A few amatuerish questions
A few amatuerish questions
(OP)
Hello all,
During meetings I hear a lot of terms that I am unfamiliar with given that I am still green in the belly, I usually jot these unfamiliar terms down and try to discover what they mean referring to books.
One term that I did not understand and was not able to find anything on was "non-shrink" grout. What is the purpose of using "non-shrink" grout as opposed to normal grout (that I would presume shrinks?)
What about leveling nuts? What exactly are these leveling nuts, and when would you use them?
Sorry for the overly amateurish questions, but I'm learning. ;(
Thanks,
Clansman
During meetings I hear a lot of terms that I am unfamiliar with given that I am still green in the belly, I usually jot these unfamiliar terms down and try to discover what they mean referring to books.
One term that I did not understand and was not able to find anything on was "non-shrink" grout. What is the purpose of using "non-shrink" grout as opposed to normal grout (that I would presume shrinks?)
What about leveling nuts? What exactly are these leveling nuts, and when would you use them?
Sorry for the overly amateurish questions, but I'm learning. ;(
Thanks,
Clansman






RE: A few amatuerish questions
Non-shrink grout is typically used to fill voids that require the void to be 'full' after the grout has cured. For instance, under column base plates. The grout is used to fill the gap and provides continuity between the column base and the foundation allowing for the transmission of vertical loads through bearing, you can see how this wouldn't work if the grout shrank and left a void. The bolts are designed to take the shear and uplift (in reality shear would also be transferred through the grout by the bond between the grout and base plate).
Levelling nuts usually consist of a nut both above and below a column baseplate. They allow for the setting of the level of a column when setting out a building. The void being filled with the non shrink grout once the column base plate is set at the correct level.
RE: A few amatuerish questions
Then the usual (steel) nuts are put on the anchor bolts to hold the equipment securely to the concrete. The threads on the nylon nuts under the equipment can be counted on to strip if there is any movement. That way you are sure the grout/concrete is carrying the load rather than the anchor bolts.
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RE: A few amatuerish questions
I hope i gave you the correct explaination.
Never, but never question engineer's judgement
RE: A few amatuerish questions
Never, but never question engineer's judgement
RE: A few amatuerish questions
Yes, this is about steel baseplates.
What do you folks think about this statement that I heard, "anchor rods can not be relied upon to transfer any significant shear given that the holes are oversized for erection purposes." The holes are about 1/2" greater than the diameter of the rod.
I have followed code procedure to size up my anchor rods for both shear and tension, but now I am considering using shear lugs wherever I have shear greater than 50 kips. Does that sound reasonable?
RE: A few amatuerish questions
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RE: A few amatuerish questions
Non shrink grout is also sometimes referred to as shrinkage compensated grout.
RE: A few amatuerish questions
RE: A few amatuerish questions
We've started using embedded plates in the tops of the concrete supports on either side of the base plate. Then add vertical shear tab plates welded to the embedded plate and to the side edges of the base plate.
RE: A few amatuerish questions
Whoops, lunch is over. I need to wrap this up. I wouldn't want to advise you on an exact number for when to switch to shear tabs, but I would take the advice I cited and not count on all of the anchor bolts when they are in oversize holes. If you can lay your hands on that design guide I think you'll find it very helpful.
RE: A few amatuerish questions
I do what JAE does except I use post installed angles on both sides of the base plate anchored to the footing with screw anchors to prevent problems with the embeds missing or being misaligned.
RE: A few amatuerish questions