seems I can still manipulate the spell check feature.
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Yep, forgot to spellcheck that one. (Good catch) Better put my glasses on or buy a bigger monitor