Sleeved anchor bolts - to grout or not to grout? 6

[atrizzy]

What's YOUR opinion on grouting of sleeved, preloaded anchors (for dynamically loaded equipment)?

On one hand, if grouting after torqueing down the bolts, you don't need to rely on the preload friction for shear resistance.

On the other hand, if a bond occurs between the grout and the bolt, you lose your stretch length. Not to mention that the contractor may well be tempted to grout prior to torqueing.

I've seen it done both ways. What say you all?

 

[dik]

I generally don't, but have seen it done both ways.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik

 

[JedClampett]

We have an option in our specifications and I flip a coin.
Truth be told, we so seldom get the sleeved anchor detail ("we forgot; can we use epoxy anchors?" "too hard to set accurately" "never did it that way"), that it's not worth refining the detail. You have to have a contractor who has their act together when they're pouring concrete to obtain the equipment dimensions and anchors. It shouldn't be hard, but it is.

 

[HTURKAK]

My responds will be;

1- torquing SHALL BE applied after grout gained enough strength,
2- Filling of the sleeve with grout is not a good idea if anchor rod is not wrapped with duck tape or similar.

You did not mention the size and type of equipment. I will suggest to look ;
i -API RECOMMENDED PRACTICE 686 (Recommended Practices for Machinery Installation and Installation Design ),
ii- Process Industry Practices PIP STE05121 Anchor Bolt Design Guide.


The following snap ( copy from PIP STE05121 ) shows the concept.

 

[atrizzy]

HTURKAK, your reference is awesome.

Just one question regarding the detail shown. What exactly constitutes a "elastometric, moldable, non-hardening material"? Is this essentially a rubber fitting?
I'd almost be more inclined to instruct the contractor to wrap the entire rod in tape...

 

[dik]

Nut 2 and nut 3 should be different heights...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik

 

[hokie66]

Sleeves are used on anchor bolts for a variety of reasons. Some are just for adjustment, and should be filled after erection for corrosion prevention.

Then, there are those which are petensioned, and they also should be filled, after tensioning.

Whether the filler material is grout, grease, or something else depends on its purpose.

 

[HTURKAK]

Elastometric, moldable, non-hardening material ,shall be soft moldable material . Such as foam pipe insulation .

The use of sleeve, when small movement of the bolt is desired after the bolt is set in concrete. IMO, it should not be too hard to set the anchors with sufficient accuracy and eliminate the need for sleeve.

In past, i preferred to wrap the entire rod with duck tape and preferred the use of template for large diameter anchors ( sometimes the dia could be 4 in . or more..)

 

[dauwerda]

I have often seen sand used as the "elastomeric, moldable, non-hardening material".

 

[HTURKAK]

This is copy and paste from API RECOMMENDED PRACTICE 686 ;

( 3.12.3 Prior to pouring grout, the area between the top of the anchor bolt sleeves and the bottom of the mounting plates
shall be packed with a soft moldable material (such as foam pipe insulation))

I suggested PU foam . However , IMO , the use of sand is O.K. A pink star for this respond (simple but working alternative )to Mr. dauwerda .

 

[r13]

We only plug the top of sleeve to stop grout.

 

[dik]

I've even seen crumpled up drawings used for a grout stop...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik

 

[TLHS]

I've used Sikaflex-2C SL to fill sleeves like that and have had no complaints from the contractors.

On the other hand, I've also had people just fill them with spray foam. Not a huge fan of that because it's not actually flexible, but the things haven't stopped working.