U-Bolt Installation

[DGrayPPD]

Hello all,

Can someone give me a breakdown on the correct method for installing u-bolts? And what I mean by this is, my company has a standard detail for u-bolts that shows them being used as an anchor or a guide. Is it common for a u-bolt to be used as an anchor? I have only seen them used as a guide personally, so I am curious if using them as an anchor is a thing or if it is another practice that should be avoided.

And a follow up to that question. Say I have a pipe running underneath a beam with not enough clearance to use a hanger support. What are the cons of using a u-bolt on the underside of the beam rather than the top side?

Thanks,
DGrayPPD

 

[LittleInch]

Did you not read the post below yours? "torque for U bolts"?

A U bolt is not supposed to be an anchor which can take any significant load / force.

For me it's something to be avoided.

Underneath it is tat the end connection become loaded with the vertical load / weight - above the beam it doesn't.

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

 

[DGrayPPD]

Actually, I posted my question and once it posted I noticed the post below it for the "u-bolt torque" haha.

I figured that answered one question but I was still curious about using them on the underside of the beam. Your point about the end connection becoming loaded with the vertical load/weight is what I was thinking about that had me concerned.

So besides the use of rod hangers, any recommendations on what to use on the underside of a beam?

 

[JGard1985]

Hi

I've never seen a u-bolt used as an anchor to withstand axial pipe load. Seems like you would put the u-bolt into bending, if it worked.... Anyway, looked at Anvil, 137SS U-bolts, gives ratings for normal (vertical) and side loading. No axial load. I don't use u-bolts for axial restraint in my designs and haven't seen them used for this purpose in Nuclear Power piping applications.

With regard to your question, and limited detail, I don't see any problems to using a u-bolt with some sort of steel to connect to the framing. I use angle iron. If using as a guide, I like to specify a minimum gap to allow free axial expansion. You don't need the field adding additional restraints where you haven't modeled them. I once had the field clamp the u-bolt so tight that we ended up coldspringing the pipe and rupturing during a transient.

Jeff



Jeff
Pipe Stress Analysis Engineer

http://www.xceed-eng.com

 

[DGrayPPD]

Thanks Jeff,

The more research I'm doing, the more I'm seeing that u-bolts aren't necessarily the best type of pipe support unless it is used in small bore piping.

 

[JGard1985]

No problem. Depending on how tight you need to be to the underside of the beam and how big your piping is, a welded frame support may be your best bet

Jeff
Pipe Stress Analysis Engineer

http://www.xceed-eng.com

 

[DSB123]

For small bore piping they are fine. Any size 3" and above forget the use of U bolts. There are Grip Type and Non Grip type. Used extensively for pipes 1.5" and below.

 

[DGrayPPD]

Thanks guys,

Seems to be another one of those areas where someone in the past decided to use them and everyone else went along with it. Since I started I have seen u-bolts used on every project for sizes up to 18" NPS. Glad I finally decided to ask the question.

 

[DGrayPPD]

Has anyone had issues similar to what is shown in the picture? (Notice the I-Beam)

Client specifications called for I-Rod style u-bolts.

 

[europipe]

Nice painted

 

[DGrayPPD]

Was the I-beam just undersized and that's what is causing the bend?