Concrete anchorage for swept anchor rod

[SJBombero]

Is anyone familiar with a reference for the design of concrete anchorage for a swept anchor rod such as Simpson's SB1x30? The plan checker has thrown us a curve asking to justify the anchor reinforcement for a bent anchor rod.

 

[Deker]

Are you trying to justify the values for any bent anchor rod or a Simpson SB specifically? If an SB anchor, the design values are codified in their evaluation report and no additional justification is necessary.

 

[SJBombero]

I am trying to justify anchor reinforcement for a swept anchor rod of my own design. Evaluation reports for SB rods do not address anchor reinforcement and so would be inapplicable.

 

[Deker]

Not aware of any guidelines for swept anchors specifically, but since you intend to use anchor reinforcement I'm sure there is a way to break it down into a strut and tie problem. If you're able to post your proposed detail to scale it will help generate more meaningful discussion.

 

[SJBombero]

Here is the proposed detail for new moment frame rigid base next to an existing footing. Maximum anchor tension is 100 kip.

 

[Agent666]

Given what you've shown, to play devil's advocate why do you even need to crank the bolts? They appear like they would fit straight. What's limiting the capacity if they were straight?

https://engineervsheep.com

 

[SJBombero]

Despite the appearances, if the anchor were straight, the edge of the 4" bearing plate would be 4.5" from the edge of the foundation. Certainly sufficient clearance to the excavation. My reasoning was that given the need for anchorage reinforcement, a closed tie placed in the 3" available between the rod and the clear cover limit would not be developed enough to contribute.

 

[Agent666]

It would be no different than you've drawn in terms of the development. Your hairpin bars are close fitting around the bolts either way aren't they? Reality is your excavation can undermine the existing concrete a little to add additional cover if required to help with side face blowout if that governs.

https://engineervsheep.com

 

[Deker]

Agree with Agent that the anchors could be straight. If you'd like more clearance, I suggest offsetting the anchors rather than cranking them.