Load reversal question

[danm494]

Hello to all, if I have a footing with bottom reinforcement only that undergoes moment reversal (say Mreversal= -100) and then I calculate the uncracked moment for rupture at the top fiber and find it to be much much larger like Mcr = 2000 would I still have to provide minimum top reinforcement at the top as per code? My Icr is taken using the full size of the footing namely 1/12bh^3 though the bottom may have been already cracked prior to the moment being reversed. thx for any help.

 

[KootK]

I don't see how you could crack the footing cross section in positive bending and then turn around and assume that same section to be uncracked for negative bending,

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[danm494]

yeah I was unsure about that and so my question. But the neg. moment is very very tiny. I'll just stick to code then and provide the min. rebar at the top