Pipe Support - Anchoring Question

[securityisa]

Hi,
Please redirect this thread if it is not in the correct category.

Is there a general rule of thumb for the length of the anchor that must be in the concrete for pipe supports?

Is it common practice to grout a piping support?

Thank you

 

[TLHS]

You're going to have to give more information. There are effectively an infinite number of possible pipe support arrangements, load effects, load combinations, structural systems and anchorage methods.

What you use for a 15 foot tall vertical only pipe support holding a 10 inch pipe is going to be significantly different than what you use for a 2 inch pipe directional stop cantilevered off a building column or a 42 inch overland pipe.

 

[securityisa]

It is an 18 inch pipe, never higher than 4 feet from the ground. Supports are anchored in concrete. Type of support is horizontal standard beam welded on two verticals. I understand that the anchors minimum diameter and minimum length drilled in concrete can be calculated with loads, but pipefitters in the industry rarely use engineering plans to make the supports. I hope without getting in core calculations there is a common practice of the size of bolts and length drilled in concrete.

Also for my second question if grouting base of support is common practice ... does it depend on loads?

Thanks,

 

[SlideRuleEra]

I hope without getting in core calculations there is a common practice of the size of bolts and length drilled in concrete.

Sorry, the answer in no. As TLHS stated, there are too many variables.

You did not ask about the number of anchor bolts for each independent support. IMHO, one anchor bolt is almost never a good idea. Use at least two; for a vertical support, four anchor bolts are commonly used.

Length of the anchor bolts also depends on the concrete thickness. Anchorage to a 6 inch thick concrete slab would be treated differently than anchorage to a 6 ft. thick concrete mat.

Spacing of anchor bolts, because of concrete properties, is another consideration.

Your question about grouting the base of a support is a little easier to answer. Again, IMHO, grouting is a good idea. The grout helps protects the anchor bolt / concrete interface area from corrosion. A good idea in an industrial application, which is what I assume you are working with. For light to moderate loads grout has nothing to do with load carrying capability. For heavy loads, grout is essential... and must be correctly installed to perform adequately.

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[bridgebuster]

1. What sort of lateral forces do you have in the pipe? What pressure and temperature does it operate at? If these aren't a concern use 4-3/4" diameter Hilti Kwik bolts to the maximum embedment.

2. If you're setting the base plate on leveling nuts, the compressive strength of the grout doesn't matter. If not, then it does.

 

[dhengr]

Securityisa:
I’m not aware of any rules-of-thumb for something like this, as mentioned above. There are just too many things to consider, in a proper pipe support design. It sounds like there is a serious need for some experience on this subject in your office. There is judgement, knowledge and an understanding of the potential problems which comes with doing hundreds of these designs which finally allows an experienced designer to make some determinations without a complete detailed design of every support detail. Rules-of-thumb in the hands of pipefitters can be dangerous, real design experience and good sound judgement is good.

 

[ingdaniel]

well,

I dont know if you have any information of horizontal loads... But you cant do this.

- Use 4 3/4" bolts (minimum size of bolt for industrial use)
- If is preinstalled 12d length in concrete... if post-installed use hilti manual.
- Grout is for leveling.... you probably can level the support without grout because are small supports (4 feet)

 

[TLHS]

Pipefitters in all the industries I've been involved in would very much follow engineered plans when supporting an 18" pipe.

It's not usually a difficult engineering problem (there are exceptions when you have excessive anchorage loads or weird seismic arrangements of the system) but it's something that needs to be looked at properly.