Agent666
Structural
- Jul 2, 2008
- 3,080
Hi all
In ACI318-19 chapter 17 (and earlier versions appendix D) :-
For checking combined actions on anchors if you are foregoing the shear and/or tension concrete breakout checks in lieu of adding specifically designed anchor reinforcement in accordance with ACI provisions. ACI isn't quite 100% clear in my mind on one thing...
Something I'm not quite 100% sure on is do you simply sub in your anchor reinforcement ratio for shear and/or tension in place of the concrete breakout and calculate combined actions check as normal if that reinforcement arrangement is still governing. The following suggests its a direct substitution and then presumably you carry on checking combined actions as normal?
Or once you have anchor reinforcement you are only required to satisfy the anchor design being greater than the demand isolated from the other checks (ratio of demand over capacity <=1), and just check combined action according to ACI for the other concrete and steel failure mechanisms only?
So options
1 - simply sub in anchor reinf ratio directly in place of the relevant concrete breakout.
2 - calc anchor reinforcement ratio and compare separately to demand, calculated other combined actions without the concrete breakout mechanism included.
For the life of me I cannot find any specific design examples as they all seem to only concentrate on the concrete breakout failures and maybe use supplementary reinforcement enhancements but not designing/providing specifically designed anchor reinforcement. Software such as Simpson anchor software only allows you to neglect the tension or shear breakout, but no design of the anchor reinforcement can be specified.
Anyone aware of the intended way to treat anchor reinforcement, or aware of any published design examples, or offer any advice on whether we're interpreting things correctly if following 1?
Hopefully that all made sense. If not let me know and I'll try explain things better!
In ACI318-19 chapter 17 (and earlier versions appendix D) :-
For checking combined actions on anchors if you are foregoing the shear and/or tension concrete breakout checks in lieu of adding specifically designed anchor reinforcement in accordance with ACI provisions. ACI isn't quite 100% clear in my mind on one thing...
Something I'm not quite 100% sure on is do you simply sub in your anchor reinforcement ratio for shear and/or tension in place of the concrete breakout and calculate combined actions check as normal if that reinforcement arrangement is still governing. The following suggests its a direct substitution and then presumably you carry on checking combined actions as normal?

Or once you have anchor reinforcement you are only required to satisfy the anchor design being greater than the demand isolated from the other checks (ratio of demand over capacity <=1), and just check combined action according to ACI for the other concrete and steel failure mechanisms only?
So options
1 - simply sub in anchor reinf ratio directly in place of the relevant concrete breakout.
2 - calc anchor reinforcement ratio and compare separately to demand, calculated other combined actions without the concrete breakout mechanism included.
For the life of me I cannot find any specific design examples as they all seem to only concentrate on the concrete breakout failures and maybe use supplementary reinforcement enhancements but not designing/providing specifically designed anchor reinforcement. Software such as Simpson anchor software only allows you to neglect the tension or shear breakout, but no design of the anchor reinforcement can be specified.
Anyone aware of the intended way to treat anchor reinforcement, or aware of any published design examples, or offer any advice on whether we're interpreting things correctly if following 1?
Hopefully that all made sense. If not let me know and I'll try explain things better!