PE Exam - Cantilever Retaining Wall Heel

[appot]

Studying for the PE Exam in these final 13 days, 15 hours, and 12 minutes...

My question is regarding the flexural design of the heel reinforcement in cantilever retaining walls. SERM includes the soil pressure under the heel to reduce the design moment. CERM, and all other references that I can find (including this thread), do not account for the soil pressure under the heel.

I do not expect to have to design the heel reinforcement on the PE exam, but any words of wisdom would be greatly appreciated.

 

[DETstru]

I think I understand your question...
I never use the pressure from below. Lets say your wall started to tilt, the heel would be supporting the weight of the soil above it with no support from below.

 

[Hokie93]

I believe it is typical practice to ignore upward soil pressure beneath the heel when determining heel thickness and reinforcing. This is the practice stipulated in "Design of Concrete Structures" (14th edition) by Nilson, Darwin, and Dolan.

Good luck on the exam!

 

[msquared48]

If the resultant is to the retained side, there can be upward net pressure to the heel. You just have to do the calcs and see what the load conditions show.

Mike McCann, PE, SE (WA)