Grouting a First-Tier Steel Column Base Plate

good questions,I'm not sure yet

You don't have to. You can support the base plate on steel shims while you erect the second level, then grout under the base plate later.

The steel structure may well be prefabbed, with perpendicular base plates. Slight variation in level and slope of a slab will necessitate field adjustment; e.g., leveling bolts and/or grout.

Thanks to all, the reason i asked is that the clients spec of steel erection requires me to grout the base plate after installing the first floor with all the beams, struts and bracing with plumbness check then grout the base plate before i could erect the second floor, i am trying to expediate my work without grouting yet until i finish my second floor, there is only 2 floors anyway. I am trying to argue my way out of it

There's a couple of reasons why you need to grout the underside of the column baseplate:

1. to provide a uniform spreading of the column load onto the concrete pier, so as not to overstress it and the steel baseplate.

2, You need to plumb both vertical axis of the column.

I've always thought (and been told) its simply to prevent water, dirt, and debris from accumulating beneath the base plate. I don't see how it could bear any load, even non-shrink grout shrinks a little. Even dry packing (which is what I'm used to) shrinks away when set.

Not arguing, just sharing my experience and thoughts.

Hello,

The grout that I usually specify on steel projects is a non-shrink/non-metallic grout with a shrinkage rate so small you cannot really measure it in the field + it sets up very quickly and gains roughly 90% of it's design compressive strength (over 15 ksi)within a few hours. You have to work fast mixing and placing it with great skill. Several chemical-mortar companies make the stuff...it's universally used throughout the iron working world! Hope this info helps!

Please see the post below yours - you apparently have not done field trials on this material.

Contrary to what people think, even the non-shrink grouts or expanding grouts do shrink substantially. İf you do trials using the grout manufacture's reps you will find that if they are very good they may manage 75% contact and probably less. İ know grout manufacturers and instructors will argue about this point but they are full of smoke and damn little real knowledge. A few years back İ sent a lot of effort on this for a steel mill - setting dummy base plates for equipment and after curing lifting them to see the quality of work. Even the most expensive grouts properly chained using water cooled to the correct temperature etc (all the possible rules) contact is fair at best. The grout certainly can not much carry load even if the mfg claims it does. Obviously the anchor bolts load carrying capacity is critical. There is no reason at all not to erect the second floor as well unless this is some kind of exotic structure. Anyone that says there is doesn't know what they are talking about.

Good answer, the only thing I would add is make sure you aren't the type of project manager that is perceived as a money grubber looking for the most insignificant extra or a way out of doing what you agreed to.

Since you have to grout at some point in time, what difference does it make? Why not go along with them on such a small issue? Choose a better hill to fight your battles on.