# Fill tall pole with concrete - cure?

Nehmo Sergheyev wrote:

No, they are completely different. Stiffness is related to the slope of the stress/strain relationship (elastic modulus) in its linear range. Strength is how high the curve goes before failure. Not the same at all. A material can be very stiff (glass), yet not strong (glass with a small surface crack). A material can be very strong (spring steel), yet not very stiff (spring steel).

>

Let's say you support the empty pipe as you say above (as a simply supported beam) and measure its deflection in the center. Now stand the pipe up, fill it with concrete and let it cure and then support it the same way again and measure the deflection in the center. Which case do you think will have greater deflection? And now explain why your stiffer pipe has more deflection than the less stiff pipe that has no concrete.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

I'll go along with that experiment. But you can't make the conclusions, let alone explain them, before you conduct the experiment.
The pipe is a beam, 8 feet from support to support. The exterior diameter is 3 inches. The wall thickness is the same in both. We'll use schedule 40 because that's the example I think I can get.
One pipe is empty and is referred to as "empty"; the other pipe is filled with cured concrete and is called "filled".
The deflection in either case is hard to measure when we are only using the weight of the pipe itself to cause the deflection. However, I can stand on the center of the pipe. I weigh 211 pounds. (If the experiment is conducted without me, someone else can substitute.)
In the filled pipe, there will be small deflection. It would even be hard to measure with regular rulers.
In the empty pipe, there will be considerable, easily noticeable and measurable deflection.
There will be more deflection in the empty pipe than in the filled pipe.
You disagree with my last 3 paragraphs. Correct? Now, all we have to do is find an acceptable way to do this experiment. We need someone impartial to judge, and perhaps you want to put some money on this?
Well, I don't want to be rude. If you don't want to bet, that's okay. But the loser should have to do something.
-- (||) Nehmo (||)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Nehmo Sergheyev wrote:

The scenario is the self-weight only, no applied load.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Why would you be afraid of a little weight? Weight is the force that is going to make the pipe deflect. Besides, as I said, the deflection of filled pipe is going to be hard to measure if we only use the weight of the beam. We have to measure relative stiffness, you know.
-- (||) Nehmo (||)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
replying to Matt Whiting, Kevin Hobart wrote: Air can be depressed. cement can't. I'm sure we can agree air in metal makes metal weaker. A pipe filled with cement would be almost impossible to bend. Vs. the same pipe with only air inside it. So, in answer to the question, I would say that I would go one step further and fill a few sticks of conduit with cement and add them to the pipe, then fill the pipe with cement. Just depends how stiff you want to make it. The "Anchor Cement" sets up in about 10 minutes. I want to believe it cures at just over 7,000 psi in just a day or so. If you wanted to add a little conduit to it , I bet you could double the strength as well. I hope this helped.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Ahhh, that explains a lot. Book learnt but no experience. For your information, a hole in the ground is where you can pour a foundation, your butt is just above your legs. You will have to know the difference when you get out into the real world.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

That was rude, and unnecessary.<PLONK>
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

It's not something I would have wrote, but it's not that horrible. If that's the level you plonk at, you're going to be doing a lot of plonking. Glenn didn't name call, threaten, or even swear. Indeed, he was trying to avoid directly saying Matt doesn't know his ass from a hole in the ground.
And if you'll notice, Matt, in different ways, is rude a lot himself. For example, he's paraphrasing me incorrectly in this very thread. He's pretending there's some third party reading his post by itself. I suppose If they were to do that, they might be inclined to side with him. It's vary irritating, and he knows it. When you respond to Matt, the first thing you have to do, time and time again, is attempt to correct what he claims you said.
Now, that's enough of that. The issue is simply whether a concrete- filled steel pipe is stiffer than one that is empty. I say it is. Matt and Bob, amazingly, disagree with me.
Glenn was trying to explain how Matt could possibly be thinking this way. I've been wondering myself. Anybody who's had any real-world experience with a concrete-filled tube knows it's stiff. Thus, Matt must not have any experience of this nature.
-- (||) Nehmo (||)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
wrote:

I can and I do, as you say. Newsgroups are like the first hockey tryout with 50 skaters on the ice. You don't (can't) pick out the good ones, it takes too much time. The cuts are quicker and easier to see and make. When the crowd is gone you can focus on qualities of individuals.
--

MichaelB
www.michaelbulatovich.ca
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Nehmo Sergheyev wrote:

Show one place where I paraphrased you incorrectly. Just one example.

Let me see ... Bob is a PE and SE with many years of experience. I'm a PE and nearly complete with a graduate degree in SE (need to complete the final capstone project). And your credentials are???

Amazing that you can make this claim when you don't even know the difference between strength and stiffness.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Michael Bulatovich wrote:

Michael, don't sweat it. People of his IQ say dumb things all the time.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Plonking requires no sweat, and this is not a question about IQ. It's about EQ.
--

MichaelB
www.michaelbulatovich.ca
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Michael Bulatovich wrote:

:-), yes, very true!
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Glenn wrote:

From the mouths of babes...
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

The phrase, "pearls of wisdom can come from the mouths of babes, fools, and drunks", which is often used elliptically as you did, means that something said my someone uncorrupted or uninhibited is true. Thus, in the context you used it, you are saying what Glenn said is true. In other words, you are agreeing you don't know your ass from a hole in the ground. -- (||) Nehmo (||)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
wrote:

sized pole (usually 4") so you are not going ot get something bigger in there without a lot of work.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

Several years ago I filled a basketball pole with concrete. I put a 5/8" rebar down the center and then poured in the concrete. It was an improvement but it didn't make it as strong as I had imagined that it would. Concrete cures by chemical reaction so it doesn't matter if the mix is inside a pipe or under water - it will still cure.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Mike Hammer wrote:

The rebar on the pipe centerline was just wasted metal.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Snip:
The concrete fill of a thin wall tube, i.e.: a pipe pile or lally column increases resistance to buckling in compression and bending failure in the case of piles exposed to lateral loads, other than that, it just adds mass.
Tom

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Tom Cular wrote:

And it really only helps in bending failure when buckling is the failure mode.
Matt
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>

## Site Timeline

• Share To

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.