Ka for battered wall

[jbenway]

I am designing a gravity retaining wall for a state DOT using the AASHTO bridge design specifications. The wall will use large segmental blocks with a wall batter. I am calculating Ka using the batter of the back of the wall in the Coulomb equation. The reviewer says that I have to calculate Ka using a series of vertical faces. I believe that is contrary to generally accepted design pratice, but can find little justification for it in the AASHTO bridge manual. Can anyone provide any guidance on this?

 

[FixedEarth]

Google "NHI 132042 GEC 11" and get the 2 volume MSE wall set.

 

[jbenway]

I have a copy and am familiar with those two publications. Unfortunately they only discuss reinforced walls and not gravity walls.

 

[RFreund]

This is segmental gravity / conventional wall, no geogrid reinforcement correct?

I think the norm is to use the wall batter. I am not that familiar with AASHTO, but that is how NCMA does it. I'm not sure what he/you mean by using a series of vertical faces.
Could you show him fig 4-5 of NHI 132042 GEC 11 which uses the batter for finding Ka when performing external analysis. Which is the same thing you are doing with the gravity wall just without grid.

Just out of curiosity what system is it?



EIT

http://www.HowToEngineer.com