Grout is used frequently in commercial construction, there are several types
available, I remember metallic and non-metallic as existing but forget why
you want one or the other . What grout is, is basically a very fine
concrete, which will flow very easily.....ie the mixed grout will pour/run
under your metal "feet" easily - it won't need to be forced to occupy the
cavity under the steel. It will take the weight once it sets up and serve to
transfer it to the slab below it - rather than having your leg up on a
"stilt." as it is now on the bolts. Frequently grout is used under heavy
machinery, the equipment is placed as you have done, onto threaded bolts -
levelled, and then: its grout time.
Check with a larger lumber yard or supplier of concrete related products such
as form release agents....do not look for this at a "home center". I suspect
you will not need much...the bags I remember carting over my shoulder were
about 25 lbs I think.
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com