Minimum Reinforcement in footings

[amendale]

If I have a footing with top and bottom reinforcement, does the 0.002Ag minimum ratio apply to both top and bottom independently, or is it combined? In other words, which is correct:

0.002Ag < As + A's
OR
0.002Ag < As and 0.002Ag < A's

 

[jdgengineer]

You'll get different opinions on this forum as to the correct steel requirements for footings.

My interpretation is:

ACI 10.5.4 says that As,min needs to be the same as required by 7.12.2.1. As,min refers to the minimum flexural reinforcement. Therefore, you would need your flexural reinforcement to meet the requirements of 7.12.2.1. (Note most steel is Gr 60, therefore the requirement is 0.0018)

Other people will also say that unless you provide 1/3 more steel than required you need to additionally meet the requirements of 10.5.1. I don't typically do this for foundations, as it's my opinion that 10.5.4 does not require it.

 

[spats]

This subject has been beaten to death in earlier posts on this forum. Do a search.

 

[JoshPlumSE]

Beaten beyond death....

http://www.eng-tips.com/viewthread.cfm?qid=343576