pipe support 2

[Ciaci]

Hi everyone,
Some clients asked me to change the pipe support. Initially it was a concrete plinth with a plate on the top anchored with expansion bolts. They asked me to change the support using a plate with no expansion bolt simply inserted in the concrete plint. Since I am still new in this work, i accepted it. But this, in my opinion, does not really agree what I studied at university. First of all in my opinion, to insert the plate into the concrete could give problem due to the different thermical expansion between steel and concrete. Therefore it seems to me bizarre that there is not system to anchor concrete to steel.
In the attachment is possible to see what I did at the beginning (right) and what they ask me to do (left).
Maybe there is an explanation to this. I want just to understand it in order to avoid mistake in the future.

 

[LittleInch]

I've seen both, but I must say I've never seen a plate with triangular wedges in before - where did they come from??

The issue isn't so much one of expansion - the actual amount of differential movement is minute for something as small as this.

The issue is about the forces the plate will see in operation. with those weird wedges, this appears to be designed to limit, a little bit, the sideways movement of the pipe. given that any serious force will simply result in the pipe lifting up and then falling off the support this anticipated sideways force must be quite low, however it means that force needs to be resisted and without some means of holding the plate to the plinth, the whole plate could move sideways.

I have seen plates with bolts and rods / short sections of re bar welded to the bottom to be set into the plinth just after pouring to give the plate some grip, but it comes back to anticipated forces on the plate from the pipe moving. sort that out first then apply some logic to the fixing of the plate.

Those angle welded on longitudinally are very odd....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Ciaci]

I decided to weld in this way, because I have followed a specific that give us the client... Which do you think is the better way to weld them?
Littleinch, in our experience wich is the best solution to connect the plate with the plinth for this kind of support?

 

[LittleInch]

What is the purpose of the angles?

I still don't know what forces the plate is seeing other than vertical load.

If you want to restrict movement sideways normally a shorter length is used and they are welded like an L shape with the side part taller than half of the diameter.

It must be said that resting pipes direct onto plates / bars is now not seen as a good thing due to corrosion potential under the pipe and hence the use of clamp and shoes is much more common.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

Take the plate with the angles and turn it upside down; the angles will embed in the concrete and secure the plate.

It is recommended to install a rod on the sleeper and structural support as per L.C Peng in his book "Pipe Stress Engineering". In many cases, when pipe sits on a flat metal support, moisture is trapped which leads to corrosion. The round edge of a pipe resting on the round bar prevents moisture from accumulating.

http://stoprust.com/i-rod-pipe-supports/

 

[dbill74]

Nothing wrong with using expansion bolts to secure a steel plate to the concrete. It is done all the time in building construction to secure steel columns to concrete foundations. It is not uncommon to use these same expansion bolts to attach suspended pipe hangers from concrete slabs.

 

[MJCronin]

You have too much concrete and you have made the support too "long" for the pipe (axially). There is a large probability that the support will skew on the plate.

If the piping is insulated, you will need some type of clamped or welded on "shoe"

The typical piping loads are not that high and your lengthy support could cause problems if the piping moves in the least due to thermal expansion.

This type of support has been done a bajillion times before...

Look at these websites and tell us what you think....

http://www.pipepier.com/pipe_pier_150.php

http://www.pipingtech.com/index.htm?utm_source=Main-Nav

http://www.anvilintl.com/products/pipe-hangers-and-hardware/pipe-guide-and-slides

MJCronin
Sr. Process Engineer

 

[Ciaci]

MJCroning, I completely agree with you in everything, thanks for the references.( I found out that my specs are from 1991, but unfortunately the choice is about the clients)
dbill74 The problem is that they told me to do not use the expansion bolt, but to insert directly the plate in the concrete.

 

[europipe]

Like mr. Cronin said.
This is much overdone for a small pipe like this.
Too much money there?
You can always weld a few nails under the plate for securing in the concrete.