Question about tension development of hooked bars

[cliff234]

Question: ACI 318-14 has an equation for computing tension development lengths of hooked bars. Factors are listed in Table 25.4.3.2 (attached) that are applied to the equation. “Psi e” is an adjustment factor for spacing and cover. A factor 0.70 can be used when side cover (normal to the plane of the hook is > 2.5” AND for 90-degree hooks with cover on bar extension beyond hook >2”.

I am confused about two things.

First: What is the “cover on bar extension beyond hook”? (See the attached for two possible dimensions.) There is neither an explanation nor illustration in the Commentary. I have been confused about this for years (and have thus ignored the potential benefit of the 0.7 factor). Is this the concrete cover beyond the tip of the hook, the cover measured perpendicular to the hook, or something else? I think this is poorly worded.

Second: Can the 0.7 factor be used when EITHER of these requirements are met, or do both have to be met?

 

[RabitPete]

Looks like this has been already answered here:

https://www.eng-tips.com/viewthread.cfm?qid=438013

The answer is A

 

[Agent666]

Wasn't covered in the linked thread, but I believe both requirements need to be satisfied to take the 0.7 factor.

 

[r13]

To your 2nd question, the answer is "yes". See the image below.