Temp. & Shrinkage Steel in Retaining Wall Stem at Footing 2

[Deadblow]

Hello,

I am designing a retaining wall and the concrete needs to be designed according to ACI 318-14. Please refer to the attachment for a general sense of what I am talking about. However, my specific design has different dimensions and loading than shown in the attachment. The vertical flexural steel at the back face of the wall stem that is anchored into the footing is adequate for the moment demand in the stem but the area of steel where the top of the footing meets the base of the stem does not meet the requirement of 0.0018x(gross concrete area). As shown in the attachment, I plan to have vertical steel in the front face of the wall resting on the top of the footing to meet the min. temperature and steel requirement for the stem. Do I need more area of steel crossing the plane where the stem meets the footing to meet the temperature and steel requirement at that specific location?

EIT

 

[Deadblow]

Thank you all for the responses and the discussion. I appreciate the input!

EIT

 

[Agent666]

That 1/3 greater than analysis moment thing you need to be careful with it. Especially where lateral loads exist where magnitude isn't fully known. For example wind, seismic or soil loads. NZ code pretty much has the same reduction but it is not allowed to be taken if the structure contributes to the lateral strength of the structure. Which is almost all structure in a seismically active country.

You need to appreciate the intent of the minimum reinforcement requirements and the heirarchy it sets up to ensure your reinforced strength is an arbitrary margin higher than the cracking strength.

I'd say a retaining wall is a situation where the lateral loads could quite easily be higher than you expected and as such if you did crack the wall and reinforcement was lower by taking the provisions to reduce the minimum reinforcement than you could get to a situation where you get a single crack, resulting in high bar strains and bar fracture or unforseen rotations.

 

[hoshang]

doe not the requirement below then govern and make 0.0018 a moot point?

Hi,
Despite the fact that this requirement is for beams, d is (12-2.5) not (10-2.5) and the denominator is 12*12 not 10*12.

 

[KootK]

Thanks for the corrections Hoshang. Unlike Trump, I relish fact checking.

 

[hoshang]

Thanks for the corrections Hoshang.

Hi
I wouldn't post the correction unless further calculations aren't done (Just based on my numbers here: 0.0025/0.0018 = 4/3 +/- 4%.)
Thank you KootK. I learned much from you and others in eng-tips.