Alternative to ACI Appendix D 1

[RFreund]

I wanted to know what alternatives where available to ACI Appendix D. I did find one helpful reference which I have attached as well. However I don't know how to design the reinforcement to prevent side face blow out. The article suggests that 1/4 of the tension force be used however I'm not sure how to find the amount or distribute the needed reinforcement (any guidance on this would be great).
Also any other anchorage solutions for the attached sketch showing an offset column pad footing.
I had thought of possibly using some anchor bolts that bent back into the footing however I'm not sure how to put a number to its capacity.

Thanks

EIT

 

[RFreund]

Attached is the referenced article

EIT

 

[Lion06]

Check out this article.

Additionally, reinforcement can't get you out of the woods for side face blowout, pryout, or pullout. It only helps with shear breakout and tension breakout. ACI 318-08 is much more explicit in this approach than '05 is.

You need to make sure that the bar (I would use rebar, not bent anchor rods) is fully developed above and below the failure plane that it crosses. There are also limitations on how far the rebar is allowed to be from the anchors.

 

[RFreund]

Thanks. That was a helpful article.

So, Ignoring shear for a minute I could provide enough "cover" to prevent side face blow-out and provide enough bearing (possibly steel plate or washer) to satisfy pullout and then develop some bars for tension breakout.
However in the Design of Anchor Reinforcement in Concrete Pedestals article I posted they reference:

Furche, J. and Eligehausen, R. (1991). “Lateral Blow-out Failure of Headed Studs Near a Free Edge,” Anchors in Concrete–Design and Behavior, SP-130, American Concrete Institute, Farmington Hills, Mich., pp. 235-252.
(not sure if this is a book or paper but I could not find it)

which states that blow-out would be prevented with 4.8db "cover" because blowout is independent of embedment when deeper than 12", (I did not find this in ACI, on C<0.4hef). Also it goes on to say that you can improve side face blow out but that it does not increase the capacity. Then they give the design force. This has me confused - can you improve the strength (increase capacity or not?)

Can I use 4.8db or do I need to stick with C>0.4hef?

Thanks again.

EIT

 

[Splitrings]

I just found this document today:

http://www.bechtel.com/assets/files/TechPapers/design-of-anchor-reinforcement.pdf

 

[Bobber1]

I design using "through bolts". They are specifically exempted from Appendix D. If they're for a foundation, I specify that a pocket be excavated in the earth below the bolts so the lower end of the bolt will have concrete corrosion protection. The drawing specifies where the bottom of the foundation is, making it clear that it is a through bolt relative to the foundation.

 

[ToadJones]

bobber-
You do this on large foundations with piers?
seems like a preposterous undertaking in such case

 

[ToadJones]

Freund-
What are you thinking of using the bearing plate for?
I don't think you'll need a bearing plate (although I have done this many times). I believe you can develop the full capacity of the anchor rod in tension with just a nut on the end of the anchor.
I believe excessively large plates can cause side face blowout and other problems.

I'm not sure if I am on base here, but I think in the past I have used the vertical pier bars to develop the anchors bolts/ make sure there is enough lap distance between the two. There are requirements for how far apart the vertical pier bars and anchors can be in order to consider the pier bars effective in developing the anchor rods.

I believe the two articles posted cover this.

I have had to embed large anchors over 8'-0 into piers in the past in order to accomplish this....right or wrong.

 

[ToadJones]

I have had that Bechtel Paper for a few years and I just now re-read it all the way through....IMO, that's a pretty good paper and is quite thorough. It covers a lot of things that ACI either ignores or only implies.

ACI APP D is really pretty sad...I'm not even sure why a topic this important is covered in an appendix.
I think they should dedicate a chapter to the topic and commit to being more thorough.