ACI-318

[rulljs]

I'm looking through ACI-318 trying to find out where (if anywhere) it calls out for a minimum required thickness of grout on top of a pedestal, in this case I have an octagon footing supporting a piece of equipment. I'm used to seeing 1" to 1 1/2" grout thickness on regular footings but can't seem to find where this thickness comes from.

Any input on this would be appreciated...

 

[civilperson]

Grout is a means for constructibility of large base plates bearing on concrete that may not be flat and level. The requirement for a specific thickness is a function of flow dimension, (from either one-sided or multiple grout entrances). Check with the grout manufacturer for recommendations of minimum thickness and need for relief holes in the base plate.

 

[blake989]

You may want to check out Committee 351 - Grouting for Support of Equipment and Machinery. The answer depends on size of pad to be grouted, type of grout to be used, and tolerance required.

 

[rulljs]

Thanks for the quick responses guys, much appreciated!!

 

[AggieYank]

I haven't looked in ACI, so I may be off on this. I believe a minimum grout depth is for constructability. For example, no one would be able to fill a 3/8" deep void under a 16" x 16" elevated base plate with grout. It would be too hard to fill the void. That's why we use 1 1/2" or 1". I've seen contractors use 3/4", but when I'm specifying, I usually just show 1 1/2".

 

[UcfSE]

It also has to be thick enough to contain the leveling nuts and have room for tools with some tolerance.

 

[miecz]

According to the Five Star Product Information Catalog, "for placement thicknesses of less than one inch or greater than three inches, call the Products Emgineering and Technical Information Center.