Omitting Base Plate Grout
Omitting Base Plate Grout
(OP)
I have designed a large retail/warehouse store. Some of the columns support 250k loads. The same contractor is pouring the footings and going to erect the steel. He wants to omit the grout. He states that he is going to pour the footings so smooth that the column baseplate will bear directly on the concrete. THese are 10'-0"x10'-0" footings. I do not beleive he can pour the footing to within 1/16" of the proper level. Also , this Contractor is friends with the Owner, so I am hte outsider.
Can anyone help to support the case of keeping the grout? I have read thru Steel Design Guide, 2nd edition.
Can anyone help to support the case of keeping the grout? I have read thru Steel Design Guide, 2nd edition.






RE: Omitting Base Plate Grout
-Concrete shrinks more than non-shrink grout. No guarantee of proper bearing.
-Not a chance that concrete will flow as well as grout to fill all voids.
Anyone else got any others?
RE: Omitting Base Plate Grout
Anyway, how will they finish the concrete that smoothly around the anchor bolts? I just cannot see how they will be able to ensure full bearing without grout.
RE: Omitting Base Plate Grout
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Omitting Base Plate Grout
If you allow it and it doesn't work, who looks bad?
Mike Halloran
Pembroke Pines, FL, USA
RE: Omitting Base Plate Grout
The contractor apparently believes that he can not only make the bearing surface flat and level, but also to perfect elevation. Doing so is so time consuming and unreliable that no one else does it.
I never would permit it for those kinds of loads.
RE: Omitting Base Plate Grout
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
We let them do it... But, we assumed that the bearing only happened at the leveling nuts and designed for a thicker base plate. In the end it didn't end up being a very big deal. The base plates were not heavily loaded and this only resulted in a minor change to base plate thickness. Maybe we added a stiffener to one of the columns or something.
To me it's a matter of explaining (in a formal letter) that their proposal will likely result in increased steel fabrication costs....
In my case, it also lead to increased corrosion due to possible contact with water. But, that was at least partially because that same construction manager refused to allow for any slab drainage.
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
I have used leveling nuts and no grout on poles and substation structures but never on a regular structural column.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Omitting Base Plate Grout
Omitting grout on minor columns may be okay where the bearing pressure is very small, but it isn't appropriate for loads of 250,000#. The bearing pressure will not be uniform under the baseplate.
BA
RE: Omitting Base Plate Grout
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
And require he polish/grind smooth/repour the concrete under each baseplate NOT bubble level both ways, exactly ruler-edge flat, and baby-butt smooth over the entire portion where every baseplate seats.
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
BA
RE: Omitting Base Plate Grout
If this sounds extreme, it is not. The people familiar with the circumstances always disappear, along with their memories of events, and then you have to deal with bean counters and lawyers who only look at what is written on the paper.
As I said before, if it was a viable way to build, we would all be doing it.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Omitting Base Plate Grout
Currenly, in hte meeting this morning, the owner stated that he did not want the grout after hearing from hte contractor. The Contractor who is a friend of hte Owner says he does this all the time.
I said I did not agree but offered as a compromise that they had to measure the elevation and levelness of hte first 8 foundations they pour. They agreed to this.
I do not beleive they can do this.
RE: Omitting Base Plate Grout
You will be involved if there are any problems, and the costs of grouting under the base plates would seem VERY minor compared to the cost of the whole building. Why is the GC taking such a hard stance on what seems to be such a small detail? I am also surprised at his cockiness to his concrete work and steel accuracy, the leveler nuts let you make adjustments to the elevations.
Light poles to not have 250k axial load. Also, the bolts and nuts are designed for this axial load.
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
Where can we as engineers draw the line and say we're not comfortable with that?
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
RE: Omitting Base Plate Grout
If not, you may be relying on the plastic action of concrete, crushing until sufficient bearing is achieved... I don't normally design on that basis...
Dik
RE: Omitting Base Plate Grout
BA