Pretensioning Anchor Bolts

[krus1972]

Hello,

My question is do anchor bolts have to be pretensioned before a moment is applied over the base plate?

I am working on the structural support of a new stair that is being placed in an existing building. The stair is very fancy and very very heavy.

To make a long story short I am saw-cutting the existing slab to make way for a new footing for a column to support the required loads.

The column will be installed first and then the footing will follow. The footing and the finish slab will be completed as one unit. The anchor bolts will be furnished and will be in the base plate before the footing/slab is placed. The Base Plate as well as the anchor bolt nuts will not be exposed after the footing/slab unit concrete is fully cured.

When everything is cured and ready to go moment will be applied over top placing some of the anchor bolts in tension. There is really no problem here accept that the anchor bolots will never have any pretension in them before the applied moment is applied over the base plate. Is this going to be a problem? If so, how so?


Thank you all,

Jeff

 

[Ron]

Jeff,
No, they don't have to be pretensioned, but the nuts should be at least "snug tight". I'm not a fan of pretensioning anchor bolts. They are generally not designed for that and I have seen no logical argument for the value of pretensioning that would be required.