tying anchor bolted concrete to lower part of footings 1

[structengin]

Hi there,

Just wondering if anyone knew how to:

TIE ANCHOR BOLTED CONCRETE TO THE LOWER PART OF A FOOTING.


thanks.

 

[AggieYank]

Can you explain your question more clearly, or give a specific example?

My guess is that you are looking to reinfoce a typical footing (for example a 3' by 3' by 24" deep), where there is a mat of #5 @ 12" o.c. at the bottom, or something along those lines. You want to know how to tie the top of the footing (the column embed plate) to the rest of it. If this is the case, common practice is to pour the footing monolithically and to not use any extra reinforcing other than the bottom mat steel, and the embed plate. The headed studs themselves will either yield, pull out a cone of concrete, or shear off before something unusual such as the top of the footing breaking off from the bottom of the footing happens.

 

[rholder98]

I agree with AggieYank, except that my anchors are usually cast-in threaded rods, but it's the same net result.

Another scenario: if your footing bears significantly deeper than the column bearing elevation, you might use a square plinth (some call it a pier) to make up the difference. This, then, is essentially a concrete column bearing on a footing. I use bent dowels to anchor the plinth to the footing (is that what you're asking?), and square ties around the dowels. You also need to make sure the column anchors have enough embedment.

A better explanation of your question really would help. I've assumed all new construction. If you're talking about post-installed anchors, that's another story.